TWI871700B - Ni-based abrasive material, abrasive liquid, method for manufacturing abrasive liquid, and glass polishing method - Google Patents

Abstract

A bismuth-based abrasive comprising mixed rare earth abrasive particles containing bismuth and bismuth, wherein the content of bismuth in terms of oxide (TREO) is 55.0 mass % or more. 10 g of the bismuth-based abrasive as a slurry component and 40 g of pure water are placed in a 100 mL polyethylene container together with 130 g of zirconia beads having a particle size of 1 mm as beads. The bismuth-based abrasive is pulverized using a ball mill at a container rotation speed of 210 rpm for 30 minutes, and the amount of bismuth dissolved in the obtained mixed solution is 40 mg/L or less.

Description

Ni-based abrasive material, abrasive liquid, method for manufacturing abrasive liquid, and glass polishing method

The present invention relates to a niobium-based abrasive, a polishing liquid, a method for producing the polishing liquid, and a glass polishing method. The niobium-based abrasive is a material used for polishing glass materials such as glass substrates used in liquid crystal panels, hard disks, filters for specific frequency cutoffs, and glass substrates for optical lenses.

Glass materials are used in a variety of applications, and depending on their application, surface polishing is sometimes required. In particular, glass materials such as glass substrates used in liquid crystal panels, hard disks, specific frequency cut-off filters, and glass substrates for optical lenses require high smoothness and high efficiency surface polishing.

In the surface grinding process of glass materials that require such excellent grinding performance, abrasive materials such as those described in Patent Document 1 or Patent Document 2 are widely used. [Prior Art Document] [Patent Document]

[Patent Document 1] International Publication No. 2005/042661 [Patent Document 2] International Publication No. 2002/031079

[The problem that the invention wants to solve]

As glass abrasives, generally used are caesium-based abrasives, and most of them contain titanium. Generally speaking, caesium-based abrasives are used in the form of slurry dispersed in water. The slurry is neutral to alkaline, and some users may experience skin irritation, such as skin roughening or dermatitis. Therefore, there is a demand for caesium-based abrasives with lower skin irritation and excellent operability.

This invention is completed to solve the above-mentioned problems. The problem is to provide a vanadium-based abrasive material, abrasive liquid, a method for manufacturing abrasive liquid, and a glass grinding method that can inhibit skin roughening and dermatitis. [Means for solving the problem]

The present invention is based on the discovery that, in a ballast containing mixed rare earth abrasive particles containing ballast and tantalum, the content of the ballast in terms of oxide conversion of all rare earth elements (TREO) is 55.0 mass % or more, and the amount of tantalum dissolved in a mixed solution containing the ballast and obtained by a specified method is 40 mg/L or less, thereby reducing skin roughening or dermatitis caused by adhesion to the skin.

That is, the present invention provides the following [1] to [16]. [1]. A bismuth-based abrasive, which is a bismuth-based abrasive containing mixed rare earth abrasive particles containing bismuth and bismuth, wherein, the content of the bismuth in terms of oxide (TREO) of all rare earth elements is 55.0% by mass or more, 10 g of the bismuth-based abrasive and 40 g of pure water, together with 130 g of zirconia beads having a particle size of 1 mm as beads, are placed in a 100 mL polyethylene container, and the bismuth-based abrasive is pulverized using a ball mill at a container rotation speed of 210 rpm for 30 minutes, so that the amount of bismuth dissolved in the obtained mixed solution is 40 mg/L or less. [2]. The niobium-based abrasive as described in [1], further comprising a titanium dissolution inhibitor. [3]. The niobium-based abrasive as described in [1], which is a two-component type, comprising: a first component containing the above-mentioned mixed rare earth abrasive particles, and a second component containing a titanium dissolution inhibitor. [4]. The niobium-based abrasive as described in [1], further comprising 0.1 to 10% by mass of fluorine atoms. [5]. The niobium-based abrasive as described in [1], further comprising a titanium dissolution inhibitor in the above-mentioned TREO. [6]. The vanadium-based abrasive as described in [2] or [3] above, wherein the aforementioned indium dissolution inhibitor is selected from alkali metal carbonates, alkali metal phosphates, alkali metal hydroxides, alkali metal sulfates, alkali metal nitrates, alkali metal organic acid salts, alkaline earth metal carbonates, alkaline earth [7]. The at least one of phosphates of alkali earth metals, hydroxides of alkali earth metals, sulfates of alkali earth metals, nitrates of alkali earth metals, organic acid salts of alkali earth metals, carbonates of ammonium, phosphates of ammonium, hydroxides of ammonium, sulfates of ammonium, nitrates of ammonium, and organic acid salts of ammonium. [6] The at least one of phosphates of alkali earth metals, hydroxides of alkali earth metals, sulfates of alkali earth metals, nitrates of ammonium, and organic acid salts of ammonium. [7]. The at least one of phosphates of alkali earth metals, hydroxides of alkali earth metals, sulfates of alkali earth metals, nitrates of ammonium, and organic acid salts of ammonium. [8]. The niobium-based abrasive described in [2] or [3] above, wherein the molecular weight of the aforementioned niobium dissolution inhibitor is 300 or less. [9]. The niobium-based abrasive described in [2] or [3] above, wherein the aforementioned niobium dissolution inhibitor is contained in an amount of 0.001 to 0.9 parts by mass per 100 parts by mass of the aforementioned mixed rare earth abrasive particles. [10]. A polishing liquid comprising: the niobium-based abrasive described in [1] above, and one or more selected from water and a water-soluble organic solvent. [11]. A method for producing a polishing liquid, which is the method for producing a polishing liquid described in [10], comprising the following step (I): Step (I): mixing the aforementioned bismuth-based abrasive with one or more selected from the aforementioned water and the aforementioned water-soluble organic solvent to form a slurry. [12]. A method for producing a polishing liquid as described in [11], wherein the aforementioned bismuth-based abrasive contains the aforementioned titanium dissolution inhibitor. [13]. A method for producing a polishing liquid, which is the method for producing a polishing liquid described in [10], comprising the following step (II): Step (II): mixing the aforementioned bismuth-based abrasive, the aforementioned titanium dissolution inhibitor, and one or more selected from the aforementioned water and the aforementioned water-soluble organic solvent to form a slurry. [14]. A method for producing a polishing liquid, which is the method for producing a polishing liquid described in [10], comprising the following steps (III) and (IV): Step (III): mixing the aforementioned niobium-based abrasive with one or more selected from the aforementioned water and the aforementioned water-soluble organic solvent to form a slurry; Step (IV): adding the aforementioned niobium dissolution inhibitor to the slurry obtained in the aforementioned step (III) and mixing it. [15]. A method for producing a polishing liquid as described in [14], wherein the aforementioned niobium-based abrasive does not contain the aforementioned dissolution inhibitor. [16]. A method for polishing glass, which is performed using the polishing liquid described in [10]. [Effect of the invention]

The present invention can provide a vanadium-based abrasive material, abrasive liquid, a method for manufacturing the abrasive liquid, and a glass polishing method that can inhibit skin roughening and dermatitis.

[Best Mode for Carrying Out the Invention]

The following is a detailed description of the embodiments of the bismuth-based abrasive, polishing liquid, method for producing the polishing liquid, and glass polishing method of the present invention. In addition, in this specification, the so-called "50% particle size in the cumulative particle size distribution based on volume" and " _D50 " refer to the particle size that becomes 50% in the cumulative particle size distribution based on volume obtained from the particle size distribution measured by the laser diffraction and scattering method. Specifically, it is the value measured by the Microtrac particle size analyzer described in the following examples.

[Cabolium-based abrasive] The cabolium-based abrasive of the present embodiment is a cabolium-based abrasive containing mixed rare earth abrasive particles containing vanadium and vanadium, wherein the content of the cabolium-based oxide (CeO ₂ ) (hereinafter referred to as "CeO ₂ amount/TREO") in the total rare earth element content (TREO; abbreviation for Total Rare Earth Oxides) is 55.0 mass % or more. Then, 10 g of the cabolium-based abrasive and 40 g of pure water were placed in a 100 mL polyethylene container together with 130 g of zirconia beads having a particle size of 1 mm as beads, and the cabolium-based abrasive was pulverized using a ball mill at a container rotation speed of 210 rpm for 30 minutes, and the amount of vanadium dissolved in the obtained mixed solution was 40 mg/L or less.

The TREO in the diaphragm of this embodiment is set to be from mixed rare earth abrasive particles. The TREO in the mixed rare earth abrasive particles is preferably 85.0 mass % or more, more preferably 90.0 mass % or more, and more preferably 92.0 mass % or more from the viewpoint of improving the polishing rate. From the viewpoint of including elements other than the elements constituting TREO and further improving the polishing rate and suppressing the generation of surface defects on the polished surface, it is preferably 99.0 mass % or less, more preferably 98.0 mass % or less, and more preferably 95.0 mass % or less from the viewpoint of containing elements other than the elements constituting TREO and further improving the polishing rate and suppressing the generation of surface defects on the polished surface.

The content of the aforementioned cerium in TREO as converted to oxide (CeO ₂ ) (CeO ₂ amount/TREO) is 55.0 mass % or more, preferably 60.0 mass % or more, more preferably 62.0 mass % or more, and more preferably 64.0 mass % or more from the viewpoint of improving the polishing rate. Furthermore, from the viewpoint of ensuring the content of rare earth elements other than Ce and suppressing the generation of surface defects on the polished surface, CeO ₂ amount/TREO is preferably 90.0 mass % or less, more preferably 80.0 mass % or less, more preferably 75.0 mass % or less, and more preferably 70.0 mass % or less.

The content of the aforementioned vanadium in TREO calculated as oxide (La ₂ O ₃ ) (hereinafter referred to as "La ₂ O ₃ amount/TREO") is preferably 0.01 mass % or more, more preferably 1.0 mass % or more, more preferably 10.0 mass % or more, more preferably 20.0 mass % or more, and more preferably 30.0 mass % or more from the viewpoint of suppressing the generation of scratches on the polished surface. Since the Ce amount in TREO is 55.0 mass % or more, the La ₂ O ₃ amount/TREO is 45.0 mass % or less, and from the viewpoint of improving the polishing rate and further reducing the skin roughening and dermatitis, it is preferably 40.0 mass % or less, more preferably 37.0 mass % or less, and more preferably 35.0 mass % or less.

TREO can be measured by oxalate precipitation, calcination and weight method. Specifically, it can be measured by the method described in the embodiment described below. In addition, the content of each rare earth element such as Ce or La can be measured by machine analysis such as high-frequency inductively coupled plasma (ICP) analysis or fluorescent X-ray analysis. In this embodiment, the measured value obtained by ICP atomic emission spectrometry (ICP-AES) is converted into the value of each rare earth element as an oxide and determined as the oxide conversion amount.

The reason why the vanadium-based abrasive of this embodiment can suppress skin roughening or dermatitis is not clear, but it is considered to be as follows. The titanium contained in the vanadium-based abrasive will be eluted in the form of titanium ions when the vanadium-based abrasive is manufactured or slurried, and dissolved in water or a water-soluble organic solvent. When the amount of titanium dissolved in the liquid is large, it will combine with chloride ions from the raw materials of the vanadium-based abrasive to generate highly toxic titanium chloride, which will adhere to the human skin and cause skin roughening or dermatitis. On the other hand, by setting the amount of dissolved titanium to a low concentration of 40 mg/L or less, the generation of titanium chloride and the like is suppressed, and as a result, it is believed that the occurrence of skin roughening or dermatitis is suppressed.

The amount of dissolved titanium in the mixed solution obtained by the above-specified method is 40 mg/L or less. From the perspective of suppressing skin roughening and dermatitis, it is preferably 35 mg/L or less, more preferably 30 mg/L or less, and more preferably 25 mg/L or less. From the perspective of cost, it is preferably 0.1 mg/L or more, more preferably 0.5 mg/L or more, and more preferably 1.0 mg/L or more. In addition, if the vanadium-based abrasive of this embodiment is used in a slurry state using an actual machine, the ratio of the vanadium-based abrasive to water and water-soluble organic solvent as a dispersion medium in the slurry will be different from that of the above-specified method. However, as long as the concentration of dissolved titanium is below the concentration measured by the measurement method, the effect of this embodiment can be exhibited. In this specification, the so-called "amount of titanium dissolved" refers to the value calculated by ICP analysis, specifically, the value calculated by the method described in the following embodiment.

During the manufacture of the calcined abrasive or during the slurrying process, chloride ions from the raw materials of the calcined abrasive will also dissolve in water or a water-soluble organic solvent together with the titanium ions. The amount of chlorine dissolved in the mixed solution obtained by the above-specified method is preferably 40 mg/L or less, more preferably 35 mg/L or less, and more preferably 25 mg/L or less from the viewpoint of further suppressing the occurrence of skin roughening and dermatitis, and preferably 0.1 mg/L or more, more preferably 0.5 mg/L or more, and more preferably 1.0 mg/L or more from the viewpoint of cost. In this specification, the so-called "chlorine dissolved amount" refers to the value calculated by ICP analysis, specifically, the value calculated by the method described in the following embodiment.

The particle size (D ₅₀ ) of the caesium-based abrasive of the present embodiment is preferably 0.10 μm or more, more preferably 0.3 μm or more, more preferably 0.5 μm or more, and more preferably 0.7 μm or more from the viewpoint of producing the caesium-based abrasive with good productivity. From the viewpoint of reducing grinding scratches and smoothing the grinding surface well to obtain excellent grinding performance, D ₅₀ is preferably 10.0 μm or less, more preferably 5.0 μm or less, and more preferably 3.0 μm or less.

The specific surface area of the vanadium-based abrasive of the present embodiment is preferably 1.0 ^{m 2} /g or more, more preferably 2.0 m ² /g or more, and more preferably 3.0 m ² /g or more from the viewpoint of suppressing the generation of scratches (wounds) on the polished surface, and is preferably 10.0 m 2 /g or less, more preferably 8.0 m ² /g or less, more preferably 7.0 ^{m 2 /} g or less, and more preferably 6.0 ^{m 2} /g or less from the viewpoint of increasing the polishing rate. In addition, in this specification, the specific surface area is a value measured by the BET method (one-point method).

The niobium-based abrasive of this embodiment may also contain fluorine atoms from the viewpoint of improving the polishing speed. If the niobium-based abrasive contains fluorine atoms, the fluorine atom content in the niobium-based abrasive is preferably 0.1 mass % or more, more preferably 1.0 mass % or more, and more preferably 3.0 mass % or more from the viewpoint of improving the polishing speed, and preferably 10.0 mass % or less, more preferably 9.0 mass % or less, more preferably 8.0 mass % or less, and more preferably 7.0 mass % or less from the viewpoint of suppressing the generation of scratches on the polished surface. The niobium-based abrasive is alkali-melted and converted into an aqueous solution, and the fluorine atom content in the niobium-based abrasive can be measured by an ion electrode method.

The content of TREO in the vanadium-based abrasive of the present embodiment is preferably 85.0 mass % or more, more preferably 90.0 mass % or more, and more preferably 92.0 mass % or more from the viewpoint of improving the polishing rate. From the viewpoint of including elements other than the elements constituting TREO and further improving the polishing rate and suppressing the generation of surface defects (fine asperities on the surface) on the polished surface, it is preferably 99.0 mass % or less, more preferably 97.0 mass % or less, and more preferably 96.0 mass % or less.

(Mixed rare earth abrasive particles) The mixed rare earth abrasive particles in this embodiment, the so-called "mixed" means containing multiple rare earth elements. The mixed rare earth abrasive particles may also contain rare earth elements other than Ce and La (Luminium). Examples of the rare earth elements include Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, etc.

The particle size (D ₅₀ ) of the mixed rare earth abrasive particles of the present embodiment is preferably 0.10 μm or more, more preferably 0.3 μm or more, more preferably 0.5 μm or more, and more preferably 0.7 μm or more, from the viewpoint of producing a caesium-based abrasive with good productivity. From the viewpoint of reducing grinding scratches and smoothing the grinding surface well to obtain excellent grinding performance, it is preferably 10.0 μm or less, more preferably 5.0 μm or less, and more preferably 3.0 μm or less.

The specific surface area of the mixed rare earth abrasive particles of this embodiment is preferably 1.0 m ² /g or more, more preferably 2.0 m ² /g or more, and more preferably 3.0 m ² /g or more from the viewpoint of suppressing the generation of scratches (wounds) on the polished surface, and is preferably 10.0 m 2 /g or less, more preferably 8.0 m ² /g or less, more preferably 7.0 ^{m 2 /} g or less, and more preferably 6.0 m ² /g or less from the viewpoint of increasing the polishing rate. In addition, in this specification, the specific surface area is a value measured by the BET method (one-point method).

The mixed rare earth abrasive particles of this embodiment may also contain fluorine atoms from the perspective of improving the polishing speed. If the mixed rare earth abrasive particles contain fluorine atoms, the fluorine atom content in the mixed rare earth abrasive particles is preferably 0.1 mass % or more, more preferably 1.0 mass % or more, and more preferably 3.0 mass % or more from the perspective of improving the polishing speed, and preferably 10.0 mass % or less, more preferably 9.0 mass % or less, more preferably 8.0 mass % or less, and more preferably 7.0 mass % or less from the perspective of suppressing the generation of scratches on the polished surface.

(Luminium dissolution inhibitor) The vanadium-based abrasive of this embodiment may contain a luminium dissolution inhibitor for inhibiting the dissolution of luminium in addition to the above-mentioned mixed rare earth abrasive particles. As the luminium dissolution inhibitor, it is preferred to use a luminium dissolution inhibitor that has the effect of converting luminium ions dissolved in water or a water-soluble organic solvent into insoluble salts and precipitating them, or a luminium dissolution inhibitor that has the effect of immobilizing luminium ions by chelation. As such a titanium dissolution inhibitor, it is preferably selected from alkali metal carbonates, alkali metal phosphates, alkali metal hydroxides, alkali metal sulfates, alkali metal nitrates, alkali metal organic acid salts, alkali earth metal carbonates, alkali earth metal phosphates, alkali earth metal hydroxides, alkali earth metal sulfates, alkali earth metal nitrates, alkali earth metal organic acid salts. One or more of organic acid salts of earth metals, ammonium carbonates, ammonium phosphates, ammonium hydroxides, ammonium sulfates, ammonium nitrates, and organic acid salts of ammonium; from the viewpoint of the safety of the generated salt, it is more preferable to select one or more of carbonates of alkaline earth metals, phosphates of alkaline earth metals, organic acid salts of alkaline earth metals, and carbonates of alkaline metals.

As alkaline metals, sodium and potassium are preferred from the viewpoint of the safety of the generated salts, and sodium is more preferred. As alkaline earth metals, calcium and magnesium are preferred from the same viewpoint. As the inhibitor of indium dissolution, specifically, calcium dihydrogen phosphate, calcium hydrogen phosphate, calcium hydroxide, calcium carbonate, calcium gluconate, calcium citrate sodium bicarbonate, ammonium hydrogen carbonate, magnesium hydrogen phosphate, and calcium hydrogen phosphate are preferred. Among them, calcium hydrogen phosphate (dibasic calcium phosphate) is more preferred from the viewpoint of further suppressing the occurrence of skin roughening and dermatitis, the safety of the generated salt, and suppressing the occurrence of scratches on the polished surface. The onium dissolution inhibitor may be used alone or in combination of two or more.

In addition, the molecular weight of the indium dissolution inhibitor is preferably 50 or more, more preferably 75 or more, more preferably 100 or more, and preferably 300 or less, more preferably 200 or less, and more preferably 150 or less from the viewpoint of further suppressing the occurrence of skin roughening and dermatitis. When the molecular weight is 300 or less, the reactivity with indium ions is high, and the effect of suppressing indium dissolution is high, which is preferred.

If the niobium-based abrasive of the present embodiment contains a titanium dissolution inhibitor, the niobium-based abrasive may be a one-dose type containing the titanium dissolution inhibitor in advance, or may be a two-dose type containing: a first agent containing the aforementioned mixed rare earth abrasive particles, and a second agent containing the titanium dissolution inhibitor.

If the aforementioned phthalocyanine-based abrasive is a two-part type, comprising: a first part containing the aforementioned mixed rare earth abrasive particles, and a second part containing an indium dissolution inhibitor, etc., the content of the mixed rare earth abrasive particles in the aforementioned first part is preferably 85.0 mass % or more, more preferably 90.0 mass % or more, and more preferably 92.0 mass % or more from the viewpoint of improving the polishing speed, and is preferably 99.9 mass % or less, more preferably 99.5 mass % or less, and more preferably 99.2 mass % or less from the viewpoint of inhibiting the occurrence of skin roughening and dermatitis.

The content of the indium dissolution inhibitor in the indium-based abrasive is preferably 0.95 parts by mass or less, more preferably 0.85 parts by mass or less, and more preferably 0.75 parts by mass or less, relative to 100 parts by mass of the mixed rare earth abrasive particles, in terms of cost. In addition, in terms of inhibiting the occurrence of skin roughening and dermatitis, it is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and more preferably 0.1 parts by mass or more. In addition, the content of the indium dissolution inhibitor in the indium-based abrasive is preferably 0.95 mass% or less, preferably 0.90 mass% or less, more preferably 0.80 mass% or less, and more preferably 0.70 mass% or less from the perspective of cost in both the one-dose type and the two-dose type. In addition, from the perspective of inhibiting skin roughening and dermatitis, it is preferably 0.001 mass% or more, more preferably 0.01 mass% or more, more preferably 0.05 mass% or more, and more preferably 0.1 mass% or more.

(Additives) The calcined abrasive of this embodiment may also be added with additives such as diols such as ethylene glycol and polyethylene glycol, sodium salt of polyacrylic acid, polymer dispersants such as polycarboxylic acid polymers and polysulfonic acid polymers, cellulose ethers such as methyl cellulose and carboxymethyl cellulose, water-soluble polymers such as polyvinyl alcohol, and phosphoric acid compounds for the purpose of improving dispersibility, preventing sedimentation, preventing solidification, improving stability, and improving workability. These may be used alone or in combination of two or more. When additives are added, polymer dispersants, phosphoric acid compounds, and cellulose ethers are preferred from the viewpoint of better improving dispersibility, preventing sedimentation, preventing solidification, improving stability, and improving workability. As polymer dispersants, for example, poly(meth)acrylic acid, polyhydroxy(meth)acrylic acid, (meth)acrylic acid and maleic acid copolymers, olefin and maleic acid copolymers, maleic acid and allyl alcohol ethylene oxide or propylene oxide alkylene oxide adduct copolymers, allyl sulfonic acid and maleic acid copolymers, or sodium salts, potassium salts of these alkali metal salts. Among these, polyacrylic acid, acrylic acid and maleic acid copolymers, or alkali metal salts of these are preferred; acrylic acid and maleic acid copolymers or alkali metal salts are more preferred, and sodium salts of acrylic acid and maleic acid copolymers are more preferred. Phosphoric acid compounds include inorganic phosphoric acids such as tripolyphosphoric acid, pyrophosphoric acid, tetrametaphosphoric acid, hexametaphosphoric acid, orthophosphoric acid, and phosphorous acid; organic phosphonic acids such as aminotrimethylenephosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetramethylenephosphonic acid, and diethylenetriaminepentamethylenephosphonic acid; or alkali metal salts thereof such as sodium salts and potassium salts. Among them, tripolyphosphoric acid, pyrophosphoric acid, hexametaphosphoric acid, or alkali metal salts thereof are preferred, and sodium tripolyphosphate is more preferred.

If the diatomaceous earth abrasive contains additives, from the perspective of improving dispersibility, preventing sedimentation, preventing solidification, improving stability and improving workability, the content of the additive is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and more preferably 0.5 parts by mass or more relative to 100 parts by mass of the mixed rare earth abrasive particles. From the perspective of cost, it is preferably 10.0 parts by mass or less, more preferably 5.0 parts by mass or less, and more preferably 3.0 parts by mass or less. Furthermore, if the vanadium-based abrasive contains an additive, the content of the additive in the vanadium-based abrasive is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, more preferably 0.3 mass% or more, and more preferably 0.5 mass% or more from the perspective of improving dispersibility, preventing sedimentation, preventing solidification, improving stability, and improving workability. From the perspective of cost, it is preferably 10.0 mass% or less, more preferably 5.0 mass% or less, and more preferably 3.0 mass% or less.

[Manufacturing method of niobium-based abrasives] The manufacturing method of niobium-based abrasives is not particularly limited. Specifically, it is preferable to manufacture niobium-based abrasives by the following steps: preparing a mixed light rare earth compound (1), preparing a mixed rare earth oxide raw material from the mixed light rare earth compound (2), and wet-grinding the mixed rare earth oxide raw material and then calcining, crushing and classifying to obtain mixed rare earth abrasive particles (3). In addition, from the perspective of further inhibiting the occurrence of skin roughening and dermatitis, it is more preferable to manufacture niobium-based abrasives by adding a mixed titanium dissolution inhibitor or preparing a second agent containing a titanium dissolution inhibitor after the aforementioned step (3). The "mixing" mentioned here is also synonymous with the "mixing" of the mixed rare earth abrasive particles mentioned above. The following describes each step in order.

(Step (1)) Step (1) is to prepare a mixed light rare earth compound. The preparation method of the mixed light rare earth compound is not particularly limited. The mixed light rare earth compound is obtained, for example, by separating and reducing impurities other than rare earth elements and medium and heavy rare earths from an ore containing rare earth elements by chemical treatment. As a mixed light rare earth compound, it is preferred that the impurities such as non-rare earth components such as alkali metals, alkaline earth metals and radioactive substances, and the content of medium and heavy rare earths are reduced. In this specification, the so-called medium and heavy rare earths refer to rare earth elements with an atomic number greater than Pm, and rare earth elements other than medium and heavy rare earths are called light rare earths. As the ore containing rare earth elements, for example, rare earth concentrate obtained from raw material ore such as natural monazite or fluorocarbon ore containing a large amount of Ce can be suitably used.

When preparing mixed light rare earth compounds, sulfuric acid roasting is a general method as a chemical treatment method for reducing the content of impurities. Sulfuric acid roasting is a method in which the crushed raw ore is roasted with sulfuric acid to generate sulfate (rare earth sulfate), the sulfate is dissolved in water to form a rare earth sulfate solution, and the insoluble impurities are removed by filtering. The content of impurities in the mixed light rare earth compound is preferably reduced to 1.0 mass % or less. In addition, as a chemical treatment method for reducing the content of medium and heavy rare earths, for example, carbonate can be added to the rare earth sulfate solution after the sulfuric acid roasting to make it a crude rare earth carbonate, and then hydrochloric acid is added to it to make it a mixed rare earth chloride aqueous solution, and solvent extraction is performed using an organic solvent. During solvent extraction, the contents of arsenic, chalcanthite and other light rare earths can be adjusted by known methods such as adjusting the degree of extraction or using additives as needed. The content of medium and heavy rare earths in the mixed light rare earth compound is preferably reduced to less than 1.0 mass %.

(Step (2)) Step (2) is to produce a mixed rare earth oxide raw material from a mixed light rare earth compound. The method for producing a mixed rare earth oxide raw material from a mixed light rare earth compound is not particularly limited. The mixed rare earth oxide raw material is obtained by, for example, using a mixed light rare earth compound and sodium carbonate or ammonium bicarbonate to produce a mixed rare earth carbonate carbonate, and then calcining the mixed rare earth carbonate. The calcination temperature when calcining the mixed rare earth carbonate to obtain the mixed rare earth oxide raw material is appropriately adjusted according to the composition of the mixed rare earth carbonate, preferably 500~1200℃, more preferably 600~1100℃, and more preferably 700~1000℃. The calcination time is preferably 0.5 to 48 hours, more preferably 1 to 40 hours, and even more preferably 1.5 to 30 hours. The calcination environment is preferably in an atmospheric environment. The mixed rare earth oxide raw material can also be crushed by mechanical methods after calcination to adjust the particles to the desired particle size.

In addition, mixed rare earth oxide raw materials are also commercially available, and commercial products can also be used. Mixed rare earth oxide raw materials can be obtained by, for example, calcining mixed light rare earth compounds such as mixed rare earth carbonates, mixed rare earth monocarbonates, mixed rare earth oxalates, and mixed rare earth hydroxides. Therefore, mixed rare earth carbonates, mixed rare earth monocarbonates, mixed rare earth oxalates, and the like, which are the raw materials for their production, may also remain in commercially available mixed rare earth oxide raw materials.

(Step (3)) Step (3) is to wet-grind the mixed rare earth oxide raw material and then calcine, crush and grade it to obtain mixed rare earth abrasive particles. From the perspective of obtaining uniform mixed rare earth abrasive particles, wet pulverization is preferably performed using a media mill such as a wet ball mill. As a dispersion medium, water, a water-soluble organic solvent, etc. are suitable. After wet pulverization, drying, calcine, crushing and classification are performed to obtain mixed rare earth abrasive particles. Drying, calcine, crushing and classification can be performed in the same manner as the method used in the production of mixed rare earth abrasive particles in the past.

Furthermore, from the viewpoint that the raw materials to be fired can be fully reacted by firing, the firing temperature is preferably 600-1200°C, more preferably 650-1150°C, and more preferably 700-1100°C. The firing time at the target setting temperature is preferably 0.1-10 hours, more preferably 0.5-6 hours, and more preferably 0.5-4 hours. The firing environment is preferably in an atmospheric environment.

From the perspective of improving the polishing speed, there is also a case where fluorine atoms are contained in the mixed rare earth abrasive particles. In this case, the method of containing fluorine atoms is not particularly limited, and the following method is preferred: a mixed rare earth fluoride raw material is mixed with a mixed rare earth oxide raw material, and after wet pulverization, calcination, crushing and classification are performed to obtain mixed rare earth abrasive particles.

The method for obtaining the mixed fluoride rare earth raw material is not particularly limited. For example, it can be obtained by adding fluoride such as hydrofluoric acid, ammonium fluoride or acidic ammonium fluoride as a fluorine source to the mixed light rare earth compound and performing heat treatment. From the perspective of obtaining a uniform niobium-based abrasive with excellent grinding properties, the heat treatment is preferably below 400°C. In addition, the heat treatment environment is preferably in the atmosphere. The heat treatment time is preferably 0.1 to 10 hours, more preferably 0.5 to 5 hours, and more preferably 1.0 to 4 hours. The sintering environment is preferably in the atmosphere. The method of mixing a mixed rare earth fluoride raw material into a mixed rare earth oxide raw material to obtain mixed rare earth abrasive particles is safer and more cost-effective than the method of directly adding fluorides such as ammonium fluoride or hydrofluoric acid to a mixed rare earth oxide raw material to obtain mixed rare earth abrasive particles. Mixed rare earth abrasive particles containing fluorine can be easily obtained.

The content of TREO in the mixed rare earth fluoride raw material is preferably 75% by mass or more, more preferably 80% by mass or more, and more preferably 82% by mass or more. In addition, the mixed rare earth fluoride raw material preferably contains thorium as the main component among all the rare earth elements contained. The content of thorium in TREO in terms of oxide conversion (CeO ₂ amount/TREO) is preferably 55.0% by mass or more, and from the viewpoint of improving the polishing rate, it is preferably 60.0% by mass or more, more preferably 62.0% by mass or more, and more preferably 64.0% by mass or more. Furthermore, from the viewpoint of ensuring the content of rare earth elements other than Ce and suppressing the generation of surface defects on the polished surface, the CeO2 _amount /TREO is preferably 90.0 mass % or less, more preferably 80.0 mass % or less, more preferably 75.0 mass % or less, and even more preferably 70.0 mass % or less.

Furthermore, the fluorine atom content in the aforementioned mixed rare earth fluoride raw material is preferably 10-30 mass%, more preferably 15-30 mass%, and more preferably 20-30 mass%. The amount of the mixed rare earth fluoride raw material added to the mixed rare earth oxide raw material can be appropriately determined according to the fluorine atom content required for the manufactured niobium-based abrasive. From the perspective of obtaining excellent polishing properties, the amount of the mixed rare earth fluoride raw material is preferably added in an amount of 1-40 mass%, more preferably 3-35 mass%, and more preferably 5-30 mass%, relative to 100 mass% of the total of the mixed rare earth oxide raw material and the mixed rare earth fluoride raw material.

(Step (4)) Step (4) is to add a mixed titanium dissolution inhibitor to the mixed rare earth abrasive particles obtained in step (3) after step (3), or to prepare a second agent containing a titanium dissolution inhibitor. In this embodiment, if the niobium-based abrasive is a one-agent type, the mixed rare earth abrasive particles can be directly used as a niobium-based abrasive without going through step (4); or, the titanium dissolution inhibitor can be added and mixed into the mixed rare earth abrasive particles obtained in step (3) to be used as a niobium-based abrasive. In addition, according to the needs, the titanium dissolution inhibitor and the additive can be added and mixed together. The mixing method is not particularly limited. For example, mixing can be performed using a batch mixer or a medium mill such as a ball mill or a bead mill. In this embodiment, if the niobium-based abrasive is a two-component type, the second agent containing the titanium dissolution inhibitor is prepared by step (4). In this embodiment, if it is a two-component type, the two-component type contains: a first agent containing the niobium-based abrasive particles of the mixed rare earth abrasive particles and a second agent containing the titanium dissolution inhibitor. Alternatively, the first agent containing the mixed rare earth abrasive particles and the second agent containing the titanium dissolution inhibitor may be prepared separately, and the first agent and the second agent may be mixed when the polishing liquid is prepared. The aforementioned second agent may contain water, water-soluble organic solvents, additives, etc. in addition to the onium dissolution inhibitor, but it may not contain them.

[Polishing liquid] The polishing liquid of this embodiment contains: a calcined abrasive as described above, and one or more selected from water and a water-soluble organic solvent. From the viewpoint of further suppressing the occurrence of skin roughening and dermatitis, the aforementioned polishing liquid preferably contains a titanium dissolution inhibitor. In addition, the aforementioned polishing liquid may also contain: a calcined abrasive, one or more selected from water and a water-soluble organic solvent, and components other than the titanium dissolution inhibitor. The polishing liquid of this embodiment is a polishing liquid that can suppress skin roughening or dermatitis, etc., which occurs when it adheres to the skin of the human body.

In terms of achieving good polishing performance and cost, the content of the abrasive material in the polishing liquid is preferably in the range of 0.1-40.0 mass %, preferably 1.0-35.0 mass %, more preferably 3.0-30.0 mass %, and more preferably 5.0-20.0 mass %. In addition, the polishing liquid may be prepared with additives such as pH adjusters, defoamers, and anti-rust agents as needed within the range that does not hinder the polishing performance, taking into account the specifications of the polishing object or the polishing device.

The above-mentioned polishing liquid is particularly suitable for the finishing and polishing of various glass materials and glass products such as glass substrates for optical disks or magnetic disks, glass substrates for liquid crystal displays, glass substrates for color filters or masks, and glass substrates for optical lenses.

[Method for producing polishing liquid] The method for producing polishing liquid of the present invention is a method for producing polishing liquid containing the above-mentioned bismuth-based abrasive and one or more selected from water and water-soluble organic solvents. In one embodiment of the present invention, the method for producing polishing liquid comprises the following step (I), step (I): mixing the above-mentioned bismuth-based abrasive and one or more selected from the above-mentioned water and the above-mentioned water-soluble organic solvent and slurrying them. In this case, the above-mentioned bismuth-based abrasive may also contain the above-mentioned bismuth dissolution inhibitor, but it may not contain it.

Furthermore, if the niobium-based abrasive is a two-agent type, wherein the two-agent type contains: a first agent containing mixed rare earth abrasive particles, and a second agent containing a titanium dissolution inhibitor, the first agent and the second agent are used as the aforementioned niobium-based abrasive to perform step (I).

In step (I), the method for slurrying is not particularly limited. For example, slurrying can be performed by mixing with a stirrer, or by using a wet ball mill, a grinding machine, a bead mill or the like.

In other aspects of the present invention, the method for preparing the polishing liquid comprises the following step (II): Step (II): mixing the aforementioned bismuth-based abrasive, the aforementioned titanium dissolution inhibitor, and one or more selected from the aforementioned water and the aforementioned water-soluble organic solvent to form a slurry. In this case, the aforementioned bismuth-based abrasive may also contain the aforementioned titanium dissolution inhibitor, but it may not contain it. The method for forming a slurry in step (II) is the same as the method for forming a slurry in step (I).

In another embodiment of the present invention, the method for preparing the polishing liquid comprises the following steps (III) and (IV), wherein the step (III) comprises mixing the aforementioned niobium-based abrasive with one or more selected from the aforementioned water and the aforementioned water-soluble organic solvent to form a slurry; and the step (IV) comprises adding and mixing the aforementioned titanium dissolution inhibitor into the slurry obtained in the aforementioned step (III). The aforementioned niobium-based abrasive may contain the aforementioned titanium dissolution inhibitor, but may not contain it. The method for forming a slurry in step (III) is the same as the method for forming a slurry in step (I).

[Glass polishing method] The glass polishing method of the present invention is a method for polishing using the polishing liquid as described above. The aforementioned glass polishing method is not particularly limited except for using the aforementioned polishing liquid, and a method using a known polishing device or the like can be applied. The aforementioned polishing liquid can be used by a known method when performing finishing polishing such as mirror polishing of a glass material using a single-sided polisher or a double-sided polisher. [Example]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the following examples. In addition, the preparation of the mixed rare earth oxide raw material, the preparation of the mixed rare earth fluoride raw material, the TREO of the examples and comparative examples, the content of each rare earth element in TREO in terms of oxide conversion (CeO ₂ amount/TREO, La ₂ O ₃ amount/TREO, Nd ₂ O ₃ amount/TREO, Pr ₆ O ₁₁ amount/TREO), and the fluorine atom content are obtained as follows. [TREO] Aqueous ammonia is added to a solution in which a test sample is dissolved in an acid. The resulting precipitate is filtered and washed to remove the alkaline metal, and then acid-dissolved again. Oxalic acid is added to the solution, and the resulting precipitate is calcined at 800°C for 2 hours in the atmosphere, and TREO is obtained by a gravimetric method. The TREO of the mixed rare earth abrasive particles is obtained by "the mass of all rare earth oxides obtained after calcination / the mass of the mixed rare earth abrasive particles before acid dissolution treatment"; the TREO of the niobium abrasive is obtained by "the mass of all rare earth oxides obtained after calcination / the mass of the niobium abrasive before acid dissolution treatment". [The content of each rare earth element in TREO converted into oxides] The test sample is dissolved in acid, and the amount of each rare earth element measured by the ICP-AES method is converted into an oxide value, and the value as an oxide is calculated relative to the value of TREO. [Fluorine atom content] The test sample is alkali-melted, extracted with warm water, and measured with a fluoride ion meter (manufactured by Horiba, Ltd.; ion electrode method).

[Preparation of mixed rare earth oxide raw material] (Mixed rare earth oxide raw material A) A raw ore (rare earth concentrate) containing 47% TREO, 2% medium and heavy rare earths in terms of oxide conversion, and 8% neodymium in terms of oxide conversion is treated by sulfuric acid roasting and solvent extraction to reduce impurities other than rare earth elements to less than 1% by mass and to reduce medium and heavy rare earths to less than 1% by mass in terms of oxide conversion, thereby obtaining a mixed light rare earth compound with adjusted rare earth element content. The mixed light rare earth compound has a content of cerium in TREO (CeO ₂ amount/TREO) calculated as oxide (CeO ₂ ), a content of tantalum in TREO (La ₂ O ₃ ), a content of neodymium in TREO (Nd ₂ O _{3 ), a content of 0.6% by mass (Nd 2 O 3} ), and a content of 0.2% by mass ₍ Pr ₆ O ₁₁ ). The mixed _light rare earth compound is treated with ammonium bicarbonate to obtain a mixed rare earth carbonate. In _the mixed rare earth carbonate, TREO is 49% by mass. The mixed rare earth carbonate was heat treated in a calcining furnace at 800°C for 10 hours in the atmosphere to obtain a mixed rare earth oxide raw material A. Table 1 shows TREO, _CeO2 amount/TREO, _{La2O3 amount} /TREO, _{Nd2O3 amount} /TREO, and _Pr6O11 amount/TREO of the _mixed rare earth oxide raw material A.

(Mixed rare earth oxide raw materials B to E) Mixed rare earth oxide raw materials B to E were prepared in the same manner as mixed rare earth oxide raw material A, using mixed light rare earth compounds, and adjusting the treatment conditions and the heat treatment conditions of mixed rare earth carbonates. TREO, CeO ₂ amount/TREO, La ₂ O ₃ amount/TREO, Nd ₂ O ₃ amount/TREO, and Pr ₆ O ₁₁ amount/TREO of mixed rare earth oxide raw materials B to E are shown in Table 1.

[Preparation of mixed rare earth fluoride raw material] (Mixed rare earth fluoride raw material F) Hydrofluoric acid was added to the mixed light rare earth compound and mixed, and then heat treated at 400°C in the atmosphere for 2 hours to obtain mixed rare earth fluoride raw material F. The TREO, _CeO2 amount/TREO, and fluorine content of the mixed rare earth fluoride raw material F are shown in Table 2.

(Mixed rare earth fluoride raw materials G to I) Mixed rare earth fluoride raw materials G to I were prepared in the same manner as mixed rare earth fluoride raw material F, using mixed light rare earth compounds and adjusting the treatment conditions. TREO, CeO ₂ amount/TREO, and fluorine content of mixed rare earth fluoride raw materials G to I are shown in Table 2.

[Manufacturing of vanadium-based abrasives] A vanadium-based abrasive is manufactured by the following examples and comparative examples. The details of the additives used in the following examples and comparative examples are shown below. ・Additive 1: Sodium tripolyphosphate (Kanto Chemical Co., Ltd.): Molecular weight over 300 ・Additive 2: Sodium salt of polyacrylic acid "POIZ 530" (Kao Corporation): Molecular weight over 300 ・Additive 3: Sodium salt of copolymer of acrylic acid and maleic acid "POIZ 521" (Kao Corporation): Molecular weight over 300 ・Additive 4: Carboxymethylcellulose (Kanto Chemical Co., Ltd.): Molecular weight over 300 ・Additive 5: Crystalline cellulose "Cellulose Microcrystals" (Kanto Chemical Co., Ltd.): Molecular weight over 300

(Example 1) 1000 kg of water, 1400 kg of the mixed rare earth oxide raw material A and the mixed rare earth fluoride raw material F (mass ratio 76:24) were stirred and mixed in a slurry tank, and then mixed and crushed for 17 hours using a wet ball mill (medium: 5 mm diameter zirconia balls) to obtain a uniform mixed solution. The mixed solution was placed in a rotary kiln, dried at 700°C for 1 hour in the atmosphere, and then calcined at 960°C for 4 hours. The calcined body was left to cool, then crushed and graded to obtain mixed rare earth abrasive particles. Calcium hydrogen phosphate as a titanium dissolution inhibitor is added to the mixed rare earth abrasive particles in an amount of 0.1 parts by mass relative to 100 parts by mass of the mixed rare earth abrasive particles, and the mixture is mixed using a stirrer to produce a titanium-based abrasive.

(Examples 2 to 25 and Comparative Examples 1 to 5) In Example 1, except that the mixed rare earth oxide raw material, the mixed rare earth fluoride raw material, the sintering temperature, the titanium dissolution inhibitor, and the additives 1 to 5 are set as described in Tables 3 and 4, the rest is the same operation to produce the titanium-based abrasive.

[Physical property measurement of mixed rare earth abrasive particles and bismuth-based abrasives] The physical property measurements shown below were performed on the mixed rare earth abrasive particles and bismuth-based abrasives manufactured as described above. The results of the physical property measurements are shown in Tables 3 and 4 below.

(Particle size distribution D ₅₀ ) The niobium-based abrasive or mixed rare earth abrasive particles are dispersed in pure water containing a dispersant to prepare the test sample. The particle size distribution of the niobium-based abrasive is measured by the laser diffraction scattering method using a Microtrac particle size analyzer "MT3300II" (manufactured by Nikkiso Co., Ltd.) to obtain the particle size at 50% of the cumulative volume (D ₅₀ ).

(Specific surface area) The specific surface area of niobium-based abrasive or mixed rare earth abrasive particles is measured in accordance with "6.2 Flow method (3.5) One-point method" of JIS R 1626:1996 (Determination of specific surface area of fine ceramic powder by gas adsorption BET method). Nitrogen is used as the adsorbent gas.

[Evaluation of vanadium-based abrasives] The vanadium-based abrasives produced by the above-mentioned embodiments and comparative examples were evaluated as shown below. The evaluation results are summarized in the following Table 5.

(Dissolved ion analysis) The amount of iodine, fluorine, and chlorine dissolved in water when the iodine-based abrasive is dispersed in water is calculated by ICP analysis and IC analysis. [Preparation of samples for ICP analysis and IC analysis] 10 g of the iodine-based abrasive as a slurry component and 40 g of pure water were placed in a 100 mL polyethylene container together with 130 g of zirconia beads with a particle size of 1 mm as beads. The iodine-based abrasive was pulverized using a ball mill at a container rotation speed of 210 rpm for 30 minutes to obtain a mixed solution. 20 mL of the obtained mixed solution was taken and filtered using a membrane filter "SLHN033NS" with a pore size of 0.45 μm (manufactured by Millipore Co., Ltd., Japan), and then filtered using a syringe holder equipped with a membrane filter "VSWP02500" with a pore size of 0.025 μm (manufactured by Millipore Co., Ltd., Japan) to prepare an analytical sample. In addition, ICP and IC analysis were performed using samples within 48 hours after the preparation of the analytical sample.

[ICP analysis] After adding 10 mL of an aqueous solution of nitric acid (70% by mass) and ultrapure water in a volume ratio of 1:1 to 10 mL of the obtained analytical sample, the solution was diluted to 100 mL with ultrapure water to prepare an ICP analytical sample. The absorbance of the ICP analytical sample at a wavelength of 333.749 nm was measured using an ICP emission spectrometer "iCap7000Duo" (manufactured by Thermo Fisher Scientific Co., Ltd.), and the mass concentration of titanium atoms (mg/L) was calculated.

[IC analysis] 10 mL of the obtained analytical sample was diluted 20 times with ultrapure water to prepare an IC analysis sample. The IC analysis sample was measured using an ion chromatography system "ICS-1600" (manufactured by Thermo Fisher Scientific Co., Ltd.) with a solution containing sodium carbonate and sodium bicarbonate, and the mass concentration (mg/L) of fluorine ions and chlorine ions was calculated.

(Evaluation of skin roughening and dermatitis) 10g of the bismuth-based abrasive obtained in the examples and comparative examples and 40g of pure water were placed in a 100mL polyethylene container together with 130g of zirconia beads with a particle size of 1mm. The bismuth-based abrasive was pulverized using a ball mill at a container rotation speed of 210rpm for 30 minutes to obtain a mixed solution containing 20% by mass of the bismuth-based abrasive. The mixed solution was used to verify the occurrence of skin roughening and dermatitis. Specifically, 0.2 ml of the above-mentioned abrasive slurry as the test object was applied to the gauze part of the OK Bandage and allowed to fully penetrate. It was then directly attached to the inner side of each person's forearm, and the state of the skin surface was observed after 30 minutes. If the skin becomes rough and dermatitis progresses, itching or erythema will be observed. Based on this observation, those who did not confirm itching or erythema at all were defined as "unchanged"; those with itching were defined as "slightly worsened"; those who only confirmed erythema were defined as "worsen"; those who could clearly confirm erythema were defined as "obvious worsening", and the scores were given according to the following skin roughness evaluation criteria. [Criteria for judging the effect of inhibiting skin roughening and dermatitis] 0 points: No change 1 point: Slightly worsened 2 points: Worsen 3 points: Significantly worsened

(Polishing Evaluation) Using each of the bismuth-based abrasives obtained in the above-mentioned Examples and Comparative Examples, 48 g of the bismuth-based abrasives and 272 g of pure water were placed in a 500 ml beaker with a rotor of φ8×40 mm, and stirred at 500 rpm for 1 hour using a magnetic stirrer REXIM "RS-1DN" manufactured by AS ONE Co., Ltd., to prepare a polishing slurry having a bismuth-based abrasive content of 15 mass %. Using the polishing slurry, a sample of alkali-free glass for TFT liquid crystal display (50 mm×50 mm×thickness 1.1 mm, polishing area 25 cm ² ) was polished using a single-sided polisher under the following polishing conditions, and the polishing rate and polishing scratches were evaluated. [Grinding conditions] Grinding pad: suede pad, lower platen rotation speed: 260rpm, grinding pressure: 100g/ ^cm2, grinding time: 20 minutes x 3 pieces

Each evaluation method is as follows. [Polishing speed] The thickness of each sample before and after polishing was measured at 5 locations using a micrometer, and the average value of the thickness reduction (ΔT [μm]) was obtained. The average value of [ΔT/polishing time (20 minutes)] for the three samples was set as the polishing speed. [Polishing scratches] The polished sample was observed at a magnification of 50 times using a differential interference microscope ("BX51M" manufactured by Olympus Co., Ltd.) on the polished surface of the sample, and the number of scratches was counted. The average value was obtained for the three samples.

As can be clearly seen from Table 5, the vanadium-based abrasives (Examples 1 to 25) obtained by the specified method with a vanadium dissolution amount of 40 mg/L or less in the mixed solution were confirmed to suppress the occurrence of skin roughening and dermatitis. In addition, the polishing liquid containing the vanadium-based abrasive was confirmed to suppress the occurrence of grinding scratches and enable polishing at a good polishing rate.

Claims (16)

A bismuth-based abrasive material, which is a bismuth-based abrasive material containing mixed rare earth abrasive particles containing bismuth and bismuth, wherein, the content of the bismuth in terms of oxide conversion (TREO) of all rare earth elements is 55.0 mass % or more, 10 g of the bismuth-based abrasive material and 40 g of pure water are placed in a 100 mL polyethylene container together with 130 g of zirconia beads with a particle size of 1 mm as beads, and the bismuth-based abrasive material is pulverized using a ball mill stand at a container rotation speed of 210 rpm for 30 minutes, and the amount of bismuth dissolved in the obtained mixed solution is 40 mg/L or less. The vanadium-based abrasive of claim 1 further contains a vanadium dissolution inhibitor. The niobium-based abrasive of claim 1 is a two-part type, comprising: a first part containing the aforementioned mixed rare earth abrasive particles, and a second part containing a niobium dissolution inhibitor. The vanadium-based abrasive of claim 1, wherein the fluorine atoms are contained in an amount of 0.1 to 10 mass %. The vanadium-based abrasive of claim 1, wherein in the TREO, the content of the vanadium in terms of oxide is 0.01-45.0 mass %. The vanadium-based abrasive of claim 2 or 3, wherein the aforementioned indium dissolution inhibitor is selected from alkali metal carbonates, alkali metal phosphates, alkali metal hydroxides, alkali metal sulfates, alkali metal nitrates, alkali metal organic acid salts, alkaline earth metal carbonates, alkaline earth metal One or more of phosphates of alkali earth metals, hydroxides of alkali earth metals, sulfates of alkali earth metals, nitrates of alkali earth metals, organic acid salts of alkali earth metals, carbonates of ammonium, phosphates of ammonium, hydroxides of ammonium, sulfates of ammonium, nitrates of ammonium, and organic acid salts of ammonium. The indium-based abrasive of claim 6, wherein the indium dissolution inhibitor is at least one selected from the group consisting of alkali earth metal carbonates, alkali earth metal phosphates, alkali earth metal organic acid salts, and alkali metal carbonates. The niobium-based abrasive of claim 2 or 3, wherein the molecular weight of the niobium dissolution inhibitor is 300 or less. The niobium-based abrasive of claim 2 or 3, wherein the niobium dissolution inhibitor is contained in an amount of 0.001 to 0.9 parts by mass relative to 100 parts by mass of the mixed rare earth abrasive particles. A polishing liquid comprises: the vanadium-based abrasive of claim 1 and at least one selected from water and a water-soluble organic solvent. A method for producing a polishing liquid, which is the method for producing a polishing liquid of claim 10, comprising the following step (I), Step (I): mixing the aforementioned cerium-based abrasive with one or more selected from the aforementioned water and the aforementioned water-soluble organic solvent and slurrying them. A method for producing a polishing liquid as claimed in claim 11, wherein the aforementioned niobium-based polishing material contains the aforementioned niobium dissolution inhibitor. A method for producing a polishing liquid, which is the method for producing a polishing liquid of claim 10, comprising the following step (II), Step (II): mixing the aforementioned niobium-based abrasive, the aforementioned niobium dissolution inhibitor, and one or more selected from the aforementioned water and the aforementioned water-soluble organic solvent and slurrying them. A method for producing a polishing liquid, which is the method for producing a polishing liquid of claim 10, comprising the following steps (III) and (IV), Step (III): mixing the aforementioned niobium-based abrasive with one or more selected from the aforementioned water and the aforementioned water-soluble organic solvent to form a slurry; Step (IV): adding the aforementioned niobium dissolution inhibitor to the slurry obtained in the aforementioned step (III) and mixing the mixture. A method for manufacturing a polishing liquid as claimed in claim 14, wherein the aforementioned niobium-based polishing material does not contain the aforementioned dissolution inhibitor. A glass grinding method, which uses the grinding liquid of claim 10 for grinding.