JP2012183461A - Process for producing perlite filter aid - Google Patents

Abstract

Disclosed is a method for producing a pearlite filter aid that is excellent in filtration speed and particularly suitable for filtration of foodstuffs.
The method for producing a pearlite filter aid according to the present invention is characterized in that 4-20 wt% NaOH aqueous solution is attached to pulverized pearlite and then baked at 400-800 ° C. The firing time is preferably 30 to 60 minutes. Furthermore, if the said baking temperature is 550-650 degreeC, it will become a perlite filter aid suitable for foodstuffs or a pharmaceutical.
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Description

  The present invention relates to a method for producing a pearlite filter aid that is excellent in filtration rate and is particularly suitable for filtration of foodstuffs, pharmaceuticals and the like.

  Perlite can be produced by foaming and firing pearlite, pinestone, etc., and pulverizing them. It is lightweight and has a lot of bubbles. It is a soil conditioner, mortar material, lightweight aggregate, inorganic thermal insulation, filtration. Used for auxiliaries.

  As a prior art relating to pearlite, Patent Document 1 below discloses that a softening agent that is sodium hydroxide is attached to the surface of pearlite fine particles obtained by pulverizing and classifying soft pearlite rough stone, A method for producing a large particle size pearlite foam characterized by foaming is disclosed, and it is described that this pearlite foam is used for soil improvement materials, mortar materials and the like.

Further, in the following Patent Document 2, 100 parts by weight of pearlite and 3 to 20 parts by weight of sodium hydroxide are blended, and the mixture is stirred and mixed in the presence of 5 to 50 parts by weight of water at room temperature or in a heated state. Is then heat-cured in a dryer at 80 to 200 ° C., and a method for producing a pearlite cured product having a density of 0.2 to 0.6 g / cm ³ is disclosed. It is described that it is used for building interior materials, ceiling materials, heat insulation and heat insulation materials.

JP-A-9-263460 Japanese Patent No. 3398544

  However, the pearlite produced by the production methods described in Patent Documents 1 and 2 is mainly used for building materials and has not been excellent in filtration performance. Moreover, even when used as a filter aid, the pH value of the filtrate is high, which is unsuitable for filtering substances to be taken or applied to the human body such as foods and pharmaceuticals.

  Then, the objective of this invention is providing the manufacturing method of the pearlite filter aid excellent in the filtration speed | rate and especially suitable for filtration of foodstuffs.

  The method for producing a pearlite filter aid of the present invention is characterized in that a 4 to 20 wt% NaOH aqueous solution is attached to pulverized pearlite and then baked at 400 to 800 ° C.

  The pearlite filter aid produced by the method for producing the pearlite filter aid of the present invention has an excellent filtration rate. In addition, since the filtrate does not easily become alkaline, the filtrate is particularly suitable for filtering substances that come into contact with the human body, such as foods and pharmaceuticals.

It is the schematic which showed an example of the PFR measuring apparatus. It is the schematic enlarged view which showed the base part of the PFR measuring apparatus of FIG. It is the schematic enlarged view which showed the measuring method of the filtration time in the PFR measuring apparatus of FIG.

  Hereinafter, this invention is demonstrated based on one Embodiment of the manufacturing method of a pearlite filter aid. However, the scope of the present invention is not limited to this embodiment.

The method for producing a pearlite filter aid according to an embodiment of the present invention is characterized in that a 4 to 20 wt% NaOH aqueous solution is attached to pulverized pearlite and then baked at 400 to 800 ° C. Instead of NaOH, hydroxides such as KOH and Ca (OH) ₂ can also be used.

As the pearlite used in the present invention, conventional pearlite can be used. For example, natural glass such as pearlite or pinestone can be crushed and heated to be foamed.
In the present invention, pulverized pearlite is used. This pulverization can be performed with a crusher or the like, and the average particle diameter (D50) of the pulverized pearlite is preferably 10 μm to 30 μm, the maximum particle diameter is preferably 100 μm or less, and the minimum particle diameter is preferably 1 μm or more. The particle diameter can be measured by a low tap method.
As the pulverized pearlite, commercially available pearlite manufactured by Mitsui Mining & Smelting Co., Ltd. can be used.

The NaOH aqueous solution used in the present invention has a concentration of 4 to 20 wt%. In this invention, this NaOH aqueous solution is made to adhere to the grind | pulverized pearlite. This adhesion can be performed by spraying with a sprayer. Moreover, it can also carry out by throwing these into mixers, such as a ribbon mixer, a muller mixer, a kneader, and a Pag mill, and stirring and mixing.
The blending ratio of the pulverized pearlite and the NaOH aqueous solution at this time is not particularly limited, but is 30 to 50 parts by weight, preferably 35 to 45 parts by weight with respect to 100 parts by weight of pearlite.
Moreover, in this invention, KOH and Ca (OH) ₂ aqueous solution can be used with the processing amount of the same alkali metal equivalent instead of NaOH aqueous solution.

  In the present invention, an aqueous NaOH solution is attached to pearlite and then baked. This baking is performed at 400 to 800 ° C, preferably 500 to 700 ° C, more preferably 550 to 650 ° C. This firing is preferably performed for 30 minutes to 60 minutes, and can be performed in an air atmosphere using a firing furnace or the like.

The pearlite thus produced is suitable as a filter aid and has an excellent filtration rate. In addition, since the filtrate does not easily become alkaline, it is particularly suitable for filtration in the food sector such as sugar and edible oil refining, soft drinks, and sake brewing, and in the pharmaceutical sector such as disinfectants, eye drops, tablets, syrups, and supplements. It is suitable.
In addition to using this pearlite in the form of powder obtained by the above method, the powder is kneaded with a binder such as cellulose or acrylic resin and used in the form of blocks or pellets. You can also

  An embodiment of the present invention will be described below. However, the scope of the present invention is not limited to this example.

≪Sample preparation≫
The pearlite filter aids of Samples 1 to 15 were prepared as shown below.
Samples 1 to 15 used pearlite manufactured by Mitsui Mining & Smelting Co., Ltd. as pulverized pearlite. The average particle size (D50) of this pearlite was 25 μm, the minimum particle size was 1 μm, and the maximum particle size was 100 μm. This particle size is due to the low tap method.
First, sample 1 used this pearlite as it was.
Samples 2 to 15 were prepared by spraying an aqueous NaOH solution onto the pearlite and firing it.
More specifically, 20 g of NaOH aqueous solution is sprayed with a sprayer while stirring so as to adhere as uniformly as possible to the surface with respect to 50 g of the above pearlite, and baked for 30 to 60 minutes in a baking furnace set to the temperature shown in Table 1 below. Samples 2 to 15 were produced. The concentration of the sprayed NaOH aqueous solution is as shown in Table 1 below.

≪Evaluation≫
Samples 1 to 15 were used to evaluate appearance, filtration rate, and pH.

<Appearance>
The appearance of Samples 1 to 15 was visually observed. Samples 1 to 14 were sandy and evaluated as “◯”. Sample 15 was agglomerated by firing and evaluated as “x”.

<Filtration speed>
The PFR (Permebilty Flow Rate) of samples 1 to 14 was measured, and the filtration rate was evaluated. Regarding sample 15, as described above, the filtration rate could not be measured because it aggregated by firing.

PFR was measured by the following procedures (1) to (10).
(1). An apparatus as shown in FIG. 1 is prepared. In FIG. 1, reference numeral 1 is a permeability assembly, reference numeral 2 is a vacuum pump, reference numeral 3 is a vacuum control unit, reference numeral 4 is a 2L filtration bottle, reference numeral 5 is a 5L filtration bottle, reference numeral 6 is a permeability tube, reference numeral 7 is a stop. A cock, 8 is a base, and 9 is a lock ring.
(2). The stop cock 7 of the permeability assembly 1 is closed and the vacuum pump 2 is started.
(3). As shown in FIG. 2, after placing the filter paper 11 on the 20 mesh wire mesh 10 in the base 8, the permeability tube 6 is set on the base 8 and the lock ring 9 is tightened.
(4). 2.00 g of each sample 1-12 is weighed into a weighing pan and placed in a beaker 12. 50 ml of purified water is weighed with a graduated cylinder, 25 ml of which is placed in the beaker 12.
(5). A small amount of purified water from the graduated cylinder is poured into the tube 6 and the filter paper 11 is moistened.
(6). The inside of the beaker 12 is stirred to form a slurry, which is poured into the tube 6.
(7). Rinse the beaker 12 with purified water in the graduated cylinder and pour it into the tube 6. At this time, as shown in FIG. 3, the top mark (24 ml line) (reference numeral 13) of the tube 6 is exceeded.
(8). Open the stopcock 7, start filtration, start the stopwatch when the lower part of the meniscus 14 passes the top mark, measure the time to filter 8ml, that is, the time T (s) to pass the 16ml line (symbol 15) To do.
(9). When the filtration is completed, the cake 16 on the filter paper 11 is dehydrated and the stopcock 7 is closed. And the volume V (ml) of a cake is measured by ... to 0.1 ml unit.
(10). The measured time T and volume V are applied to the following formula 1 to calculate PFR.

  PFR (%) = 100 × √ ((V / T) /0.288) Equation 1

The results are shown in Table 1 above.
A PFR reference sample having an average particle size (D50) of 20 μm was used, and the same filtration rate as 100 was used.

<PH>
The pH of the filtrate stored in the 5 L filtration bottle 5 at the time of the PFR measurement was measured with a pH meter.
The results are shown in Table 1 above.

≪Result≫
As a result of the filtration rate, it was determined that a PFR of 300 or more was good.
Samples 4, 5, 7-9, 11-14 gave good results. These had NaOH aqueous solution density | concentration of 4-20 wt%, and the calcination temperature was 400-800 degreeC.
As a result of the pH measurement, it was determined that the pH was 9.0 or less.
Samples 1, 5, 8, 9, 12, and 13 gave good results. Among these, samples 5, 8, and 12 also had good PFR results.
These had a firing temperature of 600 ° C.

The pearlite filter aid had good filtration rate when fired at 400-800 ° C. after adhering 4-20 wt% NaOH aqueous solution to the pulverized pearlite.
Among them, those having a calcination temperature of about 550 to 650 ° C., which is around 600 ° C., can suppress the pH of the filtrate to 9.0 or less, and are expected to be suitable for the filtration of foodstuffs and pharmaceuticals.

1 (permeability assembly), 2 (vacuum pump), 3 (vacuum control unit), 4 (2L filtration bottle), 5 (5L filtration bottle), 6 (permeability tube), 7 (stopcock), 8 (base ), 9 (lock ring), 10 (wire mesh), 11 (filter paper), 12 (beaker), 13 (top mark), 14 (meniscus), 15 (16 ml line), 16 (cake)

Claims (4)

  A method for producing a pearlite filter aid, comprising attaching a 4 to 20 wt% NaOH aqueous solution to pulverized pearlite and then firing at 400 to 800 ° C.   The method for producing a pearlite filter aid according to claim 1, wherein the firing time is 30 to 60 minutes.   The method for producing a pearlite filter aid according to claim 1 or 2, wherein the firing temperature is 550 to 650 ° C. The method for producing a pearlite filter aid according to any one of claims 1 to 3, wherein the pearlite filter aid is used for foods and / or pharmaceuticals.

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