WO2003078313A1 - Process for the preparation of a lime product containing active oxygen - Google Patents
Process for the preparation of a lime product containing active oxygen Download PDFInfo
- Publication number
- WO2003078313A1 WO2003078313A1 PCT/FI2003/000203 FI0300203W WO03078313A1 WO 2003078313 A1 WO2003078313 A1 WO 2003078313A1 FI 0300203 W FI0300203 W FI 0300203W WO 03078313 A1 WO03078313 A1 WO 03078313A1
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- WO
- WIPO (PCT)
- Prior art keywords
- hydrogen peroxide
- lime
- water
- aqueous solution
- solution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B15/00—Peroxides; Peroxyhydrates; Peroxyacids or salts thereof; Superoxides; Ozonides
- C01B15/04—Metal peroxides or peroxyhydrates thereof; Metal superoxides; Metal ozonides; Peroxyhydrates thereof
- C01B15/043—Metal peroxides or peroxyhydrates thereof; Metal superoxides; Metal ozonides; Peroxyhydrates thereof of alkali metals, alkaline earth metals or magnesium or beryllium or aluminium
Definitions
- Literature comprises myriad studies of hydrogen peroxide stabilisation in solution. Stabilisation of hydrogen peroxide in solution is important in pulp bleaching, for instance.
- the solutions contain metal ions (e.g. Fe, Cu and Mn), which catalyse peroxide degradation and cause significant hydrogen peroxide loss.
- metal ions e.g. Fe, Cu and Mn
- Silicate addition J. Pulp and Paper Sci, vol, 12, no 6 (1986), pp. 166- 172
- Silicate addition J. Pulp and Paper Sci, vol, 12, no 6 (1986), pp. 166- 172
- the article states that a mechanism that probably results in stabilisation in solution is based on the ability of silicate to absorb and deactivate metal ions in the solution.
- Magnesium sulphate has also been noted to stabilise hydrogen peroxide efficiently in alkaline solutions (J. Pulp and Paper Sci, vol, 15, no 2 (1989), pp. 45-51). In bleaching solutions, magnesium sulphate has optimal effect together with sodium silicate. The cause of the joint effect of these two stabilisers is not evident, yet one proposed mechanism is the generation of a stable colloid suspension of magnesium silicate, which absorbs transition metal ions.
- Test Bl comparative test. A 35% H 2 0 2 solution was prepared by mixing 105 g of 50%) H 2 0 2 and 45 g of ion-purified water. The pH of the mixture was adjusted by means of HNO 3 (65%) to pH 1. The percentage of H 2 0 2 in the solution obtained was determined.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Agricultural Chemicals And Associated Chemicals (AREA)
Abstract
The invention relates to a method for preparing a lime product containing active oxygen, in which caustic lime is reacted with an aqueous solution of hydrogen peroxide so as to produce a solid lime product containing active oxygen and comprising calcium peroxide and slaked lime, the aqueous solution of hydrogen peroxide containing a water-soluble salt of a non-transition metal, such as magnesium sulfate, and a water-soluble silicate.
Description
Process for the preparation of a lime product containing active oxygen
The invention relates to a method for preparing a lime product containing active oxygen.
Prior art
FI patent application 970208 discloses a method for preparing a lime product containing active oxygen. In this method, caustic lime (CaO) is reacted with an aqueous solution of hydrogen peroxide so as to generate a solid phase containing calcium peroxide and slaked lime. The reaction has the essential feature of not generating any liquid phase as a reaction product. The generated product will thus be dry and usable as such. The product called "oxygen lime" in this previous application is a mixture (Ca02 • Ca (OH)2) of calcium peroxide (Ca02) and calcium hydroxide (Ca (OH)2).
FI 970208 states that oxygen calcium can be prepared by spraying a solution of hydrogen peroxide onto the surface of caustic lime during violent stirring. The oxygen concentration of the product can be controlled by means of the amount of the hydrogen peroxide addition. Caustic lime reacts with hydrogen peroxide forming calcium peroxide, and the water contained in it reacts further with caustic lime into slaked lime (Ca(OH)2). By regulating the amounts of caustic lime and hydrogen peroxide, the reaction can be controlled so as to generate a reaction mixture without any liquid phase.
The following reaction occurs between caustic lime and the solution of hydrogen peroxide:
2 CaO (s) + H202 (1) / H20 (1) → Ca02 (s) + Ca (OH)2 (s)
Oxygen lime is used in agriculture, the food industry and in environmental protection. In these fields of application, oxygen lime is used for disinfection, to boost soil combustion and to enhance the biological activity of the soil. Oxygen lime typically contains 1 to 2 % of active oxygen. Such a product is safe to handle, while still containing active oxygen in a sufficient amount.
The major problem of oxygen lime production is peroxide degradation during the preparation reaction. Up to half of hydrogen peroxide reacting with caustic lime decomposes into water and oxygen without forming calcium peroxide. The water generated by degradation reacts with caustic lime, forming slaked lime. Oxygen escapes into the ambient atmosphere. Consequently, in terms of oxygen lime production economy, it would be of vital importance to find a method allowing the amount of degraded peroxide to be reduced.
Literature comprises myriad studies of hydrogen peroxide stabilisation in solution. Stabilisation of hydrogen peroxide in solution is important in pulp bleaching, for instance. The solutions contain metal ions (e.g. Fe, Cu and Mn), which catalyse peroxide degradation and cause significant hydrogen peroxide loss. On the basis of studies relating to pulp bleaching, various hydrogen peroxide stabilisers have been proposed. Silicate addition (J. Pulp and Paper Sci, vol, 12, no 6 (1986), pp. 166- 172) has achieved a decrease in hydrogen peroxide degradation. The article states that a mechanism that probably results in stabilisation in solution is based on the ability of silicate to absorb and deactivate metal ions in the solution.
Magnesium sulphate has also been noted to stabilise hydrogen peroxide efficiently in alkaline solutions (J. Pulp and Paper Sci, vol, 15, no 2 (1989), pp. 45-51). In bleaching solutions, magnesium sulphate has optimal effect together with sodium silicate. The cause of the joint effect of these two stabilisers is not evident, yet one proposed mechanism is the generation of a stable colloid suspension of magnesium silicate, which absorbs transition metal ions.
Purpose of the invention
The purpose of the invention is thus to provide a method of preparing oxygen lime, which allows reduction of hydrogen peroxide degradation in the reaction step. The method thus achieves higher active oxygen concentration of the product and the loss of hydrogen peroxide will decrease accordingly.
Description of the invention
In tests conducted with various additives, it was surprisingly found that silicate and magnesium act as hydrogen peroxide stabilisers also when hydrogen peroxide reacts with solid CaO. The effect was observed in tests, which showed that oxygen lime
produced by using a stabiliser had a higher active oxygen concentration than that of oxygen lime prepared by the conventional method. This observation was surprising precisely because the reaction includes no liquid phase proper and thus no metal ions. Impurities are on the surface of the solid substance. Supplementary tests showed that a number of other soluble sulphate compounds were efficient together with silicate. These compounds had the common feature of having a cation that did not pertain to transition metals.
In accordance with the invention, a method for producing a lime product containing active oxygen, also called oxygen lime, has thus been provided, in which caustic lime is reacted with an aqueous solution of hydrogen peroxide, generating a solid lime product containing active oxygen and comprising calcium peroxide and slaked lime, the aqueous solution of hydrogen peroxide containing a water-soluble salt of a non-transition metal and a water-soluble silicate.
The solid lime product containing active oxygen prepared in accordance with the invention is dry, i.e. excess water has been eliminated. In accordance with the invention, the water contained in the aqueous solution of hydrogen peroxide, which is not consumed in the chemical reaction, is removed by evaporation under the effect of the reaction heat.
With non-transition metals, the oxidation number remains constant, and is thus unable to cause hydrogen peroxide degradation, contrary to transition metals.
In the lime product containing active oxygen produced in accordance with the invention, the weight ratio of calcium peroxide to slaked lime may vary in the range 1 :50 to 1 :3, preferably in the range 1:20 to 1 :3.
The active oxygen concentration of the lime product containing active oxygen produced in accordance with the invention may be 0.4 to 5.6%, preferably 1-4%.
The cation of the water-soluble salt of said non-transition metal is preferably a sodium, potassium, magnesium, aluminium or ammonium ion, and the anion is preferably a sulphate, formate or acetate. A particularly preferred water-soluble salt of a non-transition metal is sodium, potassium, magnesium, aluminium or ammonium sulphate.
Said water-soluble silicate may be a sodium or potassium silicate, preferably sodium silicate.
Said aqueous solution of hydrogen peroxide preferably contains 0.5 to 5, particularly advantageously 0.8 to 4.5 mmole of a water-soluble salt of a non- transition metal/mole of hydrogen peroxide. The silicate amount may be 0.005-1, preferably 0.01-0.5 and particularly advantageously 0.02 - 0.1 mmole of Si02/mole of hydrogen peroxide.
In one embodiment of the invention, the aqueous solution of hydrogen peroxide reacting with caustic lime is prepared by starting with a stabilising solution, which contains said water-soluble salt of a non-transition metal and said water-soluble silicate, the solution being subsequently added to the aqueous solution of hydrogen peroxide. This stabilising solution may additionally contain an acid, preferably nitric acid, for regulation of the pH of the aqueous solution to a suitable value, preferably a value of approximately 1 to 2.
The aqueous solution of hydrogen peroxide used in the method of the invention contains preferably 30 to 50% by weight, especially advantageously about 35% by weight of hydrogen peroxide. This aqueous solution of hydrogen peroxide has been typically stabilised by means of conventional hydrogen peroxide stabilisers.
The action of the supplementary stabilisation of the invention is probably based on the fact that the stabiliser covers the transition metals present on the surface of the solid substance. In this manner, the surface will have less metal impurity sites catalysing peroxide degradation.
In accordance with the invention, an aqueous solution of hydrogen peroxide can be sprayed on the surface of caustic lime. The reaction temperature may vary in the range 40 to 100 °C.
Oxygen lime prepared in accordance with the invention can be used in agriculture, the food industry and environmental protection, for disinfecting purposes, to boost soil combustion and to enhance the biological activity of the soil, for instance.
The invention is explained in greater detail below by means of examples. The percentages are given as percent by weight, unless otherwise indicated.
Example 1
A supplementary stabilising solution was prepared by mixing 80 g of ion purified H20, 20 g of MgS04, 1 g of sodium silicate and 8 g of HN03 (60%). The sodium silicate solution used in the example consisted of a commercial water glass solution having a solid matter concentration of 36% and a molar ratio Na20:Si02 = 3.3 (Zeopol 33, producer J.M.Huber).
Test Al (comparative test). A 35% hydrogen peroxide solution was prepared by weighing 420 g of normally stabilised 50% hydrogen peroxide solution and 180 g of ion purified water. The percentage of H202 and the pH of this hydrogen peroxide solution were analysed.
A lime sample (100 g of Gotland lime) was weighed in an evaporation dish. While the lime was continuously stirred by hand using a spoon, 67.5 g of a 35% hydrogen peroxide solution was added drop wise from a measuring flask. The addition was performed for 3 minutes. When the solution reacted with lime, a heat generating reaction occurred, resulting in evaporation of excess water.
The sample was homogenised by light stirring. Immediately after the stirring, a sample of the homogenous mixture was taken and the active oxygen concentration of this was analysed.
Test A2. A 35% hydrogen peroxide solution was prepared by weighing 420 g of normally stabilised 50% hydrogen peroxide solution and 178.3 g of ion purified water, and also 1.7 g of the above prepared supplementary stabilising solution containing MgS04. The percentage of H202 and the pH of this hydrogen peroxide solution were analysed. The procedure was the same as in test Al in other respects.
Test A3. The procedure was the same as in test A2 in other respects, but 176.7 g of ion purified water and 3.3 g of the supplementary stabilising solution containing MgS04 were used for the preparation of the 35% hydrogen peroxide solution.
Test A4. The procedure was the same as in test A2 in other respects, but 173.4 g of ion purified water and 6.6 g of the supplementary stabilising solution containing MgS04 were used for the preparation of the 35% hydrogen peroxide solution.
Test A5. The procedure was the same as in test A2 in other respects, but 170 g of ion purified water and 10 g of the supplementary stabilising solution containing MgS04 were used for the preparation of the 35% hydrogen peroxide solution.
Test A6. The procedure was the same as in test A2 in other respects, but 166.8 g of ion purified water and 13.2 g of the supplementary stabilising solution containing MgS0 were used for the preparation of the 35% hydrogen peroxide solution.
The tests comprised analysis of the hydrogen peroxide concentration of the solution before the addition. The pH was measured after the stabilising solution had been added to the hydrogen peroxide solution. The corrected pH value allows for the error in pH measurement caused by the hydrogen peroxide concentration. The H202 concentration of the lime mixture was analysed after the addition. The results of tests A1-A6 are shown in the following table.
Table 1
The tests indicate that the additionally stabilised hydrogen peroxide solution of the invention has better resistance in a situation of preparing oxygen lime than a conventional hydrogen peroxide solution. However, the amount of stabilisers should be sufficient, while not being excessive; in the latter case, they would have a weaker effect.
The tests indicate that supplementary stabilisation achieved an up to about 20% increase in the concentration of active oxygen of the oxygen lime.
Example 2
Diluted (35%) hydrogen peroxide was subjected to supplementary stabilisation by means of several sulphate compounds.
The preparation of supplementary stabilising solutions for tests B2 to B6 was carried out as in table 2. The supplementary stabilising solution prepared for test B2 had the same composition as in example 1. The amount of salt used in the preparation of the remaining solutions was selected so as to have the same S0 concentration in all of them.
Table 2
Test Bl (comparative test). A 35% H202 solution was prepared by mixing 105 g of 50%) H202 and 45 g of ion-purified water. The pH of the mixture was adjusted by means of HNO3 (65%) to pH 1. The percentage of H202 in the solution obtained was determined.
Gotland lime (100 g) was weighed in an evaporation dish. While the lime was continually stirred by hand with a spoon, 67.5 g of hydrogen peroxide solution was added drop wise from a measuring flask. The addition was performed for 3 minutes. The sample was homogenised by light stirring. As the solution reacted with lime, a heat generating reaction took place, whereby excess water evaporated. Immediately
after the addition of hydrogen peroxide solution and homogenisation, the concentration of active oxygen in the mixture was determined.
Test B2. A hydrogen peroxide solution was prepared by mixing 105 g of 50% H202 and 41.7 g of ion-purified water and 3.3 g of the supplementary stabilising solution containing MgS0 of table 2. The pH of the mixture was adjusted by means of HN03 (65%) to pH 1. In other respects, the test was conducted as test B 1.
Test B3. Otherwise the same as test B2, but with the use of 40.5 g of ion-purified water and the 4.5 g of supplementary stabilising solution containing CaS04 of table 2.
Test B4. Otherwise the same as test B2, but with the use of 36.7 g of ion-purified water and the 3.3 g of the supplementary stabilising solution containing Na2S04 of table 2.
Test B5. Otherwise the same as test B2, but with the use of 41.1 g of ion-purified water and 3.9 g of the supplementary stabilising solution containing A12(S0 )3 of table 2.
Test B6. Otherwise the same as test B2, but with the use of 41.6 g of ion-purified water and 3.9 g of the supplementary stabilising solution containing (NH4)2S0 of table 2.
The results obtained in tests B1-B6 are given in table 3.
Table 3
The tests in examples 1 and 2 indicate that an increase in the concentration of active oxygen (= 0.4706 x % of H202) is attained by means of supplementary stabilisation with all the compounds excepting CaS0 , which is very poorly water-soluble.
The method is assumingly viable also with other than sulphate compounds, such as with formates, acetates, etc. This is due to the fact that sulphate as such does not apparently perform an essential task in producing supplementary stabilisation, which is rather due to the joint effect of the cation and the silicate.
Claims
1. A method for preparing a lime product containing active oxygen, characterised in that caustic lime is reacted with an aqueous solution of hydrogen peroxide so as to produce a solid lime product containing active oxygen and comprising calcium peroxide and slaked lime, the aqueous solution of hydrogen peroxide containing a water-soluble salt of a non-transition metal and a water-soluble silicate.
2. A method as defined in claim 1, characterised in that the weight ratio of calcium peroxide to slaked lime in the lime product containing active oxygen is in the range
1 :50 to 1 :3, preferably in the range 1 :20 to 1 :3.
3. A method as defined in claim 1 or 2, characterised in that the lime product containing active oxygen has an active oxygen concentration of 0.4 to 5.6%, preferably 1 to 4%.
4. A method as defined in any of the preceding claims, characterised in that the cation of the water-soluble salt of a non-transition metal is a sodium, potassium, magnesium, aluminium or ammonium ion and the anion is sulphate, formate or acetate.
5. A method as defined in claim 4, characterised in that the water-soluble salt of a non-transition metal is sodium, potassium, magnesium, aluminium or ammonium sulphate.
6. A method as defined in any of the preceding claims, characterised in that the water-soluble silicate is sodium silicate.
7. A method as defined in any of the preceding claims, characterised in that the aqueous solution of hydrogen peroxide contains 0.5 to 5, preferably 0.8 to 4.5 mmole of the water-soluble salt of a non-transition metal/mole of hydrogen peroxide.
8. A method as defined in any of the preceding claims, characterised in that the aqueous solution of hydrogen peroxide contains silicate in a ratio of 0.005 to 1, preferably 0.02 to 0.1 mmole of Si02/mole of hydrogen peroxide.
9. A method as defined in any of the preceding claims, characterised in that the aqueous solution of hydrogen peroxide reacting with caustic lime has been prepared by first preparing a stabilising solution, which contains said water-soluble salt of a non-transition metal and said water-soluble silicate, the solution being subsequently added to the aqueous solution of hydrogen peroxide.
10. A method as defined in claim 9, characterised in that the stabilising solution additionally contains an acid, preferably nitric acid, for regulation of the pH of the aqueous solution of hydrogen peroxide to a value of 1 to 2.
11. A method as defined in any of the preceding claims, characterised in that the aqueous solution of hydrogen peroxide contains 30 to 50% by weight of hydrogen peroxide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2003219194A AU2003219194A1 (en) | 2002-03-18 | 2003-03-18 | Process for the preparation of a lime product containing active oxygen |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI20020502A FI113757B (en) | 2002-03-18 | 2002-03-18 | Process for the preparation of a lime product containing active oxygen |
| FI20020502 | 2002-03-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2003078313A1 true WO2003078313A1 (en) | 2003-09-25 |
Family
ID=8563573
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/FI2003/000203 Ceased WO2003078313A1 (en) | 2002-03-18 | 2003-03-18 | Process for the preparation of a lime product containing active oxygen |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU2003219194A1 (en) |
| FI (1) | FI113757B (en) |
| WO (1) | WO2003078313A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2341449C1 (en) * | 2007-05-23 | 2008-12-20 | Государственное образовательное учреждение высшего профессионального образования "Уфимский государственный нефтяной технический университет" | Method of obtaining anhydrous calcium peroxide |
| US11453587B2 (en) | 2018-11-19 | 2022-09-27 | Lixivia, Inc. | Compositions and methods for production of metal peroxides |
| CN116947081A (en) * | 2023-07-31 | 2023-10-27 | 广州瑞云材料科技有限公司 | Method for removing sulfides from natural calcium carbonate |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI102368B (en) * | 1997-01-17 | 1998-11-30 | Nordkalk Oyj Abp | Process for the preparation of a lime product containing active acid and its use |
| CN1346787A (en) * | 2001-09-26 | 2002-05-01 | 陶华西 | Preparation method of calcium peroxide |
-
2002
- 2002-03-18 FI FI20020502A patent/FI113757B/en not_active IP Right Cessation
-
2003
- 2003-03-18 AU AU2003219194A patent/AU2003219194A1/en not_active Abandoned
- 2003-03-18 WO PCT/FI2003/000203 patent/WO2003078313A1/en not_active Ceased
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI102368B (en) * | 1997-01-17 | 1998-11-30 | Nordkalk Oyj Abp | Process for the preparation of a lime product containing active acid and its use |
| CN1346787A (en) * | 2001-09-26 | 2002-05-01 | 陶华西 | Preparation method of calcium peroxide |
Non-Patent Citations (2)
| Title |
|---|
| DATABASE WPI Week 197335, Derwent World Patents Index; AN 1973-49214U, XP002964933 * |
| DATABASE WPI Week 200253, Derwent World Patents Index; Class E33, AN 2002-491470, XP002964934 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2341449C1 (en) * | 2007-05-23 | 2008-12-20 | Государственное образовательное учреждение высшего профессионального образования "Уфимский государственный нефтяной технический университет" | Method of obtaining anhydrous calcium peroxide |
| US11453587B2 (en) | 2018-11-19 | 2022-09-27 | Lixivia, Inc. | Compositions and methods for production of metal peroxides |
| CN116947081A (en) * | 2023-07-31 | 2023-10-27 | 广州瑞云材料科技有限公司 | Method for removing sulfides from natural calcium carbonate |
| CN116947081B (en) * | 2023-07-31 | 2024-02-13 | 广州瑞云材料科技有限公司 | Method for removing sulfides from natural calcium carbonate |
Also Published As
| Publication number | Publication date |
|---|---|
| FI20020502A0 (en) | 2002-03-18 |
| FI20020502A7 (en) | 2003-09-19 |
| FI113757B (en) | 2004-06-15 |
| AU2003219194A1 (en) | 2003-09-29 |
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