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Method for preparing calcium hydroxide with high purity and high activity

A calcium hydroxide, high-activity technology, applied in the direction of calcium/strontium/barium oxide/hydroxide, etc., can solve the problems of difficult separation, large quantities, etc., and achieve the effect of easy removal of impurities

Inactive Publication Date: 2008-09-03
WUHAN INSTITUTE OF TECHNOLOGY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In 1998, U.S. Patent No. 5,846,500 reported a method for preparing calcium carbonate precipitation by using impurity-containing calcium hydroxide, diluting the impurity-containing calcium hydroxide with water to below the saturation concentration of calcium hydroxide, filtering out insoluble solids, and then Calcium carbonate precipitate with high purity is obtained by carbon dioxide carbonization method, but this method requires a large amount of water and is difficult to separate

Method used

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  • Method for preparing calcium hydroxide with high purity and high activity

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Take the content of CaO as 76.42wt.%, Fe 2 O 3 The content is 1.00wt.%, Al 2 O 3 40g quicklime sample with a content of 0.12wt.% and a MgO content of 2.74wt.%, add 80ml of water and stir for digestion, continue stirring, add 200ml of hydrochloric acid with a concentration of 18wt.% to dissolve until there is no suspended matter in the solution, filter, and filter it in the filtrate Add 50ml of concentrated ammonia water (concentration of 25wt.%), the pH of the solution reaches 12.5, keep it at 80°C for 2h, filter with suction, add 260ml of 20wt.% ammonium carbonate solution to the filtrate while stirring, and keep it at 80°C. Let stand for 2h, filter by suction, and wash the calcium carbonate obtained until there is no Cl in the filtrate - It was detected, dried at 120°C and calcined at 930°C for 1 hour to obtain calcium oxide. The prepared calcium oxide is digested at a water-to-calcium mass ratio of 0.6 to obtain high-purity and high-activity calcium hydroxide.

[0035] A...

Embodiment 2

[0037] Take the same raw material as in Example 1, after stirring and digesting, dissolving in hydrochloric acid, and filtering, add 21ml of concentrated ammonia water (concentration of 25wt.%) to the filtrate, the pH of the solution reaches 11.2, and other treatment processes are the same as in Example 1, to obtain high Purity and high activity calcium hydroxide.

[0038] After testing, the obtained intermediate products and final products, in which the whiteness of calcium carbonate is 103.2, the crystal grain size is below 5μm; the CaO content in the obtained CaO product is 98.72wt.%, the content of MgO is 0.68wt.%, Fe The content of Al oxides are all outside the detection range, the yield of CaO is 99.33wt.%, and the activity is 412ml; high purity Ca(OH) after digestion 2 Its whiteness is 100.3.

Embodiment 3

[0040] Take the same raw materials as in Example 1, after stirring and digesting, dissolving in hydrochloric acid, and filtering, add 13ml of concentrated ammonia (concentration of 25wt.%) to the filtrate, and the pH of the solution will reach 10.0. The other processing procedures are the same as in Example 1, to obtain high Purity and high activity calcium hydroxide.

[0041] After testing, the obtained intermediate products and final products, in which the whiteness of calcium carbonate is 102.3, the crystal grain size is about 5μm; the CaO content in the obtained CaO product is 98.13wt.%, the content of MgO is 0.95wt.%, Fe The content of Al oxides are all outside the detection range, the yield of CaO is 99.37wt.%, and the activity is 369ml; high purity Ca(OH) after digestion 2 Its whiteness is 98.1.

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Abstract

The invention relates to a preparation method of high purity and high activity calcium hydroxide from common quicklime, which includes: (1) digesting the quicklime; (2) dissolving into the hydrochloric acid; (3) separating the impurity ions; (4) precipitating Ca<2+>; (5) calcining at high temperature; and (6) digesting to obtain high purity and high activity calcium hydroxide. The method has the advantages that: (1) the method has wide application range, the raw material quicklime containing impurities such as Si, Fe, Mg and Al is applicable to the inventive preparation, and CaO and Ca(OH)2 have a high purity; (2) at the same time the method can conveniently and completely remove multiple impurities by adjusting the pH value of the solution to greater than 11 with the ammonia; and (3) the whiteness of the fabricated calcium carbonate is more than 100, and the activity of calcium oxide made by sintering is more than 400ml.

Description

Technical field [0001] The invention relates to a preparation method for preparing high-purity and high-activity calcium hydroxide by using ordinary quicklime. Background technique [0002] The domestic production of high-purity calcium hydroxide is not much, and its quality is mostly controlled by reference to the indicators in the chemical reagent standard, and the high-purity calcium hydroxide required in industry usually has higher requirements. Chinese patent CN 1056474A discloses a method for producing high-activity and high-purity calcium hydroxide, by controlling the water-to-calcium ratio, digestion temperature, and digestion pressure in the digestion process, and by improving the calcination process, and in the process Before digestion and after separation, it is screened twice, so that the activity of the product is more than 300ml, the content of CaO is more than 72%, the content of impurity is less than 1.7%, and the yield is more than 95%. [0003] my country's exis...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/02C04B2/04
Inventor 池汝安颜钦武丁春华张正文饶发明
Owner WUHAN INSTITUTE OF TECHNOLOGY
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