Method for recovering high purity calcium hydrogen phosphate in sulfur acid-containing waste phosphoric acid

A technology of calcium hydrogen phosphate and waste phosphoric acid, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve problems such as waste of resources, pollution, public hazards, etc., and achieve the effect of low cost and simple process

Inactive Publication Date: 2014-04-23
JIANGSU XIAOCHUN NEW MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the method of lye neutralization and waste residue landfill is adopted, a large amount of sludge containing phosphoric acid will be produced, which will increase the cost of landfill and even cause public nuisance; when the method o

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Add waste phosphoric acid 100g in 500 milliliter four-necked bottle, wherein contains Al(H 2 PO 4 ) 3 It is about 2g, containing 18.4g of sulfuric acid and 36.5g of phosphoric acid.

[0018] Step 1, get above-mentioned waste phosphoric acid. Add 100g of tap water, and add 0.5g of activated carbon powder to the waste phosphoric acid containing sulfuric acid at a temperature of 20°C with stirring, and filter after fully adsorbing to remove oil, mechanical impurities and heavy metals;

[0019] Step 2, the first stage of neutralization: under the condition of reaction temperature of 20°C and stirring, slowly add 190g of calcium carbonate suspension (containing about 19g of calcium carbonate), filter to obtain calcium sulfate dihydrate and aluminum phosphate, At the same time, 227g of clear phosphoric acid-containing filtrate and 55g of filter cake of calcium sulfate dihydrate containing aluminum phosphate were obtained (the drying loss at 105°C was about 40%, that is, th...

Embodiment 2

[0028] Add waste phosphoric acid 100g in 500 milliliter four-necked bottle, wherein contains Al(H 2 PO 4 ) 3 It is about 2g, containing 18.4g of sulfuric acid and 36.5g of phosphoric acid.

[0029] Step 1, get above-mentioned waste phosphoric acid. Add 100g of tap water, add 0.5g of activated carbon powder to the waste phosphoric acid containing sulfuric acid at a temperature of 50°C and stir, and filter after sufficient adsorption to remove oil, mechanical impurities and heavy metals;

[0030] Step 2, the first stage of neutralization: under the condition of reaction temperature of 50°C and stirring, slowly add 42g of calcium carbonate suspension (containing about 21g of calcium carbonate), filter to obtain calcium sulfate dihydrate and aluminum phosphate, At the same time, 179g of clear phosphoric acid-containing filtrate and 55g of filter cake of calcium sulfate dihydrate containing aluminum phosphate were obtained (the drying loss at 105°C was about 40%, that is, the wa...

Embodiment 3

[0039] Add waste phosphoric acid 100g in 500 milliliter four-necked bottle, wherein contains Al(H 2 PO 4 ) 3 It is about 2g, containing 18.4g of sulfuric acid and 36.5g of phosphoric acid.

[0040] Step 1, get above-mentioned waste phosphoric acid. Add 100g of tap water, and add 0.5g of activated carbon powder to the waste phosphoric acid containing sulfuric acid at a temperature of 20°C with stirring, and filter after fully adsorbing to remove oil, mechanical impurities and heavy metals;

[0041] Step 2, the first stage of neutralization: at a reaction temperature of 20°C and stirring, slowly add 468g of calcium hydroxide emulsion (containing about 14g of calcium hydroxide), filter to obtain calcium sulfate dihydrate and aluminum phosphate, At the same time, 613g of clear phosphoric acid-containing filtrate and 55g of filter cake of calcium sulfate dihydrate containing aluminum phosphate were obtained (the drying loss at 105°C was about 40%, that is, the water content was ...

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Abstract

The invention discloses a method for recovering high purity calcium hydrogen phosphate in sulfur acid-containing waste phosphoric acid, which comprises the following processes: adding 0.5% of active carbon powder in the sulfur acid-containing waste phosphoric acid, filtering and adding excessive calcium carbonate suspending liquid or a calcium hydrate emulsion, filtering to obtain dihydrate calcium sulfate and aluminium phosphate, adding calcium with theoretical amount of 0.95-1.1 mole time required by phosphoric acid in the obtained filtrate with the forms of calcium carbonate suspending liquid and the calcium hydrate emulsion, filtering and drying to obtain high purity dihydrate calcium hydrogen phosphate; adding purified water in the obtained high purity dihydrate calcium hydrogen phosphate, beating, controlling the concentration of the solid content at 10-30%, heating a slurry to the temperature of 90-100 DEG C, stirring and aging for 0.5-1.5 hours, performing solid-liquid separation, and drying to obtain the high purity dicalicium phosphate anhydrous. The method has the advantages of simple process and low cost, and effectively uses sulfuric acid and phosphoric acid in waste acid, and reduces the harm on environment.

Description

technical field [0001] The invention relates to a treatment method for chemical waste, in particular to a method for recovering high-purity calcium hydrogen phosphate from waste phosphoric acid containing sulfuric acid, and belongs to the technical field of comprehensive utilization of three wastes. Background technique [0002] When using phosphoric acid-sulfuric acid system polishing solution to chemically polish high-grade aluminum materials, the long-term use of the polishing solution in the aluminum oxidation production process will lead to the accumulation of aluminum components. When the aluminum content in phosphoric acid reaches a certain value, it will be discharged as waste phosphoric acid , this discharged waste phosphoric acid contains Al(H 2 PO 4 ) 3 About 0.5-2.5% (weight percent concentration, the same below), containing about 10-30% of sulfuric acid, and about 30-50% of phosphoric acid. The general way to deal with this chemical polishing solution is to a...

Claims

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Application Information

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IPC IPC(8): C01B25/32
Inventor 朱容均朱晓冰
Owner JIANGSU XIAOCHUN NEW MATERIAL CO LTD
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