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Method for preparing light calcium carbonate and co-producing ammonium sulfate from phosphogypsum

A light calcium carbonate, phosphogypsum technology, applied in the direction of calcium carbonate/strontium/barium, ammonium sulfate, solid waste removal, etc., can solve the problems of high cost and long process flow, avoid secondary pollution, The effect of short process flow

Active Publication Date: 2011-03-30
HEFEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] 1. Through the reaction (2), although the problem of removing insoluble impurities is better solved, it also brings the generated CO 2 issues of purification and reuse;
[0013] 2. The process includes strong acid leaching and two carbonization reactions, the process is long, the cost is high, and there is secondary pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038]The method for preparing light calcium carbonate co-production ammonium sulfate by phosphogypsum in the present embodiment is to operate as follows:

[0039] a. Phase transfer reaction

[0040] Stir and heat the sodium gluconate solution with a mass percentage of 10% to 25°C, the stirring speed is 300r / min, adjust the pH value to 10 with 25% ammonia water by mass percentage, and then add phosphogypsum, phase transfer agent and phosphogypsum The molar ratio of calcium sulfate is 3.5, and the reaction is stirred at a constant temperature for 0.5 hour; after the reaction is completed, the soluble calcium ion solution is obtained by filtering at room temperature;

[0041] b. Precipitation reaction

[0042] Stir and heat the soluble calcium ion solution obtained in step a to 60°C at a stirring speed of 300r / min, then add NH 4 HCO 3 Mixed solution with ammonia water, where NH 4 HCO 3 The molar ratio with ammonia water is 1:1, and the added amount is HCO 3 - with Ca 2+ ...

Embodiment 2

[0046] The method for preparing light calcium carbonate co-production ammonium sulfate by phosphogypsum in the present embodiment is to operate as follows:

[0047] a. Phase transfer reaction

[0048] Stir and heat the sodium lactate solution with a mass percentage of 60% to 40°C, the stirring speed is 200r / min, adjust the pH value to 12 with 25% ammonia water by mass percentage, and then add phosphogypsum, phase transfer agent and calcium sulfate in phosphogypsum The molar ratio is 5, and the reaction is stirred at a constant temperature for 2 hours; after the reaction is completed, the soluble calcium ion solution is obtained by filtering at room temperature;

[0049] b. Precipitation reaction

[0050] Stir and heat the soluble calcium ion solution obtained in step a to 90°C at a stirring speed of 200r / min, then add NH 4 HCO 3 Mixed solution with ammonia water, where NH 4 HCO 3 The molar ratio with ammonia water is 1:1, and the added amount is HCO 3 - with Ca 2+ The ...

Embodiment 3

[0054] The method for preparing light calcium carbonate co-production ammonium sulfate by phosphogypsum in the present embodiment is to operate as follows:

[0055] a. Phase transfer reaction

[0056] Stir and heat the sodium citrate solution with a mass percentage of 30% to 60°C, with a stirring speed of 100r / min, adjust the pH value to 7 with 25% mass percentage of ammonia water, and then add phosphogypsum, phase transfer agent and phosphogypsum The molar ratio of calcium sulfate is 2, and the reaction is stirred at a constant temperature for 3 hours; after the reaction is completed, the soluble calcium ion solution is obtained by filtering at room temperature;

[0057] b. Precipitation reaction

[0058] The soluble calcium ion solution obtained in step a is stirred and heated to 40° C., the stirring speed is 50 r / min, and then solid (NH 4 ) 2 CO 3 , the amount added is CO 3 2- with Ca 2+ The molar ratio is 1.2, and the reaction is stirred at constant temperature for ...

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Abstract

The invention discloses a method for preparing light calcium carbonate and co-producing ammonium sulfate from phosphogypsum, which comprises the steps of: firstly, converting phosphogypsum into a soluble calcium ion solution through phase transfer reaction; secondly, adding a carburizer in the soluble calcium ion solution, settling and separating to obtain calcium carbonate and filtrate; and thirdly, cooling and crystallizing or evaporating the filtrate to obtain the ammonium sulfate. The invention has the advantages of short process procedure and no need of strong acid leaching and twice carbonization, and avoids the secondary pollution of CO2 to the environment; and the prepared light calcium carbonate accords with the requirement on national corresponding product standards and lays the research foundation for the industrialized massive production.

Description

1. Technical field [0001] The invention relates to the comprehensive utilization of industrial by-product gypsum, in particular to the comprehensive utilization of phosphogypsum waste residues in phosphate fertilizer plants, specifically a new method for preparing light calcium carbonate and co-producing ammonium sulfate from phosphogypsum. 2. Background technology [0002] The main component of phosphogypsum is CaSO 4 2H 2 O, also contains a small amount of SiO 2 、Al 2 o 3 , Fe 2 o 3 , CaO, MgO, trace heavy metal ions and undecomposed phosphate rock powder, P 2 o 5 , F - and free acids and other impurities. [0003] About 4 to 5 tons of phosphogypsum are produced for every ton of phosphoric acid produced. The annual discharge of phosphogypsum by my country's phosphorus chemical industry is about 50 million tons, accounting for more than 70% of the industrial by-product gypsum, and it is still growing at a rate of 15% per year. Due to the huge amount of phosphogyps...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/18C01C1/24B09B3/00
Inventor 杨保俊王百年陈曦张先龙陈祥迎柴多里杨彦
Owner HEFEI UNIV OF TECH
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