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Method for preparing dicyandiamide and industrial calcium phosphate and carbon from dicyandiamide waste slag

A technology of dicyandiamide waste residue and dicyandiamide, applied in chemical instruments and methods, preparation of organic compounds, phosphorus compounds, etc., can solve problems such as waste of raw materials, environmental pollution, and insufficient use of dicyandiamide residue functions, and achieve Less equipment investment, simple method, good economic and environmental benefits

Inactive Publication Date: 2011-08-31
张胜勇
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For a long time, dicyandiamide waste residue has been mainly used as cement and soil improvement, or stacked randomly, which not only wastes raw materials, but also pollutes the environment
[0007] People also actively seek the comprehensive treatment and utilization method of dicyandiamide waste residue, as application number is 00113513.9, the Chinese patent utilizes dicyandiamide waste residue to produce lime, and application number is 200410022909.3 Chinese patent utilization dicyandiamide waste residue to produce solid fuel, yet, These patents have only utilized a small number of active ingredients in the dicyandiamide waste residue, and have not fully utilized the function of the dicyandiamide waste residue

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A kind of method utilizing dicyandiamide waste residue to prepare dicyandiamide, industrial calcium phosphate and charcoal, comprises following specific steps:

[0021] (1) Weigh 500 kg of dicyandiamide waste residue, mix the dicyandiamide waste residue with water, and separate the insoluble part. The amount of water used should be sufficient to obtain an aqueous solution of cyanamide with a mass concentration of 3%, as well as calcium carbonate and charcoal. mixture, which also contains a small amount of silicate;

[0022] (2) adjusting the pH of the cyanamide aqueous solution to be alkaline, and performing binary polymerization on the cyanamide aqueous solution at 120° C. to obtain a dicyandiamide product;

[0023] (3) Fully react the mixture of calcium carbonate and carbon with excess dilute hydrochloric acid, at this time, calcium carbonate reacts with hydrochloric acid to generate calcium chloride and CO 2 gas, and carbon does not react with hydrochloric acid, nor...

Embodiment 2

[0027] A kind of method utilizing dicyandiamide waste residue to prepare dicyandiamide, industrial calcium phosphate and charcoal, comprises following specific steps:

[0028] (1) Weigh 500 kg of dicyandiamide waste residue, mix the dicyandiamide waste residue with water, and separate the insoluble part. The amount of water used should be sufficient to obtain an aqueous solution of cyanamide with a mass concentration of 3%, as well as calcium carbonate and charcoal. mixture, which also contains a small amount of silicate;

[0029] (2) adjusting the pH of the cyanamide aqueous solution to be alkaline, and performing binary polymerization on the cyanamide aqueous solution at 120° C. to obtain a dicyandiamide product;

[0030] (3) Fully react the mixture of calcium carbonate and carbon with excess dilute hydrochloric acid, at this time, calcium carbonate reacts with hydrochloric acid to generate calcium chloride and CO 2 gas, and carbon does not react with hydrochloric acid, nor...

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PUM

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Abstract

The invention provides a method for preparing dicyandiamide and industrial calcium phosphate and carbon from dicyandiamide waste slag. The method comprises the following steps of: mixing the dicyandiamide waste slag and water, and separating out an insoluble part to obtain aqueous solution of cyanogenamide and a mixture of calcium carbonate and carbon; performing binary polymerization on the aqueous solution of cyanogenamide to obtain a dicyandiamide product; fully reacting the mixture of the calcium carbonate and the carbon with excessive dilute hydrochloric acid to obtain solution of calcium chloride and carbon filter cakes; washing, drying and crushing the carbon filter cakes to obtain the industrial carbon; fully reacting the solution of calcium chloride with phosphoric acid, and filtering to obtain a calcium phosphate precipitate and hydrochloric acid solution; and drying and crushing the calcium phosphate precipitate to obtain the calcium phosphate product. The method is simple, equipment investment is low, the product yield is high, and the method has good economic and environmental benefits.

Description

technical field [0001] The invention relates to the technical field of comprehensive utilization and treatment of industrial three-waste dicyandiamide residue, in particular to a method for preparing dicyandiamide, industrial calcium phosphate and charcoal by using dicyandiamide residue. Background technique [0002] Lime nitrogen method: Lime nitrogen and water are hydrolyzed, and the suspended calcium cyanamide hydrogen hydrolyzate obtained from the reaction is filtered under reduced pressure to remove the calcium hydroxide filter residue, and the carbon dioxide produced by the decomposition of limestone is passed into the filtrate for decalcification reaction to generate cyanamide Liquid, polymerized under alkaline conditions, and then filtered, cooled to crystallize, separated and dried to obtain dicyandiamide. Its chemical reaction equation is: [0003] 2CaCN 2 +2H 2 O→Ca(HCN 2 ) 2 +Ca(OH) 2 [0004] Ca(HCN 2 ) 2 +CO 2 +H 2 O→2NH 2 CN+CaCO 3 [0005] 2NH ...

Claims

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Application Information

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IPC IPC(8): C07C279/28C07C277/08C01B31/02C01B25/32
Inventor 张胜勇
Owner 张胜勇