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Comprehensive utilization method of cyanamide waste residue

A waste slag and cyanamide technology, applied in the direction of chemical instruments and methods, carbon compounds, carboxylate preparation, etc., can solve the problems of low quality of calcium carbonate or lime and high processing cost, and achieve low processing cost, simple process, and improved The effect of added value

Inactive Publication Date: 2013-04-03
宁夏兴平精细化工股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The purpose of the above-mentioned patents is to control dicyandiamide industrial waste residue and reduce environmental pollution, but there are high processing costs, or the quality of calcium carbonate or lime produced is also low, so most of the existing dicyandiamide manufacturers treat it as industrial waste

Method used

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  • Comprehensive utilization method of cyanamide waste residue

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Weigh 1000g of waste residue (moisture content 38%) and add it to a 2000ml beaker, slowly add 1300g of 30% hydrochloric acid, stir while adding, slowly release carbon dioxide gas (about 120 liters), after the dropwise addition, measure pH = 1.6. Suction filtration, drying to obtain 90g of black filter residue (95% is carbon element through elemental analysis). Heat the filtrate to 30-70°C, adjust the pH to 8.5 with an appropriate amount of calcium hydroxide, let it stand still, filter, evaporate and concentrate to remove free water, crystallize, and dry (about 180-200°C) to obtain 760g of calcium chloride dihydrate.

Embodiment 2

[0047]Weigh 2002g of waste residue (moisture content 37.5%) and add it to a 5000ml beaker, slowly add 2650g of 30% hydrochloric acid, stir while adding, slowly release carbon dioxide gas (about 230 liters), after the dropwise addition, measure pH = 1.8. Suction filtration, drying to obtain 190g of black filter residue (the main component is carbon). Heat the filtrate to 60-80°C, adjust the pH to 8.8 with an appropriate amount of calcium hydroxide, let it stand still, filter, evaporate and concentrate to remove free water, crystallize, and dry (about 180-200°C) to obtain 1170g of anhydrous calcium chloride.

Embodiment 3

[0049] Weigh 500% of waste residue (moisture content 38.0%) into a 1000ml beaker, slowly add 520g of 65% nitric acid, stir while adding, slowly release carbon dioxide gas (about 60 liters), after the dropwise addition, measure pH = 1.8. Suction filtration, drying to obtain 48g of black filter residue (the main component is carbon). The filtrate is heated to 70-100°C, the filtrate is adjusted to pH = 9.0 with an appropriate amount of calcium hydroxide, and then left to stand, filtered, evaporated and concentrated to remove free water, crystallized, and dried (about 180-200°C) to obtain 630g of calcium nitrate tetrahydrate.

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Abstract

The invention relates to a comprehensive utilization method of a cyanamide waste residue. The comprehensive utilization method of the cyanamide waste residue comprises the following steps: firstly, adding an acid into the cyanamide waste residue for reaction, collecting carbon dioxide gas generated in the reaction, and filtering a reacted solution to obtain a filter residue A and a filtrate A; heating the filtrate A to 30-100 DEG C; regulating pH to 7.0-9.0 by using lime milk; filtering again; and evaporating for concentrating, crystallizing and drying an obtained filtrate Bto obtain a calcium salt. Through effective treatment of the cyanamide waste residue, inorganic calcium salts (such as calcium chloride, calcium nitrate and calcium nitrite) or organic calcium salts (such as calcium formate, calcium acetate and amino calcium sulfonate), graphite powder and carbon dioxide can be prepared, thus achieving recycle of industrial wastes; the comprehensive utilization method is simple in whole technical process and low in treatment cost; and the added valve of the product is greatly improved.

Description

technical field [0001] The invention relates to the technical field of chemical production, in particular to a comprehensive utilization method of cyanamide waste residue. Background technique [0002] Lime nitrogen used industrially is produced by the following nitriding reaction, so it is unavoidable to mix carbon components in lime nitrogen. [0003] CaC 2 + N 2 → CaCN 2 + C [0004] The current technology is to disperse lime nitrogen into water or alcohol, such as U.S. Patent USP-pat5017355, after passing carbon dioxide gas into the solution, the insoluble part in the suspension formed is a mixture of calcium carbonate and carbon generated, which is filtered to obtain Aqueous solution of cyanamide. [0005] U.S. Patent USP-3300281 records a method in which lime nitrogen is added into water to form a suspension and reacts with carbon dioxide gas during the continuous production of cyanamide aqueous solution. [0006] After lime nitrogen is dispersed into wa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/20C01B31/04C01F11/28C01F11/38C07C51/41C07C53/10C01B32/205C01B32/215
CPCY02A50/20
Inventor 芮海平张文彦李鹏程
Owner 宁夏兴平精细化工股份有限公司
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