Method for extracting ammonium thiocyanate from coking desulfurization waste liquid

A technology of coking desulfurization waste liquid and ammonium thiocyanate, which is applied in the fields of thiocyanate, chemical instruments and methods, water/sewage treatment, etc., can solve the problems of low purity of ammonium thiocyanate, poor economic benefits, and low price. Achieve the effects of easy promotion, easy operation, and uncomplicated technological process

Inactive Publication Date: 2011-07-20
陈琳
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The ammonium thiocyanate purity obtained by this method is relatively low, generally between 70% and 90%, and the purity is difficult to reach more than 95%.
The use of ammonium thiocyanate with lower purity is limited, the price is low, and the economic benefit is relatively poor

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Take 1,000 kg of desulfurization waste liquid from the coking plant of Hunan Valin Lianyuan Iron and Steel Co., Ltd., add 50 kg of activated carbon to the desulfurization waste liquid, heat to 70°C, keep stirring for 3 hours, and filter; add 60% volume fraction to the filtrate in a closed container 40 liters of sulfuric acid to the filtrate PH=3.5, heated to 60 ° C, kept stirring for 3 hours, the sulfur dioxide (SO 2 ) gas is drawn out with a catheter and absorbed with dilute ammonia water. Filter after the reaction is over, and detect that the amount of ammonium sulfate in the filtrate is 475.1 mol (mol), add 150 kg of barium hydroxide octahydrate, heat to 60 ° C in a closed container, keep stirring for 3 hours, and use a catheter for the released ammonia gas Extract it and absorb it with water; filter after the reaction, and the filtrate is heated, evaporated and crystallized to obtain the ammonium thiocyanate product, whose product quality reaches the industrial firs...

Embodiment 2

[0015] Take 1000 kg of desulfurization waste liquid from the coking plant of Hunan Valin Lianyuan Iron and Steel Co., Ltd., add 30 kg of activated carbon, heat to 90 ° C, keep stirring for 1 hour, and filter. Filtrate adds 30 liters of sulfuric acid of volume fraction 75% to filtrate PH=3.5 in airtight container, is heated to 80 ℃, keeps stirring 1 hour, the sulfur dioxide (SO 2 ) gas is drawn out with a catheter and absorbed with dilute ammonia water. Filter after the reaction is over, and detect that the amount of ammonium sulfate in the filtrate is 447.8 mol (mol), add 141 kg of barium hydroxide octahydrate, heat to 60 ° C in a closed container, keep stirring for 3 hours, and use a catheter for the released ammonia gas Draw out and absorb with water. After the reaction is completed, filter, and the filtrate is evaporated and crystallized to obtain ammonium thiocyanate product, and its product quality reaches the industrial first-class product standard of "Industrial Ammoni...

Embodiment 3

[0017] Take 1,000 kg of waste liquid from the coking plant of Hunan Valin Lianyuan Iron and Steel Co., Ltd., add 40 kg of activated carbon, heat to 80°C, keep stirring for 2 hours, and filter. Filtrate is added the sulfuric acid 35 liters of volume fraction 65% in airtight container to filtrate PH=4.5, is heated to 70 ℃, keeps stirring 2 hours, the sulfur dioxide (SO 2 ) gas is drawn out with a catheter and absorbed with dilute ammonia water. Filter after the reaction is over, and detect that the amount of ammonium sulfate in the filtrate is 465.2 mol (mol), add 145 kg of barium hydroxide octahydrate, heat to 80 ° C in a closed container, keep stirring for 1 hour, and use a catheter to release the ammonia gas that escapes. Draw out and absorb with water. After the reaction is completed, filter, and the filtrate is evaporated and crystallized to obtain ammonium thiocyanate product, and its product quality reaches the industrial first-class product standard of "Industrial Ammon...

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PUM

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Abstract

The invention discloses a method for extracting ammonium thiocyanate from coking desulfurization waste liquid. The method comprises: adding 3-5% of activated carbon to the coking desulfurization waste liquid, heating the mixture to 70-90 DEG C, stirring the mixture for 1-3 hours and filtering the mixture; adding sulfuric acid to the filtrate in a closed container to ensure the pH value of the filtrate to be 3.5-4.5, heating the mixture to 60-80 DEG C and stirring the mixture for 1-3 hours, leading out the escaping SO2 with a conduit and absorbing the escaping SO2 with dilute ammonia water; filtering the reaction liquid, adding barium hydroxide octahydrate with mass being equal to the mass of ammonium sulfate in the filtrate, heating the mixture to 60-80 DEG C in a closed container, stirring the mixture for 1-3 hours, leading out the escaping ammonia with a conduit and absorbing the escaping ammonia with water; and carrying out filtering after completing reaction, and heating, evaporating and crystallizing the filtrate to obtain the ammonium thiocyanate product with purity being more than 97%.

Description

technical field [0001] The invention belongs to the field of recovery and treatment of chemical wastewater, and in particular relates to a method for extracting ammonium thiocyanate from coking desulfurization waste liquid. Background technique [0002] At present, many domestic coking plants adopt the HPF desulfurization and decyanation process, which must discharge part of the desulfurization liquid and replenish water to maintain a high desulfurization efficiency. Coking desulfurization waste liquid contains a large amount of ammonium thiocyanate, which is a chemical product with high added value. Extracting ammonium thiocyanate from coking desulfurization waste liquid is a feasible method for resource treatment of desulfurization waste liquid. [0003] At present, the main method of extracting ammonium thiocyanate from coking desulfurization waste liquid in China is vacuum distillation and concentration, followed by fractional crystallization to obtain ammonium thiosulf...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01C3/20C02F1/58
Inventor 陈琳
Owner 陈琳
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