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Method for extracting sodium thiocyanate from coking desulfurization waste liquid

A kind of technology of coking desulfurization waste liquid and sodium thiocyanate

Inactive Publication Date: 2011-11-30
ANHUI UNIVERSITY OF TECHNOLOGY
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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 70-90%, 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

example 1

[0007] Take the coking desulfurization waste liquid provided by Tongling Xinyaxing Coking Co., Ltd. After analysis, the main components of the waste liquid are: NH 4 SCN 183g / L, (NH 4 ) 2 S 2 o 3 155g / L, (NH 4 ) 2 SO 4 47g / L, take 1 liter of the waste liquid, add 60g of activated carbon in a beaker, heat to 70°C and keep stirring for 1 hour, filter; add 60mL of 98% concentrated sulfuric acid to the filtrate in a closed container to pH = 3.5, heat to 80°C and Keep stirring for 1 hour, the evolved SO 2 The gas is drawn out with a catheter and absorbed with dilute ammonia water; after the reaction is completed, filter, and add NaOH96g and Ca(OH) to the filtrate in a closed container 2 110g, heated to 70°C and kept stirring for 1 hour, the escaping ammonia gas was drawn out with a catheter and absorbed into dilute ammonia water; after the reaction was completed, it was filtered, and the filtrate was evaporated and crystallized to obtain 178g of sodium thiocyanate product...

example 2

[0009] Take the coking desulfurization waste liquid provided by Huahao Coking Co., Ltd. in Changyi City, Shandong Province. After analysis, the main components of the waste liquid are: NH 4 SCN 136g / L, (NH 4 ) 2 S 2 o 3 107g / L, (NH 4 ) 2 SO 4 31g / L, take 1 liter of the waste liquid, add 20g of activated carbon to a beaker, heat to 90°C and keep stirring for 2 hours, filter; add 55mL of 70% concentrated sulfuric acid to the filtrate in a closed container to pH = 4.5, heat to 60°C and keep After stirring for 2 hours, the evolved SO 2 The gas is drawn out with a catheter and absorbed with dilute ammonia water; after the reaction is completed, filter, and add NaOH 72g and Ca(OH) to the filtrate in a closed container 2 75g, heated to 50°C and kept stirring for 1 hour, the escaping ammonia gas was drawn out with a catheter and absorbed into dilute ammonia water; after the reaction was completed, it was filtered, and the filtrate was evaporated and crystallized to obtain 12...

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PUM

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Abstract

The invention relates to a method for extracting sodium thiocyanate from desulfurization waste liquid in a coking plant, which is characterized by comprising the following steps of: adding 2 to 6 weight percent of activated carbon into the desulfurization waste liquid, heating to the temperature of between 70 and 90 DEG C, and keeping stirring for 1 to 2 hours; filtering, adding sulfuric acid into filtrate in a closed container until pH is 3.5 to 4.5, heating to the temperature of between 60 and 80 DEG C, and keeping stirring for 1 to 2 hours; leading escaping sulfur dioxide gas out by using a guide pipe and absorbing by using dilute ammonia water; filtering after reaction is finished, adding sodium hydroxide with the same mol as ammonium thiocyanate in filtrate and calcium hydroxide with the same mol as ammonium sulfate in the filtrate into the filtrate in the closed container, heating to the temperature of between 50 and 70 DEG C, and keeping stirring for 1 to 2 hours; and leading escaping ammonia gas out by using the guide pipe and absorbing by using water to obtain the dilute ammonia water, filtering after reaction is finished, and performing evaporation crystallization on filtrate to obtain a sodium thiocyanate product.

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 sodium 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 waste 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 th...

Claims

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Application Information

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IPC IPC(8): C01C3/20
Inventor 朱伟长
Owner ANHUI UNIVERSITY OF TECHNOLOGY
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