Process for extracting ammonium thiosulfate and ammonium thiocyanate from coke-oven gas desulfurization waste liquid

Abstract

The invention relates to a process for extracting ammonium thiosulfate and ammonium thiocyanate from coke-oven gas desulfurization waste liquid, which comprises the following steps of firstly, adsorbing the preliminarily filtered desulfurization waste liquid with activated carbon for deep decoloration treatment, carrying out negative pressure evaporation concentration on the decolorized waste liquid, and then carrying out crystallization separation purification to prepare ammonium thiosulfate and ammonium thiocyanate products. According to the process, fractional crystallization is adopted, the extracted salt does not need to be separated subsequently, the overall process is simple, the cost is low, no pollution is caused to the environment, sulfur in the desulfurization waste liquid is extracted more thoroughly, and the purity of the extracted salt is high and can reach 99% or above.

Description

Technical field[0001]The present invention relates to a coke oven gas desulfurization process, particularly a process of extracting ammonium sulfate and ammonium thiocyanate by coke oven gas demeal.Background technique[0002]The coke oven gas is a combustible gas generated by coking coal in a coke oven, which is a combustible gas in the coke industry. The coke industrial is suitable for use as fuel and urban gas, but contains a small amount of carbon monoxide and hydrogen sulfide. In order toxic substances, it is necessary to treat the desulfurization or the like before combustion, such as the sulfur dioxide, etc., which use the liquid to treat the coke oven gas to directly harm the environment, so it needs to be carried out in the liquid extract. The existing process is mostly a plurality of salt synchronous crystals from the desulfurization liquid, and the plurality of salts extracted together, and the extracted mixture also includes a small amount of separated filtration filtered....

AI Technical Summary

Problems solved by technology

Most of the existing processes for extracting salt from the desulfurization liquid adopt the method of synchronous crystallization of multiple salts. The various salts extracted by this method are mixed together, and the extracted mixture also includes a small amount of other salts filtered out by the separation and filtration operation. components, the subsequent separate separation of the target salt requires additional processing steps, which is time-consuming and labor-intensive, increasing the cost, and the purity of the salt extracted by the existing process is low. The lower the purity of the target salt, the more impurities in the finished product. Cause new pollution or new processing problems. In the prior art, because a small amount of ammonium thiosulfate and ammonium sulfate in the ammonium thiocyanate finished product are mixed salts, they are not up to the national standard and cannot be sold. They can only be sold separately by the manufacturer. Therefore, the higher the purity of ammonium thiocyanate, the more it can avoid a lot of cost waste caused by the subsequent treatment of the impurity components in the finished product of ammonium thiocyanate

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