Resource process method for coking sulfur-containing waste water

Abstract

The invention relates to a method for resourceful treatment of coking sulfur-containing wastewater. The coking sulfur-containing wastewater is added into a microfiltration or ultrafiltration membrane separator, solid elemental sulfur contained in the wastewater is entrapped and condensed, and is subject to the washing purification to produce pure sulfur; penetrating fluid is led into a nanofiltration membrane separator, ammonium thiosulfate is entrapped and condensed, and is extracted to produce the ammonium thiosulfate; then the penetrating fluid is led into a reverse osmosis membrane separator, ammonium thiocyanate is trapped and condensed, and is extracted to produce the ammonium thiocyanate, wherein, the penetrating fluid is purified water and can be returned to the working section for repeated use. The method can separate and purify valuable sulfur and secondary salt in the coking sulfur-containing wastewater to create certain economic value, can also improve the circulating utilization rate of industrial water to realize zero draining of wastewater and achieve the requirement of cyclic economy, and is suitable for treating the coking sulfur-containing wastewater of desulfurization and decyanization processes using a HPF method of various coking gas.

Description

technical field [0001] The present invention relates to a resource treatment method of coking sulfur-containing wastewater by membrane method, in particular to the separation and recovery of elemental sulfur, the purification of two salts of ammonium thiosulfate and ammonium thiocyanate from coke oven gas HPF desulfurization and decyanation process wastewater, and Implement the method of recycling purified water. Background technique [0002] The coking plant is an important part of the iron and steel enterprises. It mainly produces metallurgical coke for blast furnace ironmaking, and also recovers ammonia, benzene and other chemical products from coke oven gas. Its water supply and drainage is an important link to ensure production, but the discharged wastewater contains a large amount of organic and inorganic substances. Due to the influence of various factors such as the nature of raw coal, coking temperature, coking product recovery process, etc., its composition is com...

AI Technical Summary

Problems solved by technology

Patent CN101012065A provides a method for separating and recovering three kinds of ammonium salts from coke oven gas desulfurization and decyanation wastewater, but the method is cumbersome to operate, the separation efficiency is not high, and the yields of ammonium thiocyanate and ammonium thiosulfate are not high less than 50%, the resource recovery efficiency is low, and the treatment of elemental sulfur solids in coking sulfur-containing wastewater is not considered

It is worth mentioning that the treatment method of sulfur-containing wastewater provided by the patent CN1955120 uses membrane separation technology to successfully separate elemental sulfur and secondary salts. The requirements for conveying equipment and pipelines are relatively high. The latter consumes a lot of energy and is prone to generate sulfur foam to cause tower blockage, making continuous operation difficult; the salts ammonium thiocyanate and ammonium thiosulfate in the saline clear liquid are directly Evaporation and crystallization, the salt purity is not high

[0006] Regarding the literature on the separation of crystalline ammonium thiosulfate and ammonium thiocyanate, Zhang Mingyu and others used activated carbon to evaporate and decolorize, concentrate under reduced pressure, heat filter, and cool to crystallize to separate ammonium thiocyanate. This method needs to be clarified to remove insoluble matter first. The removal of insoluble matter takes a long time and the effect is poor; the clarified liquid needs to be heated to 100°C for evaporation and decolorization for 1 hour, which consumes a lot of energy; the separation of crystallization and mother liquor adopts vacuum filtration, the content of mother liquor in the crystallization is high, the product quality is poor, and the loss of salt in the decolorization process is large , there are many factors affecting the purity of ammonium thiocyanate, and the yield is not high, less than 60%. 59%, they all only crystallized and extracted ammonium thiocyanate, and did not study the recovery process of ammonium thiosulfate

Images