Method for preparing sodium thiocyanate by using desulphurization waste liquid of coke oven gas

Abstract

The invention discloses a method for preparing sodium thiocyanate by using desulphurization waste liquid of coke oven gas, and belongs to the technical field of utilization of desulphurization waste liquid of the coke oven gas. The method comprises the following steps: using the desulphurization waste liquid of the coke oven gas as a raw material, firstly, filtering the waste liquid in vacuum, using tributyl phosphate to extract thiocyanate radicals in the waste liquid, then using sodium hydroxide solution to back-extract the extract, and finally concentrating and crystallizing the extract, and washing and drying the crystals to obtain sodium thiocyanate crystals. The method uses the desulphurization waste liquid of the coke oven gas to prepare a sodium thiocyanate product with the purityas high as 93 to 95 percent so as to change waste into valuable and makes full use of waste resources; and the method is simple, saves energy, has no three-waste discharge, is favorable for environmental protection, has low production cost and good economic benefit, and develops a new path for the utilization of the desulphurization waste liquid resources of the coke oven gas. The sodium thiocyanate product prepared by the method can be widely applied in the industries of medicaments, textile, printing and dyeing, pesticide, chemistry and the like.

Description

1. Technical field [0001] The invention belongs to the technical field of utilizing coke oven gas desulfurization waste liquid, in particular to a method for preparing sodium thiocyanate from coke oven gas desulfurization waste liquid by using tributyl phosphate (TBP) extractant. 2. Background technology [0002] Sodium thiocyanate (NaSCN) has a wide range of applications. It is used in the pharmaceutical industry for the separation of antibiotics; in the textile industry as a spinning solvent for polyacrylonitrile fibers; in the printing and dyeing industry as a dye dispersant, fabric dyeing agent, etc.; In the pesticide industry, it is used to manufacture fungicides, insecticides, herbicides, etc.; in the chemical industry, it is used as metal detectors such as silver and copper, and raw materials for the manufacture of thiourea. Therefore, the production and preparation of sodium thiocyanate has high economic value. [0003] During the coking process, about 30% to 35% of...

AI Technical Summary

Problems solved by technology

The main disadvantage of this method is: coke oven gas desulfurization waste liquid contains not only thiocyanate, but also anions such as thiosulfate, sulfate, and cyanide. When treated with D201 anion exchange resin, they will be enriched at the same time. , so the selectivity of this method is poor, and the ammonium thiocyanate (NH 4 SCN) contains a large amount of impurities, the purity is not high, and the product application is limited. The regeneration of D201 anion exchange resin will produce a large amount of waste liquid, which is difficult to handle and pollutes the environment.