Reuse Of Sulphur In Desulfurization Waste Liquid From Coal Coking And Synthesis Of Zinc Sulfide

Wet ammonia desulfurization method is used in most coal coking enterprises.In the desulfurization process,the treated industrial ammonia water(8%-18%)is used to absorb H2S or other sulfides from waste gas to achieve sulfur removal.However,this desulfurization process will produce a large number of desulfurization waste liquids,which are difficult to deal with and endanger the environment for human survival.There are mainly(NH4)2S2O3,NH4SCN and sulfur in the waste liquor of desulfurization because the main components of gas are H2S and HCN,which inevitably react with industrial ammonia water of alkali source to produce(NH4)2S and NH4SCN,and then oxidize to produce(NH4)2S2O3 or(NH4)2SO4 directly.When the concentration of these by-salts reaches a certain level,not only the desulfurizationL efficiency is greatly reduced,but also the pipeline is blocked.Domestic coal coking enterprises usually extract(NH4)2S2O3,NH4SCN or(NH4)2SO4 as by-salt by installing salt extraction equipment,aiming at reducing the total sulfur concentration in desulfurization waste liquor to ensure the efficient desulfurization of waste gas.As far as Xinjiang is concerned,some coal coking enterprises do not even have salt extraction equipment.They can only discharge part of the waste liquid every day and add the same amount of new alkali sources to continue desulfurization.A large amount of desulfurization waste liquid discharged is stored in ponds or fillings.Over the years,timely treatment of desulfurization waste liquid has become an urgent problem for these coal coking enterprises.Of course,this will not only affect the sulfur removal efficiency and economic benefits of coking enterprises,but also cause secondary pollution to the environment.At present,under the requirement of national environmental protection policy,Xinjiang coal-coke chemical enterprises must solve the problems of difficult to deal with a large number of desulfurization waste liquid,waste residue and wastewater recycling,so as to ensure that desulfurization efficiency will not be affected,and efficient and sustainable production.On the premise of minimizing secondary environmental pollution as much as possible,if the sulfur in desulfurization waste liquid can be extracted quickly and effectively.the sulfur with low added value can also be converted into by-products with high added value,which provides a train of thought for sustainable desulfurization of coal coking enterprises.This paper has carried out research on the above issues,the main findings are as follows:(1)Sulfur in desulfurization waste liquor was successfully converted into zinc sulfide materialby hydrothermal reaction.The utilization efficiency of sulfur can reach 40%,which realizes the reuse of sulfur in traditional ammonia desulfurization waste liquid.(2)The ammonia desulfurization process was improved from the sulfur existing form in desulfurization waste liquor(S2O32-to S2’),and the sulfur conversion efficiency was up to 91.5%.This not only shortens the reaction time,reduces the reaction conditions,production costs and equipment requirements,but also realizes the concept of environmental desulfurization and wastewater recycling.(3)A new ammonia desulfurization process was used to synthesize large quantities of white zinc sulfide materials by wet chemical reaction.The zinc sulfide powders were characterized by XRD,SEM,EDS and FTIR.The results showed that the synthesized zinc sulfide powders had high purity,uniform particle size and were not oxidized.This will greatly increase the added value of by-products of coal coking enterprises and may bring economic benefits to enterprises.