Technological Study Of Resource Utilization Of High-salt Wastewater By Soda And Ammonium Chloride Manufacture Process

In many field of industrial production process such as petrochemical industry,coal chemical industry,pharmacy,metallurgy and so on,will produce a huge amount of wastewater,including a class of wastewater which dissolve much inorganic salt,the inorganic salt dissolved in this kind of high salt wastewater is mainly sodium sulfate and sodium chloride.Such direct wastewater emissions without treatment,not only waste mineral resources,but also can destroy the surrounding soil and result in higher water salinity,at the same time this also have a serious impact to the agricultural and industrial production.Under the current situation of the relative lack of water resources,,looking for a kind of industrial wastewater emissions reduction and make the maximize use of salt resources process,not only can alleviate the shortage of water resources,but also can reduce pollution to the environment,this has the dual strategic significance to economy and environment.In this paper,we make the high salt wastewater contains high concentrations of sodium sulfate and sodium chloride recycled use on the basis of in-house alkali process method,this paper proposes a no emissions,environmental protection and high salt wastewater treatment process.This method make the high salt waste water enrichment at first,so that the sodium chloride and sodium sulfate in aqueous solution reach saturation state at the same time.Under a certain temperature add a certain amount of solid ammonium bicarbonate to the wastewater,let the sodium salt in the waste water reaction to the sodium hydrogen carbonate precipitation,then solid-liquid separation after a certain period of time reaction,then wash the suction filter,then roast the sodium bicarbonate we can get soda ash,we evaporate a certain water and cool the filtrate to fixed temperature,then suction filtration,separate the mixed cooling crystallization of the ammonium salt.Isolate we get mixing ammonium salt crystallization.After separation crystallization mix the mother liquor with new quantitative high salt waste water until reach the initial processing volume and then continue a new round of cycle.In order to achieve high purity of product sodium bicarbonate and by-product ammonium salt and high cycle efficiency,in this experiment we compare and research on the reaction time,reaction temperature,concentration of water evaporation and end cooling temperature in the process of on wastewater treatment.The research shows that when the sodium chloride and sodium sulfate in initial high salt wastewater are in saturated state,every time when the capacity is 1 L,when reaction time is 90 min,reaction temperature set to 35?,the evaporation of water quality is 350 g,end cooling temperature is 25 ?,the effection of the treatment is good.Under the selected process condition we treated the wastewater for 40 times,and we determined the composition of the ammonium salt mixture and mother liquor and finally verify the stability and convergence of the process.After treating the high salt wastewater we detected the purity of ammonium salt and soda ash,the results show that in utilization of sodium has realized the single cycle for 94.5%of the cases the byproduct ammonium salt mixture and product soda ash have a high purity,The soda ash can reach the national standard GB210.I qualification standards in 2004.The mixing ammonium salt can be used as agricultural fertiliser.In this research we also studied the process dynamics of first step reaction which generates sodium hydrogen carbonate precipitation,discussed the dynamics factors of alkali reaction system by inspecting the sodium alkali production reaction rate under the condition of different temperature and different initial concentration,the result indicated the reaction is a first order reaction,its dynamic model is:-ln(1-X)= 0.09322 × CA00.6573 exp(-6.8175 × 103/RT)t + 0.259 This method has the advantage that the cost of raw material is low,the process is simple,less investment.Its economic benefit is good,no emissions of waste liquid and waste residue,no pollution,all salt in wastewater can be converted into useful ingredients,achieving the goal of maximum resources recycling.This provides a feasible technology way for zero discharge waste water.