Study On Comprehensive Utilization Of Chromium Glauber’s Salt

With the development of economy, the demand of various sectors of chromiumsalts is increasing year by year, which has led to the chromium salt industry bringenvironmental pollution problems prominently, especially emissions of chromium slag,Chromium byproducts as a breakthrough was discussed, which help to solve thepollution problem and rational use of chromium glauber’s salt be turning waste intotreasure.In this paper, chromium glauber’s salt from a chromic salt factory in Chongqing asraw materials was discussed to presents a set of chrome glauber’s salt comprehensiveutilization scheme, namely removing the chromium from chrome glauber’s salt–glaub-er’s salt double decomposition system-mother liquor of ammonium sulfate puri-fication system. and the various stages of the main influence parameters were discussedin detail to get the conclusion as follows:In the process of removing the chromium from chrome glauber’s salt, combinedwith the actual production, three methods were set up, namely washing, recrystallizationand chemical precipitation. Through the comparison a reasonable except chrome pathwas determined, chemical precipitation method after washing, The washing processparameters as follows: washing times1, solid-liquid ratio5/4, good effect for85%canbe achieved; Chemical precipitation parameters as follows, glauber’s salt saturatedsolution in40℃, heat preservation mixing, and then with sulfuric acid to adjust pH to2, according to the rate of charge1:5sodium bisulfate was joined, reaction30min,sodium hydroxide solution to adjust pH to approximately7, centrifugal separation, getsaturated solution of glauber’s salt without chrome. The rate above99%.In the process of double decomposition system for soda ash, the best reactioncondition was explored: saturation glauber’s salt solution （40℃）, in the mixing state,was added ammonium bicarbonate according the reactant ratio1:1.2, charging1h, thenreaction1.5h, the suction filter, eluting separation, drying,test sampling quantity,product yield at about60%, the purity can reach more than98%.In the process of the mother liquor purification system for ammonium sulfate, thethree methods were explored, respectively evaporation-cooling–evaporation,refrigeration-evaporation and solution crystallization. Through the three methodscontrast the reasonable path was determined finally. The pH of mother liquor was transferred to4by sulfuric acid, after the first100℃evaporation, evaporation is V1/V for9/20, at this time Na2SO4content is about32%, after the separation of crystalmother liquor in room temperature （25℃） natural crystal, centrifugal separation,cooling mother liquor again100℃evaporation, evaporation is V3/V2for7/10, stopevaporation, drying, namely get by-products （NH₄）₂SO₄, the determination of thecontent of N can reach20.8%, in line with ammonium sulfate present national standardGB535-1995requirement.