Researchon The Resource Utilization Technolog Of Electrolytic Manganese Composite Salt

Electrolytic manganese complex salt is a kind of neutral crystal produced during the production of manganese metal by electrolytic method.It is mainly composed of magnesium sulfate,ammonium sulfate,a small amount of manganese sulfate and trace other elements.Separating the main components and converting them into the same series of products with higher market value is an effective way to solve enterprise production and environmental pollution.Based on the difference in the solubility products of manganese carbonate and magnesium carbonate,this project uses liquid precipitation to separate manganese sulfate from magnesium sulfate.Firstly,use ammonium bicarbonate as a precipitant for preliminary manganese removal,and then use the oxidation method to completely remove manganese.The main components in the solution after the manganese removal are magnesium sulfate and manganese sulfate,and then use ammonium bicarbonate as a precipitant again.Basic magnesium carbonate product is obtained,and finally calcined to obtain magnesium oxide product.Through this process,the resource utilization of the electrolytic manganese composite salt is realized.Through experimental research,it was found that when n[NH4HCO3]:n[Mn2+]=2:1,pH value 7,reaction temperature 50?,reaction time 20 min,and aging time 40 min,the mass fraction of manganese carbonate in the precipitate can be as high as 88.7%,and the content of manganese ions in the filtrate can be reduced to 62 ppm at this time.After preliminary carbonization to remove manganese,it can be found that the content of manganese ions in the filtrate is still high,so it is necessary to perform deep manganese removal.After comparing the removal effects of some oxidants and manganese removal agents,it was found that the addition of ammonium persulfate can significantly reduce the residual manganese ions in the filtrate.At this time,the content of manganese ions in the filtrate was as low as 11.9 ppm.On this basis,a certain amount of the heavy metal trapping agent(TMT-15)and a small amount of flocculant polyacrylamide were stirred,allowed to stand,and filtered.Finally,the filtrate was found to have a manganese ion content as low as 2.4 ppm.At this time,it can be considered that the manganese ion has been completely removed.After the separation of manganese and magnesium,the solution was prepared by basic precipitation using chemical precipitation method.The best process parameters were obtained through single-factor experiments:pH10,carbon-magnesium ratio 2:1,reaction temperature 55?,reaction time 20 min,and aging temperature 90?.At this time,the yield of magnesium ions reached a maximum of 92.4%;the molecular formula of the obtained basic magnesium carbonate was 4MgCO3.Mg(OH)2.4H2O,in which the content of magnesium oxide was 42.2345%,the content of calcium oxide was 0.0228%,and the content of manganese was 7.962×10-4%,and the iron content is 4.573 ×10-3%.By XRD and SEM characterization of the product,it can be seen that the obtained basic magnesium carbonate has a layered structure and a relatively complete crystal form.During the calcination process,As the calcination temperature increases,the magnesium oxide gradually changed from the original lamellar structure into spherical particles,and finally calcined into a complete spherical structure at 950?.The surface adsorption force gradually decreased,and the activity decreased accordingly.The purity of magnesium oxide reaches the maximum.The purity of the magnesium oxide product calcined at this temperature is 99.9830%,the calcium oxide content is 0.0154%,the manganese content is 2.2319×10-4%,the iron content is 4.3548×10-3%,and the citric acid activity value is 150 s.Through this process route,not only the green treatment of electrolytic manganese composite salt is realized,the contradiction between production and environmental pollution is alleviated,but the comprehensive use of the preparation to obtain high value-added products increases the economic benefits of the enterprise,and has very Good market application prospects.