| The paragenetic mineral of mirabilite and bloedite are very abundance in our country,which occupy a pivotal position in the world’s total reserves, and have a good quality. Buttheir comprehensive utilizations are still technical challenge to solve. At present, manyresearchers have focused on the recycling of sodium without consideration of therecycling of magnesium and calcium salt, which could consequently cause huge waste ofresources of magnesium and calcium. In addition, the waste slag and sludge precipitationof calcium and magnesium can cause environmental pollution in the process. The purposeof this experiment is Provide the thermodynamic data of recycle magnesium and calciumsalt from paragenetic mineral of mirabilite and bloedite.In the experiment, magnesium sulfate and calcium chloride are partially separatedin the symbiotic resources by adding organic solvent ethanol, into water-salt systemsaccording to the salting to make magnesium chloride. So it will gain that more useful saltare separated out, and achieve efficient utilization of resources. This provided a novelmean for comprehesive utilization of paragenetic mineral of mirabilite and bloedite, andhas great significance on increasing utilization benefit of paragenetic mineral ofmirabilite and bloedite.In this theses, solubility, refractive index, conductivity, PH and salting out rate thephase diagrams were obtained via isothermal dissolution equilibrium method at30℃.when quaternary system MgCl2-MgSO4-CH3CH2OH-H2O and its boundary systemsMgCl2-CH3CH2OH-H2O and MgSO4-CH3CH2OH-H2O reach the equilibrium. Then,phase diagram is drawn. Solid phases were confirmed together by wet residue methodassisted by XRD.Experimental results show that: the ternary system MgCl2-CH3CH2OH-H2O,MgSO4-CH3CH2OH-H2O and CaCl2-CH3CH2OH-H2O, the refractive index of saturatedliquid phase will decrease with increasing the alcohol content in different alcohol-watervolume ratio at30℃and so does the conductivity. In addition, the alcohol-water systemof different volume ratio will have its corresponding solid phase, but the more content ofalcohol, the less content of crystal water of equilibrium solid. It explains that ethanol has dehydration.For the quaternary system of MgCl2-MgSO4-CH3CH2OH-H2O andCaCl2-MgCl2-CH3CH2OH-H2O, the system appear many different crystalline regions,which are the crystallization fields of magnesium sulfate and magnesium sulfate hydrated（calcium chloride and calcium chloride hydrated, magnesium chloride and magnesiumchloride hydrated, total saturated zone, all-solid-phase region, etc by changingethanol-water volume ratio.For MgCl2-MgSO4-CH3CH2OH-H2O, the unsaturated region becomes smaller whenincreasing alcohol’s content. While CaCl2-MgCl2-CH3CH2OH-H2O’s unsaturated regiondoesn`t change until the alcohol-water ratio is5:5. Therefore, the larger the ethanol-waterratio is, the more obvious of salting and the more salt to abstract.In addition, with increasing the ethanol-water volume ratio, hydrate brings lesscrystal water, which indicates that ethanol has dehydration. In summary, the bestproportion of magnesium salt and calcium salt can be gained when the ethanol-watervolume ratio of quaternary system is5:5. |
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