Preparation Of Potassium Carbonate And Sulphate From Potassium Feldspar Of Lushi County

Potassium carbonate is an important inorganic chemical material. Electronicclass potassium carbonate (China National Standard GB/T 1587-2000 typeâ…¡) ismainly used in TV screen and optical glass industry. Potassium sulfate is the mostbroad potassium fertilizer without chloride in application, Potassium sulfate is mainlyused in glass industry, coloring matter, flavor industry. It is used for relaxed evacuantin the field of medication.With the rapid demand of potassium carbonate and potassium sulfate, in China, itis short in soluble potassium resources, consequently, it is the most important toexploit the vast reserved insoluble potassium ores in China.Based on the research work of our group, after synthesis of tobermorite frompotassium feldspar of Henan province Lushi County, synthetic tobermorite wasstudied for the condition of washing, we can clearly see that the all ratio ofdeliquescent K₂O came up to 85%, the maximum is 95.8%, after washing the filtercake of the synthetic tobermorite for 3-4 times. In the second place, the solution wasacidified by CO₂, pH is contained between 6.0 and 8.0. Here, the residue, a majorityof Si and Al, was removed by acidifying. The residue was removed by filtration up tothe content of the residue is acceptable. And then the solution was concentrated byvaporizing. When the density is up to 1.4441mg/L, the ethanol is put into the solutionto reduce the solubility of potassium bicarbonate. K₂CO₃ prepared by filtratedsolution is up to GB/T1587-2000â…¡ specification.In addition, potassium sulfate was prepared also, vitriol was put into the solutionwithout the residue, while the density is up to 1.1779mg/L through less vaporizing,and then joined the ethanol into the solution to reduce the solubility of potassiumsulfate in mixed solution. The bulk ratio of CH3CH2OH and H2O is 1:1, now thesolubility of potassium sulfate is 0.0705 g/100mL. The isolated ratio of K₂SO₄ ismore than 95.61%. The product of K₂SO₄ was desiccated 2 hours at a temperature of250℃,in conclusion, K₂SO₄ prepared by filtrated solution is up to GB specification.The KHCO₃-NaHO₃-H₂O system has been studied by evaporation-equilibriummethod at a temperature of 35℃±1℃. After crystal is isolating, The solid and theliquid phase have been analyzed for their properties, including the refractive index,the liquid density and conductance, pH, the content of K+& Na+, solid weight, XRD,etc. They show that the refractive index rises with the ratio of K+/Na+ and does notchange after reaching some point.