Study On The Influence Of High Flash Point Diluent On Rare Earth Extraction

In recent years,Environmental controls on volatile organic compounds?VOCs?emissions have become increasingly stringent,and rare earth enterprises have become the focus of environmental improvement.This paper aims to reduce the emission of VOCs exhaust gas from the source through the study of the synthetic solvent oil of a new kind of diluent,which is a major emitter of VOCs.Furthermore,the new kind of diluent could improve the operating environment of extraction line,which comply with the principles of clean production and green production,and improve the safety level of production plant,reduce the occurrence of fire safety risks.By measuring the physical properties of sulfonated kerosene,light white oil and synthetic solvent oil,this paper compared the similarities and differences of basic properties in four aspects.Firstly,under the same conditions,the densities of organic phase P₅₀₇07 prepared by synthetic solvent oil and synthetic solvent oil were both lower than that of light white oil and sulfonated kerosene,and the density of diluent decreased with the increase of temperature.Secondly,the kinematic viscosity?40??of synthetic solvent oil was 1.94 mm²/s,which was higher than that of light white oil and sulfonated kerosene.Resulting in less fluidity than light white oil and sulfonated kerosene.Thirdly,the flash points of sulfonated kerosene,light white oil and synthetic solvent oil were 40⁶0?,70⁸5?and 102?respectively.Meanwhile,the flash point of sulfonated kerosene and light white oil prepared as P₅₀₇07 organic phase increased,while the synthetic solvent oil decreased,but higher than sulfonated kerosene and lower than light white oil.Fourthly,when volatilized at 60?for 20h,the volatilization rate of sulfatated kerosene,light white oil and synthetic solvent oil were 10.38²8.08%,5.5⁸.11%and 1.64%respectively.From the above results,the volatilization rate of synthetic solvent oil was the lowest one,with a small increase as the temperature increased,which could significantly reduce VOCs emissions.According to the measure of separation coefficient,Ce/La separation ability of organic phase prepared by synthetic solvent oil was not as good as that of light white oil and sulfonated kerosene,Sm/Nd separation ability and Nd/Pr separation ability were similar to that of light white oil,and Pr/Ce separation ability was slightly better than that of light white oil.From cerium praseodymium separation and extraction test,neodymium samarium separation and extraction test,it could be seen that the load capacity,separation ability of P₅₀₇07 organic phase,which was synthesed by synthetic solvent oil were not significantly different from that of light white oil and sulfonated kerosene.Furthermore,there was no emulsification in the extraction process,and occasionally a small amount of oil was entrapped in water during washing.That the substitution of synthetic solvent oil will not weaken the organic phase and can be used in industrial applications.To produce one ton of rare earth oxide required RMB 369.51 sulsulated kerosene,which could save RMB 92 yuan by replacing with light white oil,and RMB 149 yuan by synthetic solvent oil.Based on the annual output of a rare earth enterprise in the north of China of 27,000tons of oxide,replacing synthetic solvent oil GV-18A could save RMB 4.023 million yuan in raw materials and auxiliary materials,saving 40.3%of the cost,with considerable benefits.