Research On Recycling Silicon Carbide Powder From The Cutting Waste Of Silicon Wafer

Silicon wafer is the basis material of semiconductor, solar energy and otherindustries. The waste from cutting silicon wafer contains of a lot of silicon carbideparticles, silicon powder and scrap iron. High economic value of silicon carbiderecycled from this waste can be reused in wafer cut, manufacture of semiconductors,ceramics, etc.Firstly, acid-base purification method is used to purify the waste, and the paperdiscess the effect of silicon carbide purity from pickling factors(concentration of acid,liquid-solid ratio, the reaction temperature, reaction time) and alkaline cleaningfactors(the type and concentration of alkali solution, liquid-solid ratio, reaction time,reaction temperature). The following conclusions from experiment: under picklingconditon:3.0mol/L of hydrochloric acid concentration,2.0:1mL/g of liquid-solidratio,60℃of reaction temperature,50min of reaction time. Under alkaline cleaningconditon:15%sodium hydroxide solution concentration,2.5:1mL/g of liquid-solidratio,50℃of reaction temperature，8min of reaction time. After purifying, thepurity of silicon carbide is up to99.44%. At the same time, the kinetics of leachingiron with muriatic acid from the waste are studied, and kinetic parameters areobtained. The results show that this reaction process is in accordance with unreactedshrinking core model influid-solid uncatalyzed reaction, the control step is fluidviscous flow control.Secondly, froth flotation purification method is used to purify the waste byusing kerosene as a collector through initial separation and last separation. The effectsof collector concentration, pH value of flotation solution, solid-liquid ratio andparticle size on the separation result are investigated. The obtained best separationresult shows that the purity of the silicon carbide powder in the float is up to99.08%under the50mL/g of collector concentration,8.3of pH value,3:400g/mL of solid-liquid ratio and8.636μm of particle size. At the same time, the paper discuss the theflotation mechanism, the infrared spectroscopic analysis of the material before and after flotation shows that the adsorption method of kerosene and silicon carbide isphysical absorption.