Research On Preparation HighQuality Silicon With Carbonized Rice Husk And PetroleumcokeMixed Reductant

Petroleum,natural gas and coal aregenerally referred to asconventional fossil fuels,and reserve of fossil fuel energy sources will be depleted in afew decades.In addition,over-reliance onfossil fuels will have disastrous consequences because excessiveamounts of carbondioxide emission have dramatic global warming effects.Therefore use ofgreen and renewable energy sources is much more important in the future world.Solar energy is one of the most widely adopted renewableenergy source.The world,especially the United States,Japan,Germany and other developed countries have launched a large-scale national PV development plan to stimulate the rapid development of photovoltaic industry.The main obstacle of the photovoltaic industry application process is the high costs and a shortage of silicon materials.At present,the polysilicon production are improved Siemens method for preparing the polysilicon,the core technology of polysilicon is mainly dependent on expensive imports,and metallurgy method of solar-grade polysilicon has low cost and environmentally friendly features,so metallurgical Preparation of solar-grade polysilicon to China's own intellectual property rights and the development of China's photovoltaic industry is of great significance.This paper is the use of carbonized rice husk,petroleum coke mixed reductant and high purity quartz sand preparation of high quality silicon,lay a foundation for the next step of purification for solar energy polysilicon.In this paper,the main research contents and research results are as follows:(1)Purification treatment:application of ultrasonic acid leaching technology,purifying the carbonized rice husk,determines the investigation within the scope of the optimization of process parameters:carbonized rice husk size of 100-120 mesh,solid-liquid ratio of 1:10,hydrochloric acid concentration of 14 wt%,water bath temperature of 40 ℃,ultrasonic frequency of 45kHz,ultrasonic power of 300 w,leaching time of 120 min,iron removal rate can reach 91.62%,the phosphorus removal rate can reach 84.25%,for subsequent smelting high quality silicon to quality raw materials.(2)Pickling iron removal dynamics research:Iron acid leaching process can be d escribed by shrinking nucleus model,conventional acid leaching reaction process belon gs to the hybrid control,Ea = 90.04 kJ/mol,and the reaction of hydrochloric acid ser ies was 1.63,the macroscopic reaction kinetics equation of expression:(1/3)ln(1-x)+[(1-x)-1/3-1]=8.65×1011C1.63d-0.27e(-90040/RT)t;Belong to hybrid control ultrasonic acid leaching reaction process,the reaction of hydrochloric acid with class,Ea = 89.87 kJ/mol,a-n d the reaction of hydrochloric acid series was 1.47,the macroscopic reaction kinetics equation expressions:(1/3)ln(1-x)+[(1-x)-1/3-1]=3.01×1012C1.47d-0.33e(-89870/RT)t.(3)Pellets preparation and physical properties of raw pellets research:using carbonized rice husk,petroleum coke,high purity quartz sand as raw material pressed pellets,respectively investigates the reductant proportioning,briquetting pressure and the amount of binder opposite pellets compressive strength and the influence of the porosity,determines the investigation within the scope of the group conditions as follows:in the mixed reductant carbonized rice husk and the quality of petroleum coke ratio of 1:3,binder addition amount of 4%,briquetting pressure of 35 MPa,on this condition of raw pellets air-dried,porosity rate was 29.5%,the compressive strength of 12.89 MPa.(4)Electric prepared high quality silicon research:the experimental results show that using the purified carbonized rice husk,petroleum coke mixed reductant and high purity quartz sand as raw materials melting silicon is feasible,and get the high quality silicon.Silicon purity is 99.67%,which the iron content is 0.198%,phosphorus is 0.086%,below the existing industrial silicon,iron,phosphorus and boron content has paved the way for the preparation of solar grade silicon.