The Research On The Preparation Of Al-Si Alloy Using Waste Silicon Powder

With the development of science and technology,the energy shortage is increasing day by day.Among the renewable energy sources currently being developed,photovoltaic power generation is growing at the fastest pace,and China holds more than 90%of the global market share of photovoltaic cells.In the same rapid development of the semiconductor industry,in the context of the rapid growth of the global semiconductor industry,mainland China has the highest growth rate of semiconductor production capacity.The rapid development of these industries has brought about a surge in the production of silicon products,and the diamond wire saw-cutting process,which is widely used in silicon wafer cutting,generates 30%to 50%of waste during processing.As the production capacity of silicon products grows,so does the amount of silicon scrap generated.The original treatment method for silicon scrap can no longer meet the current treatment needs,and a new direction needs to be explored.In this paper,we propose a process solution for the preparation of aluminum-silicon alloy using a diamond wire saw to cut the scrap silicon powder.Firstly,the characteristics of the scrap silicon powder were initially explored,and it was found that its silicon purity could reach 97.0%,impurities were mainly Si O₂,and particles were all micron-level thin flaky fine particles,which could easily agglomerate in different shapes and sizes.On this basis,it was cold pressed into block blanks,and it was obtained by the orthogonal experimental investigation that the blanks with optimal drop strength could be obtained by mixing every 200 g of spent silica powder with40 g of yellow dextrin,20 ml of silica sol and 120 ml of water and pressing them for 45 s at 0.6MPa.The billets obtained in this way were melted with eutectic composition aluminum-silicon alloys,and the silicon yield was examined using the acid leaching method.The effect of silicon melting temperature,melting time,and pouring temperature on the silicon yield was investigated using orthogonal experiments.The factors affecting the silicon yield were,in descending order,the dissolution temperature,the dissolution time,and the pouring temperature.The best effect of silicon dissolution was achieved when the dissolution temperature was 950°C,the dissolution time was 30 min,and the pouring temperature was 720°C.The silicon yield was98.2%,and the silicon was mainly in the form of eutectic and uniformly distributed in the aluminum matrix.The results show that the silicon yield decreases when the dissolution temperature is too high or too low;the silicon yield increases with the increase of the dissolution time and reaches the peak at 30 min,and then remains unchanged;the pouring temperature has little effect on the silicon yield,and the highest yield is obtained at 720°C,and it decreases when it is higher or lower.This paper also investigates the influence of the silicon addition method,refining agent,slagging agent,and binder on the silicon yield.The experimental results show that:the silicon addition method has a great influence on the silicon yield,and the highest yield can be obtained by cold pressing into a block before melting.The amount of refining agent has little effect on the effect of silicon melting,but due to the use of yellow dextrin will be decomposed into gas and combustible materials when exposed to heat,insufficient refining agent will increase the number of pores and other defects in the alloy.Slagging agent has less effect on the silicon dissolution,when used in excess will cause a small amount of silicon precipitation,but the yield is still more than 95%.The increase in yellow dextrin binder will lead to a significant decrease in the yield of silicon,and its thermal decomposition of the adverse effects of the increase in the dosage has also significantly increased.