多晶硅水性切削液除硅研究

Remove silicon from water-based polycrystalline silicon cutting fluid

以废切削液回收PEG后剩余的废砂为原料，采用酸溶和碱溶两种方法除去废砂中的多晶硅杂质，回收SiC微粉，并对两种方法的可行性及工艺条件进行了研究。结果表明，酸法除硅时，当HF浓度为4mol／L，硝酸浓度为2mol／L，温度为35℃，反应时间为70min时，可使回收微粉中硅杂质含量在0．1％-0．2％。碱法除硅时，当NaOH的溶液3％左右，温度在70℃，反应时间2h，可使回收微粉中硅杂质含量在0．2％～0．3％。粒度分析表明，酸法及碱法回收产品粒径分布均能满足指标要求，且碱法回收产品粒径分布与新砂一致。

After the PEG had been recycled from cutting fluid, the remaining waste materials were used as raw materials for this study. Both acid and alkali methods of dissolve silicon were used to recycle silicon carbide powders. Also the feasibility and conditions of two methods were studied. The results showed that when the HF concentration is 4 mol/L,nitric acid concentration is 2 mol/L,temperature is 35℃,reaction time is 70 min,the recycling content of silicon powder can reach as low as 0.1% -0.2% ;and for the alkali method, when NaOH solution concentration is 3 %, the temperature is 70℃, reaction time is 2 h, the recycling content of silicon powder can reach as low as 0.2% -0.3%. Recycled powder products got by two methods had been analyzed by size distribution, and both of them can meet the requirements. The product got from alkali method is familiar with new SiC sand in size distribution.