Filtration of waste coolant from fixed-abrasive wire sawing and recycle of retrieved silicon powder for feedstock

For the purpose of this work, several types of waste coolants from fixed-abrasive wire sawing (FAS) were filtrated, and the characteristics of the coolants and the retrieved solid materials were investigated. The all coolants consisted of water and glycol series with the boiling temperature of around 200°C. However, the viscosity of each coolant were different due to the difference in the ratio of coolant components. Experimental results of pressurized filtration can be explained by a rate equation which we proposed. The concentration of diamond in the retrieved solid materials was less than 0.2wt%. Metal contents in the retrieved Si were measured by an inductively coupled plasma mass spectrometry (ICP-MS). The result indicated that quality of the retrieved Si is sufficient for the use as feedstock. The shaped Si was easily melted in a resistance heating furnace. We concluded that the Si powders in waste coolants from FAS can be used as feedstock.