Recycling photovoltaic silicon waste for fabricating porous mullite ceramics by low-temperature reaction sintering

In this study, porous mullite ceramics with coral-like structures were fabricated at a low temperature of 900 degrees C by using photovoltaic silicon waste (PSW) as the silicon source directly. The effects of additive content and sintering temperature on the mullitization reaction of green bodies were studied. The results showed that ammonium molybdate tetrahydrate molybdenum (H24Mo7N6O24 center dot 4H(2)O) as an additive could reduce the reaction temperature for mullitization from 1100 degrees C to 900 degrees C. The research on the influence of catalyst on material properties showed that porous mullite ceramics with a flexural strength of 52.83 MPa, a 41.78 % porosity, a sintering expansion rate of 0.49 % and an average pore size of 0.23 mu m could be fabricated by introducing 7.5 % H24Mo7N6O24 center dot 4H(2)O at the sintering temperature of 1000 degrees C. This study develops an environment-friendly recycling method of PSW and provides a new idea for the low-cost preparation of porous mullite ceramics with high purity.

Automated summary

By studying the effects of additive content and sintering temperature on the mullitization reaction of mullite ceramics, it was found that ammonium molybdate tetrahydrate molybdenum can reduce the reaction temperature and potentially be used in the preparation of porous mullite ceramics. The research provides a new idea for the low-cost preparation of porous mullite ceramics with high purity using photovoltaic silicon waste.