| Popis: |
Tungsten-copper(W-Cu) alloy is employed for manufacturing heavy duty contactors, relays,switches etc. During production of such components, W-Cu turnings/borings aregenerated. At CSIR-NML, a process for recovering tungsten and copper fromtungsten-copper borings containing 46.01% W, 53.78% Cu, 0.13% Fe and otherminor metals as high purity tungsten powder and copper powder has beendeveloped. In the present work, a detailed investigation on reduction ofammonium paratungstate (APT) having purity 99.95% by hydrogen gas to produce highpurity tungsten powder is presented. The various process parameters such astemperature, time and flow rate of hydrogen gas have been optimized. At the temperatureof 800°C and 0.1 lpm flow rate a reduction of 77.78% was observed upto 2h time. At 900°C, with increase in flow rate from 0.1 lpm to 0.3lpm the increase in reduction was found to be from 63.88% to 99.99% at 1h time.At still high temperature of 1000°C, almost complete reduction was obtainedat 0.1 lpm flow rate in 1h time. The effect of bed-depth was also carried out. Atall temperatures chemical reaction was the rate determining step. |
