Abstract
The limoite which contains much arsenic has been roasted under several conditions. In the stream of air, it is necessary to heat above 1000°C to get good results, but if the graphite was added this temperature can be reduced to about 900°C. Addition of pyrite is effestive for the removal of arsenic, while that of pyrite cinder gives bad effect. Calcium carbonate also hinders the removal of arsenic.
In the streams of nitrogen and carbon dioxide, good results can be obtained at lower temperatures and in these cases too, graphite is effective and calcium carbonate is injurious for the removal of arsenic.
