Optimization of arsenic behavior during concentrate roasting process

Abstract

Copper concentrates almost always contain certain quantity of arsenic, from 0.01-1%. Domestic concentrates processed in Bor Smelting Plant usually contain small quantity of arsenic (0.05-0.15%) except from Bor concentrate with 0.5-0.8%As. Arsenic and its compounds are toxic materials and they easy evaporate even at low temperatures. During pyrometallurgical processes arsenic and its compounds transfer into gas phase and cause environmental and operating pollution. This paper presents possibilities of arsenic transfer into form less harmful for environment and defining the optimal working parameters of roasting process. Investigations show that a behavior of arsenic in pyrometallurgical process is highly dependant from temperature, time, and roasting atmosphere. Laboratory investigations were conducted with Bor flotation concentrate with high arsenic concentration (2.73-3.29%) and they show that evaporation of arsenic increase with increase of temperature and time of roasting. Results of investigations show possibilities of arsenic distribution in smelting gases, i.e. decrease of arsenic content in gases emitted in atmosphere.