Process and plant for treating ore concentrate particles containing valuable metal

摘要

A process and a plant for treating ore concentrate particles containing valuable metal and having at least arsenic and sulfur containing components. The process comprises a two-stage roasting process comprising a first roasting step and a second roasting step. A gas mixture is formed from the first process gas component obtained from the first roasting step and from the second process gas component obtained from the second roasting step. Post combustion of the gas mixture is made in a post combustion chamber that uses the sulphide rich first process gas component and the second process gas component as oxidizer gas in order to decompose SO3 in the gas mixture. The exit gas is exposed to subsequent gas cooling and dust removal steps.

主权项

1. A process for treating ore concentrate particles containing valuable metal and having at least arsenic and sulfur containing components, which process comprises:
roasting the concentrate particles in a first roasting step that creates first off-gas and operates with a low oxygen potential for dearsenifying the concentrate, treating the first off-gas leaving the first roasting step to separate calcine and a sulfide-rich first process gas component, roasting the calcine led from the first roasting step in a second roasting step that creates second off-gas and operates with an excess of oxygen, and treating the second off-gas leaving the second roasting step to separate calcine and a second process gas component, wherein the process further comprises forming a gas mixture of the first process gas component and the second process gas component, the gas mixture comprising oxygen-containing oxidizer gas, and post combustion of said gas mixture in a post combustion chamber, said post combustion operating to react said sulfide-rich first process gas component with said second process gas component, which acts as oxidizer gas, thereby decomposing any SO3 in the gas mixture, and exposing exit gas from said post combustion chamber to subsequent gas cooling and dust removal steps.