Monitoring of the mercury removal process at sulphuric acid production plants

INTRODUCTION

Sulphuric acid is an important byproduct at zinc and copper plants. Copper and zinc ores often have elevated mercury content. During heating in the process of roasting, mercury is evaporated from the ore and, if not removed, will finally appear in the sulphuric acid. The elevated mercury content in sulphuric acid that is further used in the food and other industries is not permitted, so various mercury removal methods are used in the sulphuric acid production process.

Mercury removal from the roast gases may be effectively controlled by the RA-915M/RA-915AM mercury analyzers, as its distinctive feature – Zeeman background correction of the nonselective absorption – allows mercury determination even in the presence of high contents of SO2. Thanks to this fact sulphuric acid manufacturers can monitor the efficiency of the mercury removal process on-line, and take action before mercury contaminates the final product.

Furthermore, the mercury concentration in the final product – concentrated sulphuric acid – may be easily controlled by a conventional cold vapor technique using RA-915M mercury analyzer with RP-92 attachment.