Metals Extraction and Processing Liquid Analysis

My trusty Emerson RSS feed alerted me to a new liquid analysis application guide for the metals extraction and processing industry. This guide, published by Emerson’s Rosemount Analytical Liquid business, covers the liquid analysis solutions for the following processes: leaching and ore extraction, concentration and separation, finished product purification and waste disposal.

I confess to knowing little about mining and metals production processes, but after reading this application guide, I have a much better appreciation for the processes and some of the challenges.

In the leaching and ore extraction section, precious metals such as gold and silver are commonly processed using cyanide compounds. As the guide succinctly puts it:

Cyanide dissolves the precious metal by forming a chemical complex with it, thus separating the precious metal from the other constituents of the ore, which do not dissolve.

The challenge is accurate pH measurement for both safety and efficiency. pH values lower than 11 favor the formation of hydrogen cyanide gas, which is colorless, odorless and poisonous in sufficient concentrations. Continuous pH monitoring and control is critical to prevent the formation of this gas. Measuring pH is complicated by the finely ground abrasive ore which can coat and abrade the pH sensor. The guide describes the Rosemount Analytical pH probe, jet spray cleaning attachment, and measurement analyzer best suited for this application.

The guide has easily understandable process flow diagrams for flotation cell pH measurement, titanium dioxide (TiO2) manufacturing, Alumina/caustic ratio control, steel treating, cyanide oxidation and waste disposal via scrubbers. It provides a good overview description of the process, the measurement and control challenges, and the liquid analytical products that can help address these challenges.

If you’re in the metals extraction and processing industry, this guide helps you understand the products Emerson offers for a particular application. For those of us not familiar with the industry, the guide provides a great overview of some of the major production processes and the challenges engineers from this industry face.

Given recent trends in metal prices, if you’re a process automation engineer or engineering student, you may want to learn more about this industry. If you do, you’ll find this guide to be a useful overview.

Posted Monday, July 7th, 2008 under Measurement Instrumentation, Metals, Mining, Minerals.

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