Monday, 10 November 2014

The need to conserve water resources

Sustainability was a major feature of last month's IMPC in Santiago. Reducing energy consumption is of major importance, but managing and reducing water consumption is now recognised as being of equal importance.
In a timely article in Minerals Engineering, CSIRO authors stress that maintaining the integrity of the local environment and ensuring a secure supply of water should continue to be the focus for water management at individual operations. At a corporate level there is a growing need for improved understanding and recognition of a company’s reliance on indirect water, and the risk factors that occur from operating in different regions. Nationally and internationally, accounting for water impacts can assist in ensuring global demands for mineral and metals are met with minimum impact on water availability and security. The study shows that the results of water footprint based analysis can be used to identify opportunities for process improvements, to prioritise water efficiency and guide infrastructure investments. Building resilience to water risks by understanding and managing direct and indirect water use will reduce the overall water supply risks facing a business, particularly when operating in water stressed regions.
Due to scarcity of fresh water and stringent regulations on the quality of discharged water, more and more flotation plants have to use groundwater, sea water or recycle water with a high concentration of electrolytes. Although a number of studies have been conducted to investigate the effect of saline water (or salt solutions) on mineral flotation, effective ways to solve the problems encountered in mineral flotation plants using saline water are currently not available. In another recently published paper workers from the University of Queensland review published articles addressing the effect of saline water on the interfacial phenomena taking place in the flotation process, such as surface wettability, bubble-particle collision and attachment, mineral particle interactions and frothing. The review provides an overall picture of the current status of studies in this area and pinpoints directions of future research to address different problems associated with using saline water in mineral flotation.
I invite your comments on these important papers.

4 comments:

  1. From the abstract of the water footprint article, I think it's a good thing a study is quantifying the effects of water usage in the minerals industry, as it does make it easier to analyse and seek ways to optimise water usage.

    It was interesting to learn saline water helped with coal recovery, but then saline water helps with leaching for some types of minerals. Although I'm curious about the possible effects the salt will have on downstream processes (effects from more iron ions in solution, corrosion, changes in efficiency, ect), final products and treatment when it comes to releasing that water to the environment.

    Kate Siew, Australia

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  2. If we accept that the ever larger tonnages of ever lower grade ore also require ever larger volumes of water, then machine sorting of dry ROM ore (to reject below cutoff grade rocks) prior to mineral dressing should become a priority.
    Gus Van Weert, Canada

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    1. I totally agree, Gus. Sorting will play an increasing role in future mineral processing plants, to reduce energy consumption in comminution and water usage. This will be the theme of Rob Morrison's keynote lecture at next year's Physical Separation '15 conference- "Reducing energy consumption in comminution by doing much less of it!"

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