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A new method for treating wastewater from mining that involves magnesium and aluminum is being investigated by a Singapore-based company.
Water Online reports that Scalada Holdings, Ltd. will look at how aluminum and magnesium-layered minerals called hydrotalcites form when the two substances exist in the proper ratios during the neutralization of acidic water.
“Mining wastewater already holds high magnesium and aluminium concentrations. Hydrotalcites can be created by simply adjusting the ratio of pollutants that already exist in the mining wastewater, and adding alkaline compounds to alter the pH level as required” said Manly Logan, Scalada Holdings CEO.
The process differs from traditional lime-based methods of decontaminating wastewater, and has the advantage of using less water in the process, since the decontaminated wastewater can be re-used at the mine, according to the company.
Australian Mining earlier this year described a similar process being tested by Australia’s national science agency, CSIRO, which stands for Commonwealth Scientific and Industrial Research Organisation.
It said the process initially focused on extracting uranium from wastewater, but also removed such contaminants as rare earths, transition metals, metalloids and negatively charged molecules like arsenate.
“This process purifies the wastewater from mines in a faster, more effective way that does not require large amounts of infrastructure or difficult chemistry to achieve it,” said Dr. Grant Douglas, CSIRO senior principal research scientist, as per Australian Mining.
Market update
Prices for Chinese magnesium have notched up due to reduced stocks, Metal-Pages reported on Monday. In the past two weeks, the price of 99.9% magnesium metal has moved from RMB 15,000 to 15,500 per tonne ($2,461 to $2,543) to RMB 15,300 to 15,800/t. ($2,510 to $2,592)
A source quoted by Metal-Pages said there are only “a couple of hundred” tonnes of magnesium stocks in warehouses and that there is very little inventory pressure.
Prices in the United States were unchanged, with 99.9% magnesium being delivered in the range of $2.10 to $2.25 a pound.
In Europe, the magnesium market strengthened in line with developments in China, the key supplier to Europe, Metal-Pages said, with magnesium on the spot market being delivered at between $2,725 and $2,775 a tonne. European magnesium prices are at a four-year low and well off a peak of $3,325 a tonne in January when China abolished export duties on magnesium.
China is the dominant force in magnesium production, accounting for 83 percent of world supply, with over half of the metal ending up in magnesium alloys and the rest used to make beverage cans, according to industry data.
Securities Disclosure: I, Andrew Topf, hold no direct investment interest in any company mentioned in this article.