Water is a significant resource on which several industries are dependent and that needs to be utilized more cautiously. One of the best examples is the beneficiation of mineral ores. Taking the raw material fluorite as the illustration, scientists at Helmholtz Institute Freiberg for Resource Technology (HIF) have now proven that how water usage can be improved. Thus, they have made a new process that ranges the simulation of the beneficiation procedure. It specifies the conditions in which it creates a sense for water to be reused without suffering losses over the period of ore enrichment.

Freshwater consumption can thus be considerably reduced. This not only aids the environment but then also the mining establishments. As it makes the process of raw materials extraction even more effective. The scientists have offered their innovative procedure in the Journal of Environmental Management. In addition, HIF is a division of Helmholtz-Zentrum Dresden-Rossendorf as well as works in close association with TU Bergakademie Freiberg.

Originate in modern cars, smartphones, environmental-friendly photovoltaic units. This is also used in several other businesses, the automated tool has become an indispensable component of routine life. Though recycling can partly cover the demand for raw materials, the maximum is yet obtained from mining. The environmental influences are very well known. Land use, the generation of additional traffic infrastructure as well as industrial development of most remote regions. Mining also necessitates huge quantities of water, also produces a large amount of wastewater. Functioning in partnership with colleagues in Finland, a team of scientists at HIF run by process engineer Bruno Michaux has established a technique of creating water usage in the treating of mineral raw materials more viable. Taking the mineral fluorite as an instance, they have proven how water consumption can considerably be decreased.

Fluorite

Fluorite — also identified in mineralogy as fluorspar along with its chemical name of calcium fluoride — is a significant raw material for the establishments. It is used, for instance, in the in aluminum extraction, smelting of iron and in a chemical segment as a raw material for the production of fluorine & hydrofluoric acid. Perhaps the best-known manufactured goods of fluorine chemistry are PTFE, a fluoropolymer that is sold in membrane form in the trade names Teflon & Gore-Tex.

“The extraction of fluorite consumes a lot of water,” describes Bruno Michaux. “Depending on the local climate, but even more so on the design of the mineral beneficiation plant, it can be up to 4,000 liters per tonne of ore”. There is visibly nothing that the HIF scientists can do regarding the weather. Yet they can surely contribute towards optimizing the treating itself. In this step of the procedure, waste rock is detached from the extracted ore to increase the fluorite content from around 50 % to approximately 98 %.

Flotation procedure

To achieve this, the engineers put on the flotation procedure. In other words, it generally works as: the ore is ground & mixed along with the huge amount of water; then several chemicals are added to the mixture in order to render the fluorite surface water-repellent (hydrophobic).

Then the air is pumped into the said mixture, making small bubbles that transmit the hydrophobic elements to the surface. The fluorite hence collects in the resultant foam whereas the waste rock is left behind. Before the latter can be dumped on a waste dam or else given back underground as a filling material, a dewatering step is required. To attain the preferred concentration of fluorite, flotation is a repeated number of times. That accordingly requires a lot of water.

“Mining companies are trying to reduce their consumption of water by using it multiple times,” states Michaux. “However, used water contains substances that can interfere with the process performance, and that is something to be avoided.”