22 Mar BiotaTec converts Phosphogypsum from waste into a new revenue stream
PROMETIA member BiotaTec operates a BioMining centre and demo plant in Estonia. The SME develops, adapts and licenses for mining/metallurgical/recycling/energy companies its various proprietary cost-efficient biomining solutions with low energy demand and low GHG emissions for the extraction of critical raw materials from low-value waste, overburden and ores.
NEW RESEARCH CASE ON PHOSPHOGYPSUM
Phosphogypsum (PG) is a waste product resulting from the extraction of phosphorus from phosphate ores using sulphuric acid. While there are many uses for gypsum in the construction industry, its content of radionuclides, mainly in the form of uranium and thallium, prevents it from being used for such applications and forces it to be landfilled. Given that 4-5 tons of PG is produced for every ton of phosphoric acid, the annual production of PG is around 300 million tons, creating ever-increasing problem for mining industry to deal with the build-up.
At the same time, phosphate rock sediments contain significant amounts of rare earth elements (REE-s), of which about 85% are concentrated in the PG, making this material a rich source of various REE-s with concentrations of up to 5000 ppm-s. Conventional extraction methods are unprofitable due to the very high energy requirements and the use of large quantities of hazardous chemicals (e.g. concentrated mineral acids). However, given the content of REE-s in PG, an economically feasible method would provide enough REE-s from PG to meet global demand and drastically change geopolitical control over resources.
A BIOLEACHING-BASED SOLUTION FOR RARE EARTH ELEMENTS
BiotaTec has developed a novel bioleaching-based solution termed BiotaREEP for REE extraction and convert PG from waste into revenue stream. In general, bioleaching employs normal metabolism of microorganisms to separate metals from different solid materials, e.g., low-grade ores or waste streams. It operates usually between 30°-37°C and has therefore much lower energy requirements. Unlike old-fashioned solutions that could extract a limited number of metals from sulphide-rich ores, BiotaREEP is a Next-Generation bioleching solution that is capable of recovering a number of different REE-s such as Ce, La, Nd, Gd and Dy. Furthermore, it also resolves one of the biggest problem in bioleaching, that is long leaching times, being capable of isolating 60-90% of REE-s in as short time as in 1 hour.
This solution is also developed to be applicable for heap leaching as it would significantly cut the costs of the whole process negating the need for stirred reactors. Approximately 90% leaching efficiency with 6 hours in the case of 20% pulp density has already been reached and trials with modeled heap-leaching unit are planne dto start within a year.