By Sarah Pridgeon
A successful pilot plant test program conducted in Canada has validated the benefits of Rare Element Resource’s innovative new processing technology, the company announced last week.
“Our pilot plant testing was an unqualified success not only in demonstrating on a larger scale the benefits of our process in the critical metrics of achieving high bulk concentrate purity, excellent recoveries and substantially reducing reagent costs, but also in identifying additional opportunities for improved efficiencies and cost savings,” says Jaye Pickarts, COO.
The proprietary process will both improve the yield from the proposed rare earth mine and increase its efficiency and financial prospects, says George Byers, Vice President.
“The processing technology was developed by RER. With new technology, you usually test it on a small scale, called bench scale testing,” he explains.
“The pilot plant testing proved we could successfully scale the process up. It also allowed us to make some adjustments to get even better results: 97 percent instead of 93 percent bulk concentrate purity.”
The testing has provided design criteria that will now be used in the detailed engineering portion of the Feasibility Study. It identified key advancements, including the ability of the company’s technology to separate rare earths from base metals using selective precipitation, in a single step process.
”The advantages of a single step process usually translate into lower capital and operating costs – but, equally importantly, more efficient operations,” says Byers.
During the testing, various rare earth elements responded well to acid digestion, which will allow leaching efficiencies that average 95 percent. This will contribute to high overall recoveries averaging 85 percent in a combined physical upgrade and hydrometallurgical process.
“Leaching efficiency specifically refers to the amount of REE extracted from the ore,” says Byers. “The quality comes from the ability to eliminate impurities, which is related to other steps in the process.”
The plant will have the capacity to regenerate and recycle the acid reagents used in the process, which will lead to an anticipated reduction in raw material costs of approximately 50 percent. The recycle process will eliminate process effluents, which reconfirmed that there will be zero discharge from the facility.
“Zero discharge means that none of the reagents used in the hydromet process are discharged into the environment. The amount of effluents will have been reduced significantly by recycling and those that remain in the ore would be stored in a lined, engineered, contained tailing facility,” says Byers.
The new process also allows Thorium and Uranium to be isolated from the residual solids and final bulk concentrate, which will allow for easy third party disposal. This, according to the company, is a significant advancement in the treatment of radionuclides in rare earth mining and a provisional patent has been secured for the process that may allow RER to market it at some point in the future.
“This will allow us to have a final product that contains negligible amounts of thorium or uranium, something that is required by our potential customers,” says Byers.
“We expect that this new process could potentially be more cost effective than the conventional process we were originally contemplating. Additionally, by isolating the thorium, we can easily dispose of it at an off-site, licensed disposal facility.”
The process will also offer the opportunity for RER to isolate naturally occurring, potentially valuable by-products such as aluminum, iron, calcium, manganese and gold. These may represent an opportunity for additional revenue streams.
“To beneficiate any one of these elements would require additional processing. That’s why work still needs to be done to determine the cost/benefit of any potential recovery,” says Byers.
“We haven’t made any decisions. We are just pleased that the process affords us the luxury of looking at these options.”
Due to the purity of the concentrate that can be created with the proprietary process, RER will be evaluating downstream elemental separation for the additional value it could bring to the project, says Pickarts.
“We will begin evaluating the technology alternatives for separation and assessing end-user needs to determine the most attractive product mix,” he says.