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Golden Sibanda, Harare Bureau

PROSPECT Resources, developer of the Arcadia lithium plant near Harare, will build a smaller commercial scale pilot plant for only one of two locally available lithium varieties, as the route is a lower risk pathway to near term production.

Lithium mining was designated as an integral part of the Government’s US$12 billion mining industry target by year 2023 and this strategically key sector is expected to earn US$500 million annually by that time.

The Australia-listed miner earlier announced that it had commenced the development of a pilot plant to produce both petalite, which is technical grade and spodumene, (chemical) grade lithium samples.

Prospect has now decided to focus the pilot plant on producing only technical grade petalite samples using dense media separation (DMS). The latest alternative is in accordance with Arcadia’s existing Feasibility Study flowsheet rather than producing both petalite and spodumene samples using a flotation flow sheet.

The DMS Feasibility Study flowsheet, Prospect said, has been proved to have greater technical certainty than the flotation flowsheet. The pilot plant is expected to produce and ship samples in the 2021 first half. The lithium produced at Arcadia goes into both technical (glass and ceramics) and chemical (vehicle and electronic batteries).

“The DMS flowsheet is considered the lower risk pathway to near-term production as determined through detailed analysis by management and a number of external third-party experts,” Prospect said.

Petalite, as a proportion of the Arcadia mineral endowment, is significant and increasing the recovery of petalite and maximising sales into the global technical market is an important strategic objective as the project progresses.

Prospect has already signed offtake agreements with buyers in Europe and other markets for its lithium output but must submit samples to determine whether its produce meets technical specifications.

To qualify petalite with potential customers the company must provide samples of up to 100 tonnes per customer. Samples of this size are most economically produced in a pilot plant. By contrast, customers only require two kilogramme samples to qualify the company’s spodumene products and these can be readily produced in the laboratory.

Prospect said the flotation flowsheet process was expected to be the preferred flowsheet procedure in time. However, there is limited commercial knowledge at this stage on petalite flotation.

As such, a more detailed assessment has revealed that the metallurgical process requires complex staging, with different water regimes and significant reagent blends, some of which require very specific hazardous handling procedures.

The production and export of petalite produced by the pilot plant will test the readiness of the regulatory and fiscal regime (including the Special Economic Zone) that will apply to the commercial operation.

This “commercial road-test” is expected to de-risk this element of the project for lenders and investors by demonstrating sales receipts through the offtake agreement and the ability to deal freely with foreign currency receipts.

The operation of the pilot plant will allow for the accumulation of knowledge during design, mitigating the scaling issues that peer lithium producers have experienced on account of a too rapid growth in supply. The petalite flotation increases flowsheet risk, increases capital and operating cost against initial

assessments, and would require considerable time and effort to fine tune and perfect for use in a commercial operation.