Modern Mining November 2021

LITHIUM AND TANTALUM

to the tin bearing mineral cassiterite and is currently recovered as part of the tin concentrate. At present, the company does not receive a credit for the contained tantalum within the tin concentrate. Therefore, the aim is to separate the tantalum bearing minerals from the tin concentrate and create a by-product at a typical sale- able grade of 20% Ta 2 O 5 . Magnetic separation is a proven technology for the separation of Ta-bearing CGM from non-mag- netic minerals such as Cassiterite. Following the initial focus on wet mag- netic separation techniques, recent work investigated dry magnetic separation techniques. Production of concentrates containing in excess

of 24% Ta 2 O 5 was achieved from separate samples submitted to two independent service providers using similar processing strategies and equipment. Based on the results, the company will proceed with the implementation of a pilot beneficiation cir- cuit to further process the currently produced tin concentrate employing dry screening and a high intensity dry electromagnetic separation to produce a separate tantalum concentrate. The circuit has an estimated capital cost of £300 000 and will be funded from existing cash reserves. Construction of the circuit will be managed by AfriTin’s in-house engineering team. The pilot tantalum separation circuit will treat the entire stream of currently produced tin concen- trate. The company expects to progress seamlessly from the pilot phase to the final circuit configuration through process optimisation over a period of six months. 

be followed by the implementation of the full-scale petalite concentrate circuit. Tantalum by-product development Tantalum at Uis occurs primarily within Columbite Group Minerals (CGM) which have a similar density

AfriTin is encouraged by the rapid progress on its metallurgical test work programme.

Key takeaways  Metallurgical test work results at Uis Tin Mine have confirmed production potential of separate saleable lithium and tantalum concentrates  Density-based lithium beneficiation test work has achieved petalite con- centrate grades in excess of 4% Li 2 O and within contaminant specifications for a typical saleable technical grade petalite product  Test work has been successful in producing a high-grade, saleable speci- fication tantalum concentrate (>24% Ta 2 O 5 )  The pilot lithium beneficiation plant is expected to cost £2,2-million, con- sisting of CAPEX and operating costs over the course of the pilot campaign

20  MODERN MINING  November 2021