preconcept separation stages of concentrates flotation of carbon byproducts (LA29)

ISSUE

An aluminum smelter is working on a process for the flotation of Carbon By-Products (CPB) from a spent pot lining processing plant. The process aims to separate the refractory brick from carbon by-products for recovery. Pilot flotation tests were conducted in the laboratory to produce carbon concentrate from the CPB. The client also wanted to determine the solid/liquid separation technology (filtration or decantation) to treat the concentrates output from the flotation circuit.

TECHNOLOGICAL CHALLENGE

STS Canada was contacted to identify the best filtration or settling separation technologies for the flotation concentrates and to identify a method to break the carbon concentrate emulsion from the flotation units.

RECOMMENDED SOLUTION

The STS Canada has evaluated the solid/liquid separation technologies (filtration or decantation) that separate CPB produced in the flotation unit. Also, laboratory tests were part of the evaluation including the preparation of the experimental protocol and the characterization of concentrates and substrates (filtrate, sludge, overflow, underflow). The selection and recommendation of technologies were established according to design.

RESULTS

The Laboratory tests showed that the decantation was not the right separation method for the CPB concentrates. Moreover, the filtrations tests indicated that the filtration of the concentrates without polymer additions did not make it possible to reach an enough filtrates clarity. The validation has concluded the necessity to add flocculant to the concentrate to achieve the filtration in one step; and then recirculate the filtrate.