Processing
Vanadium Plant
Roasting and Leaching
The roasting and leaching plant is proven technology and was utilised successfully during operation of the first Windimurra plant. As a consequence, its design is being replicated.From the magnetite concentrate stockpile located at the end of the beneficiation process, concentrate is fed into the rotary kiln where it is roasted at up to 1,200 degrees C in the presence of a sodium flux to produce water soluble sodium vanadate.
The calcined material discharges from the main body of the kiln into the planetary coolers and is then screened and crushed. The calcine is quenched and fed into one of three leach vats operating on a batch basis.
At the end of each batch the dilute pregnant solution containing vanadium is pumped out and concentrated by evaporation in the wet venturi scrubber on the kiln off gas.
Desilication and Precipitation
The vanadium rich solution (“pregnant solution”) is pumped continuously into desilication tanks where it is treated with aluminium sulphate and filtered. The solids are discarded and the clean pregnant solution is pumped to the precipitation area. The clean pregnant liquor is cooled and ammonium sulphate added. A white precipitate called ammonium metavanadate is formed which is then thickened, filtered and dried. After drying, the dried product is collected in a product bin.V2O3 Production
AMV from the product bin is then transferred through the reduction kilns producing V2O3 and then into the V2O3 silos.The precipitation and V2O3 process is illustrated in Figure 1 below:
Figure 1: Desilication Process
FeV Production
FeV Production is a batch process. V2O3, aluminium granules, scrap iron and lime are fed into the electric arc furnace in prescribed quantities. Each batch is designed to produce 2.5 tonnes of ferrovanadium containing 80% vanadium. The FeV process is illustrated in Figure 2 below:Figure 2: FeV Process