Mining giant Xstrata’s proprietary smelter technology, Premus, will be installed at its ongoing Lion ferrochrome complex Phase 2 expansion project, owing to its success at the company’s Lion Phase 1 and Lydenberg ferrochrome smelters.

The company claims that Premus reduces its overall ferrochrome production cost by about 6%, and consumes about a third less electricity than other available smelting technologies, at an average of between 2.2 MW/t and 2.4 MW/t.

The Japanese-engineered technology has been modified by Xstrata, states Xstrata Alloys technical manager of eastern operations Oomeshni Naiker in a report, ‘The development and advantages of Xstrata’s Premus process’.

While Naiker acknowledges that its capital cost is higher than that of conventional processes, Premus remains the lowest capital cost per annualised ton of alloy compared with alternative environmentally acceptable processes available.

Naiker says Xstrata has altered the raw material requirements to a mix that is more suitable, cost effective and readily available.

“Xstrata uses anthracite in its furnaces to replace the expensive and scarce coke, a reductant required by almost all ferrochrome production units,” she says.

Further, Naiker points out that the technology results in significantly better efficiencies than conventional operations, and also facilitates low coke consumption, 100% agglomeration and low silicon production, compared with the typical charge chrome silicon content of about 4%.

Coke consumption of conventional processes languishes at about 60%/t, while Premus boasts a reduced coke reliance of 20%/t.

Meanwhile, a significant feature of Premus is its decreased dependence on electricity for effective operation, a distinct advantage in view of uncertainties regarding State-owned utility Eskom’s capacity.

Merafe Resources, Xstrata’s joint venture (JV) partner in the Lion ferrochrome complex Phase 2 expansion project, is reluctant to divulge the specifics of a recently finalised user agreement between the JV and Eskom, but emphasises the advantage of Premus’s reduced energy requirements.

“While rising national electricity costs will impact on production cost, the effect on Merafe would have been far more substantial had we not invested in this technology,” says Merafe finance and investor relations manager Kajal Bissessor.

The technology also has promising indus- try best practice environmental results, which further drove the resolution to install it at Lion 2.

“The use of our energy efficient Premus technology for the expansion project will expand Xstrata’s cost leadership in a global environment of escalating energy costs. The project is further aligned with some of the key principles of government’s Integrated Resource Plan, “ says Xstrata Alloys CE Peet Nienaber.

Further, the technology offers decreased emissions compared with conventional processes, notes Xstrata Alloys Project Lion safety, health, environment and quality manager Frank Cotton, with fewer greenhouse-gas emissions as a result of lower energy consumption, and the reuse of emitted carbon dioxide as an energy source.

This reduces the operation’s carbon footprint and the resultant carbon tax.

At a site visit earlier this year, Merafe underscored the significance of Premus as a proprietary technology that is difficult to emulate and retrofit, and requires a high level of operational knowledge.

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