Development of an innovative production technology for production of ferroalloys with silicon and aluminium on the basis of industrial wastes, especially from mining industry

The main novelty of the developed production technology of complex silicon and aluminium alloys FeSiAl is the use of arc-resistance six-electrode furnace in the process and the use of industrial wastes from hard coal mining or other branches of industry (e.g. energetics, being a carrier of FeSiAl alloys basic elements) as the main material. Post-production wastes used in the innovative technology developed, created during extraction and processing of hard coal or its burning, include in their composition silica (SiO2) and aluminium oxide (Al2O3) at the same time, and in mining wastes there is also a reductor in a form of hard coal. Replacing primary raw materials containing aluminium oxides with a waste brings technological benefits of natural mixing of chemical compounds in the waste, what with a large surface of contact of elements carrier and reductor allows for decreasing the energy intensity of the reduction process, in comparison to energy needs during reduction of particular chemical compounds included in separate materials. The use of waste materials gives the huge economic advantage over the use of primary raw materials. For instance, a tonne of Al2O3 oxide coming from waste is approx. three times cheaper than a tonne of Al2O3 coming from the basic, widely used alumina-bearing natural resource – bauxite. Lowering the production costs in this way translates into final price of produced alloy. Innovative use of the arc-resistance six-electrode furnace ensures optimal temperature distribution in the furnace basin and effective use of the energy what guarantees producing of the assumed alloy with preservation of the best technical and economic indicators. It is an innovative production method, never used anywhere in the world before.

An advantage of the technology developed is:

• achievement of optimal technological and economic production indicators thanks to the innovative use of arc-resistance six-electrode furnace,
• possibility of the functional use of waste materials, mostly from the mining industry,
• lower energy intensity of a complex alloys smelting in relation to energy intensity of the separate high-grade silicon and aluminium alloys production,
• better utility properties of a complex alloy in comparison to use of ferrosilicon and aluminium in deoxidation processes and introducing alloying additives to steel and cast iron, which are manifesting themselves by less aluminium dross (losses) in those processes.