In 2010, OJSC Krastsvetmet launched the stripping electric smelting furnace for refining residues.
Materials for recycling:
- recycling using the stripping melting of the refining process residues (slag, crucible shards, kiln barrings, various compounds of non-ferrous metals) containing noble metals (platinum-group metals, gold and silver).
Parameters of the plant:
- return slag of the refining process received as a result of melting of various products. The slag is based on sodium-, calcium -, magnesium- and iron silicates and aluminosilicates. The grade is 2 mm to 40 mm, humidity – less than 5%.
Peculiar features of the plant:
- capacity – not less than 2.5 tpd;
- temperature of melted slag in operational conditions – from 1200oC to 1350oC;
- operational volume of the furnace melting zone (up to the discharge hole) – not less than 500 liters;
- operating mode – continuous (with periodical feeding of blend, filling a pot, sedimentation of melt, dump slag discharge, target precious metals melt discharge when it is accumulated);
- discharge of depleted slag is done through the discharge hole by tilting the furnace;
- discharge of target metal or a full discharge of melt from the furnace (before its shut-down) is done through a taphole.
Results of the implementation:
- possibility to recycle a wide range of materials, the residues from the refining production;
- obtaining of slag with a high content of precious metals (silver: less than 100 g/t; total platinum-group metals: less than 50 g/t);
- obtaining of a bottom alloy with a high total content of precious metals – not less than 50 %);
- simple gas treatment system due to small off-gases volumes and low dust loss (the off-gases volume depends on the aspiration as the gas release from the blend itself is low);
- strong lining due to not high melting temperature and no electric arc;
- interlocking and alert system operation in case of abnormal and emergency situations;
- possibility of complete or partial automation of the production process;
- the furnace has a certificate of compliance of the equipment for use at hazardous facilities.
- lower precious metals content in the production residues - down to the tenths of a gram per tonne;
- less materials in process and higher direct precious metals yield.