Stripping electric smelting furnace for refining residues

11 Ноя 2010

In 2010, OJSC Krastsvetmet launched the stripping electric smelting furnace for refining residues.


Purpose:
  • 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).
Materials for recycling:
  • 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%.
Parameters 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.
Peculiar features of the plant:
  • 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.
Results of the implementation:
  • 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.