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Mining and metals refining
Jul 5, 2017

Outotec burners in the copper heart of Bulgaria

Bulgaria's integrated copper smelter and refinery, MDK, was founded in 1958 with a design capacity of 60,000 tpy of cathode by Bulgarian and Soviet engineers using their original technology.
Samples from the flash smelting furnace

n the 1980's a decision was made for plant production expansion and modernization. A totally new smelter designed by Outokumpu and its partners Rauma-Repola and Ahlstrom was commissioned in 1987. The plant originally consisted of the following equipment:

  • Two rotary kiln dryers;
  • Flash Smelting Furnace equipped with four concentrate burners and settler dimensions of 29.5m L by 8.7m W by 3m H;
  • Waste Heat Boiler;
  • Three Pierce-Smith Converters, 3.92 m by 9.24 m,
  • Two Anode Furnaces, 3.22 m by 9.12 m
  • One 24 Mold Anode Casting Wheel with an Outokumpu double pour system.
  • One Single Contact Acid Plant and One Double Contact Acid Plant.


After ten years of successful operation, in 1997-1998 a study of the existing process was completed. Based on that study, a modernization program was developed and implemented in a three-month shutdown period during the last quarter of 1999. The project included:

  • Complete rebuild of Flash Smelting Furnace  including major improvements to water cooling systems;
  • A Loss-in-Weight feed system was engineered and installed by Outokumpu;
  • A single jet concentrate burner;
  • Complete rebuild of the Waste Heat Boiler

The first year of operation after the modernization exceeded all expectations. In addition to a virtually trouble free start-up the plant increased copper production with almost 140% versus the originally anticipated. After the modernization several investment programs have been done aiming at improving the plant’s environmental performance and production efficiency.

The single jet burner, which is today situated in front of the smelter administrative building as a monument, is the one installed in 1999. After 13 years of successful operation and 12 213 334 tons of processed blend, the single jet burner was replaced with the most recent Outotec single jet burner in 2012.

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