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Shaft furnace

Process Description

In the shaft furnace the feed material flows from the top to the bottom of a perpendicularly positioned oven chamber. The energy for the smelting process in the shaft oven is created mainly through the combustion of coke. The copper containing raw material is transformed to “copper matte" with a copper content of 55 - 60 % mainly from Cu2S. Shaft furnaces are used for primary and secondary copper production.  

Gas Application

The combustion air necessary for the process is enriched with oxygen and introduced into the region of the melting zone via tuyeres or wind nozzles. To ensure the predetermined oxygen content in the combustion air, the controls of the oxygen supply communicate with the furnace controls.  Messer’s Oxijet-supersonic lances, which feed the oxygen directly into the furnace, are used. The controlled Oxijet process was developed in order to be able to accurately control oxygen levels even at supersonic entry.

Oxygen enrichment creates the following advantages when used with a shaft furnace:  

  • Reduction in coke rate
  • Improved performance
  • Reduces post-combustion burden
  • Faster reaction speeds
  • Greater flexibility
  • Raised temperatures in the melting zone
  • Even temperature distribution across the shaft cross-section
  • Lower production costs
  • Lower emissions

Oxijet-technology has been installed over 40 times in cupola and shaft furnaces, with 3 of these in the copper industry.  

Messer Solution

In addition to the gases required for your process, Messer offers a variety of equipment for its optimisation under the brand names Oxipyr and Oxijet. 

In order to select the optimum system, experts from Messer first carry out a comprehensive process analysis. Following calculations and basic engineering, suggestions are made for optimisation and further procedures.

Controlled (Pulsating) Oxijet

Oxygen is introduced directly into the furnace via lances with the oxygen exit velocity in the supersonic range. The lava lances used only generate the required impulse when there is a defined design point. Pulsation guarantees consistent oxygen content in the air/oxygen mixture. 

Oxipyr – Burner Technology

Oxipyr-burners shorten the cold start time of shaft furnaces.  

Oxipyr-burners are used in combination with dust feed systems. Dust feed lances and high momentum burners together form one unit.   

Advantages:

  • Higher combustion efficiency
  • Higher melting rate
  • Faster heating-up times
  • Lower fuel consumption
  • Higher processing temperatures possible
  • Faster reaction speeds
  • Lower exhaust gas levels
  • Less dust
  • Lower emissions
  • Lower production costs

The characteristics of the burner types are multi-faceted and range from low to high momentum burners, oxyfuel to oxygen/air mixing burners and burners for different fuels or fuel combinations. The systems are controlled manually, semi- or fully automatically following compositions or temperature.