Slag fuming

Cadmium Roasters, slag, fuming furnaces, deleading Idlns Particulates Local exhaust system, baghouse or precipitator... 

Indium may be recovered from zinc ores by several patented processes. Usually it is recovered from residues obtained from zinc extraction. The residues, slags, fume, or dusts from zinc smelting or lead-zinc smelting are treated with a mineral acid. Other steps involved in recovery often vary, but mostly use solvent extraction and precipitation steps. In some processes, treatment with caustic soda yields indium hydroxide. The hydroxide is calcined to obtain oxide, which then is reduced with hydrogen at elevated temperatures to obtain the metal. Distillation or electrolysis are the final steps to... 

Other processes include an electrothermic process, an electric-arc vaporizer process, and the slag fuming process. 

In lead smelting, the oxygen-enriched blast has been used in lead cupola and slag fuming furnaces. Oxygen enrichment of the copper blast furnace is also common. 

Feed Grade Pb Content % Ten ) Smelting C Direct Recovery To bullion Smelting Slag Grade % Distribution % Slag Fume Overall Pb Recovery with fume rccycl. (%)... 

The first feed went into the KIVCET furnace on March 31, 1997. The start-up of the new slag-fuming furnace was three months later in June 1997. The initial period of operation was hampered by mechanical problems that prevented sustained periods of operation imtil a major shutdown in November 1997 when several mechanical deficiencies were corrected. This... 

The complex system of recycle streams betwe i and within each of ftie operating units ensures a higih overall recovery of the major products. For example, lead, bismuth and precious metals are recovered firom both the lead concentrates and the zinc concentrates treated. Recovery of lead is also significantly enhanced by operation of ftie slag fuming and oxide leaching circuits. Lead not recovered directly to bullion in the KIVCET furnace is recycled... 

With increased focus on the recovery of metal values in stockpiled slags and residues, impurity control becomes an even more important consideration. Operation of the KIVCET furnace at design capacity and the restart of one of the older slag fuming furnaces have enabled treatment of these stockpiles. As the stockpiles were being accumulated they formed natural bleeds for undesirable impurities such as the halides, and now the challenge will be to control... 

There is only one day of capacity between the zinc fume recovery process in the smelter and the fume leach process in the zinc plant. Therefore, if there is an upset in the leach circuit, it is necessary to stop the slag fuming process for zinc recovery and stockpile smelter slag for recovery in the future. The same is true for the flow of residue from the zinc plant circuits to the smelter. Residue slurry is transported from the zinc plant to the smelter, where it is... 

THE QSL LEAD SLAG FUMING PROCESS USING AN AUSMELT FURNACE... 

The production of indium and germanium products is important, and as was expected with the start-up of the KIVCET furnace and a new slag fuming furnace, the production has been expanded. The associated indium-germanium plant has now the capacity to produce 60-70 totmes of refined indium and 30-35 tonnes of contained germanium in germanium dioxide. Further expansion of germanium production is planned and will be implemented as necessary to match demand increases. 

Final slag is below one per cent Pb and contains between seven and 15 per cent Zn and around 22 - 29 per cent Fe, 23 - 25 per cent Si02 and 20 per cent CaO, and is sent to a slag fuming furnace to recover zinc. 

The Kivcet Process (an acronym in Russian for oxygen flash cyclone electrothermal process), was developed by the Vniitsvetmet Institute in Kazakhstan in 1967 for the treatment of both copper and lead concentrates (Sychev et al, 1985). A 25 t/d pilot plant was built and operated for a number of years followed by a plant to treat 500 t/d of mixed copper-zinc concentrates at Glubokoe in 1970. That plant produced a copper matte and zinc rich slag for slag fuming in the electric furnace to recover zinc oxide. 

From Table 7.4 bullion with less than 0.5 per cent sulfur can be achieved as well as slags containing around one per cent lead. However, where slag fuming facilities are available for zinc recovery, low lead levels can be sacrificed for furnace throughput as in the case of the Teck-Cominco owned Trail plant. The lead content of slag will be almost fully recovered with the zinc oxide fume and will be recycled in the form of zinc plant leach residues containing lead as lead sulfate. 

---