Matte Smelting Research Articles

玉野製錬所における銅製錬

Tamano Smelter was constructed as the first copper smglter of Hibi Kyodo Smelting Co., Ltd. whichwasajoint venture of three Japanese pnmary copper producers; MITSUI Mining & Smelting Co., Ltd., NITTETSU Mining Co., Ltd. and FURUKAWA Co., Ltd.The Smelter started operations in January, 1972, and has the capacity now to produce 8500 tonnes of cathode copper per month. Though matte smelting was based on the flash smelting process of Outokumpu Oy., electrodes were inserted in the settler, which made it unnecessary to provide an external slag cleaning furnace. Copper loss in slag is less than 0.6wt% Cu while copper in matte is 54%. Moreover, the adoption of water jacketed steel plate uptake could avoid the dust trouble through a waste heat boiler.Matte is treated in one of two hot converters. Converter off-gases are led to a gas cleaning section of an acid plant where flash furnace gas is combined with them. Nearly all sulfur dioxide in these gases are recovered as 98% sulfuric acid.To aim at a non pollution smelter, off-gas and fugitive gas collecting systems were installed. Converter fugitive gases which are sent to a tall stack only during out of stack times in converter operations, are sucked to the uniquely developed collection systems. A desulfurization plant using the lime process was completed in 1976 to comply with strict regulations. By this more than 99.6% of sulfur is fixed at present.Blister from converters is treated in two refining furnaces. Old refining furnaces were replaced by larger ones with unit capacity of 330 tonnes in 1975, in order to increase the production capacity, to achive higher efficiency in the operation, and to reduce the cost. For the purpose of simplifying the operation and improving the anode quality, the casting process was throughly made automated and, as the result, high quality anodes suitable for high current density electrolysis have been produced.An oxygen plant is now under construction to achieve higher efficiency in the operation and to increase the production capacity. Coal milling plant is also to be completed to cut fuel cost.The refinery started operation with a monthly production capacity of 7, 000 tonnes of cathode copper. Feature of this refinery is the use of periodic current reversal with current density of 348A/m2. Developments of special cell bus bars and an automatic short circuit pair detector were useful for power saving. Present production capacity is 8500 tonnes per month.Purification of electrolyte is done by electrowinning, evaporation using a submerged combustion burner, and crystallization of nickel sulfate.Crude nickel sulfate and decopperized slimes are sent to Takehara refinery of Mitsui Mining & Smelting Co., Ltd. for further treatment.

Thermodynamics of copper matte converting: Part I. Fundamentals of the noranda process

This paper presents a computer-oriented thermodynamic method to analyze copper matte smelting and converting, the system of which was ideally defined as consisting of five major components: Cu, Fe, S, O and SiO2. As an example of its application, the method was demonstrated in establishing a steady-state model for the Noranda Process producing either metallic copper or high grade matte. Process variables such as temperature, oxygen enrichment, charge (or concentrate) composition, matte grade and magnetite content of slag are integrated into one computer model. The model gives the chemical composition of metallic copper, matte and slag phases for any specified condition. Mathematical formulae accounting for physical entrainment in the melts are also presented to correlate the computed melt composition with that observed. The computer model can provide predictions as to the effects of operating and chemical parameters and can contribute to improved metallurgical control.

The distribution of silver, gold, platinum and palladium in metal-matte systems

The distribution of silver between molten metal and matte was determined at temperatures of 1150 to 1250°C. The partition coefficient (KAg-ratio of wt pct silver in matte to wt pct silver in metal) was 0.46 and was essentially independent of silver concentration, temperature, iron content and oxygen and SO2 partial pressures over the ranges studied. Only the presence of nickel significantly affected KAg, causing it to rise from 0.46 to 1.16 within the region of liquid immiscibility. Outside this region all silver was intimately associated with chalcocite, rather than the heazel woodite or metallics, formed during solidification. Studies on other precious metals showed that KAu=8×10−3, KPd=6×10−3 and KPt=4×10−4 in the Cu−S system at 1200°C. Application of these results to actual operations is discussed, as is the chemical behavior of precious metals during matte smelting.

Some Experiments in Prehistoric Copper Smelting

It is demonstrated that workable metallic copper can be produced by a simple two-stage process from chalcopyrite ore. This simpler process could have been in use before the more complicated multi-stage matte smelting process described in the historical documents on early technology. The simpler process would probably have been operable by any society in prehistory which possessed two-tiered pottery kilns. This simpler process may have been supplanted before recorded history by the matte smelting process because the latter permits recovery of precious metals (gold and silver).

Thermodynamic considerations of copper smelting

AbstractCombining the knowledge of the phase relations with thermodynamic calculations, the basic problems in copper smelting are discussed on the Cu-Fe-S-O-SiO2 system in terms of sulphur-oxygen chemical potential diagrams. During the matte smelting stage, the variation in the activities of Fe3O4 and Cu2O is found to be small, even though the matte is oxidized up to 70 per cent copper. However, when white metal of 70 per cent copper is oxidized to 80 per cent copper matte coexisting with molten copper, drastic variations in such activities, are observed. On the basis of these facts, reasonable explanations are given for the smelting principles involved in both the conventional and newly-developed continuous smelting processes. Dissolution of copper oxide and sulphide, and behaviour of impurities are also elucidated thermodynamically. Resume L'auteur traite du smeltage du cuivre en termes des diagrammes de potentiel chimique soufre-oxygene et des diagrammes de phase du systeme Cu-Fe-S-O-SiO2. Pendant l' e...