| The copper smelting industry has been replacing old reverberatory furnaces with energy-efficient flash furnaces. While this in itself has been a significant move towards reduced energy costs, there is yet no industry consensus as to which mode of flash smelting is optimum.; It is possible to model copper smelting, the ensuing converting step, and acid production with linear equations and inequalities. These equations include mass and heat balances, and energy and cost equations. The matrix of equations and inequalities can be entered into a linear programming routine to determine minimum costs.; Such a model has been developed and the results indicate that optimum smelting parameters include the following. (1) The grade of matte is 65% Cu. (2) The flash furnace operates autogenously with no air preheat. The flash furnace air is oxygen enriched to approximately 40 volume % O(,2). (3) Total energy cost (1985 dollars and prices) for smelting, converting, and acid production is approximately {dollar}10 per tonne concentrate.; The general model employed to obtain these optimum conditions can be modified to represent unique smelting conditions. When this is done to represent the Kennecott-Outokumpu solid matte converting concept, the resultant energy costs are also in the range of {dollar}10 per tonne concentrate. This result indicates that the concept of "flash converting" may be a viable alternative to Peirce-Smith converters.; New smelters should examine the merit of waste heat recovery as an economical unit operation. The difference in operating costs, with and without waste heat recovery, may not justify the capital expenditure required to recover the heat.; Samples from the Phelps Dodge Hidalgo preheated air, fuel-fired flash furnace, show that Fe(,3)O(,4)-FeS reactions occur both in suspension in the reaction shaft, and in the molten bath of the furnace. The data indicate that without oxygen enrichment, there is considerable magnetite formation in the reaction shaft. To a great extent, this magnetite is reduced to FeO before the slag is removed from the flash furnace. |
