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Summary
The "past, present and future" of this technique of copper production in the western United States, and the downstream method of metal recovery via solvent extraction/electrowinning, is described* by Gerard PGillen, National Sales Manager of ASARCO Incorporated, Tucson, Az.Abstract
The copper-producing industry was in very poor condition in the early- to mid1980s due to high costs and low selling prices. In order to reduce costs, many uneconomical plants and ..mines were closed; and research efforts were-undertaken to improve technology. Producers upgraded the known processes involved in sulphuric acid leachingsolvent extractionlelectrowinning (SX/EW), and this lower cost method of production took hold and grew rapidly.
This presentation will concentrate primarily on the western United States - Arizona, New Mexico, Texas and Utah - and it will address copper production resulting from leaching with sulphuric acid as opposed to the smelting process.
Summary
The basic Claus process, now 112 years old, has undergone many modifications and almost endless process unit additions, in attempts to improve its overall sulphur recovery efficiency. This series paper by J. B. Hyne and B. ' Gene Goar is meant to provoke new thinking and discussion about "revisiting" the fundamental concepts of the process and pursuing genuinely new and novel ideas for improved recoveries -in the range of 99+% to meet ever more stringent emission regulations. Some major units to be "revisited" are: (1) the upstream SRU feed preparation, (2) the Front End Furnace, (3) the Waste Heat Boiler, and (4) the Caalytic Stages. Can industry achieve these process improvements by consolidation rather than more additions?Abstract
We are "revisiting" the fundamental principles of a process that has served the industry well, both in its early manifestations and as it has been modified and added to over the last half century or more. These additions have been driven by the need to achieve ever higher sulphur recovery efficiencies, not so much to produce more sulphur, but to reduce the amount of it that eventually becomes a toxic emission to the environment. The industry has achieved remarkable success in this endeavour. Overall recovery rates in the 70% range in the 1950s have been increased to remarkably high 90% values in the 1990s. But still the demand for squeezing out the last tenths of a percent continue, and the competition between processes is now one of getting from 99% to 99.9% or better in the most economical manner possible. Anything is possible if you throw enough money at the problem. But recovering additional sulphur at a cost in excess of $2,000/ton, when the commodity sells at less than $50-1001 ton, is not viewed by business as being "economical". The environmental price of doing business may indeed be a valid charge against the bottom line, but minimizing that charge is always warmly received by the shareholders!
Summary
Continuing our historical survey of sulphuric acid technology.Abstract
As mentioned in the first part of this article, the contact process for manufacturing sulphuric acid was not developed into a workable embodiment for 40 years after it was first proposed. One reason for the long gestation period was partly that there was already a tried and tested procedure - the chamber/tower process which could provide sulphuric acid suitable for all the purposes that demanded it at the time, so why change to something untried? The other was the rather inadequate state of scientific understanding of the physical chemistry of equilibrium reactions and catalysis.
Summary
The Sulphur Institute (TSI) held its fifth biennial symposium, "Sulphur Markets - Today and Tomorrow" in Washington, DC on 27-29 March 1996*, writes Martin Horseman, who joined over 150 marketing and technical representatives of the s-ulphur industry at the international gathering.Abstract
Sixteen speakers presented papers on a broad range of sulphurrelated topics, including:
Also discussed were prospective and emerging sulphur markets, including sodium sulphur batteries and sulphur lamps.