Processing of dust materials from Indian copper plants

In the pyrometallurgical processing of copper are, there is considerable amount of copper losses in the form of dust from the roaster, smelter and converter. Most of this dust is simply charged back into the smelting cir¬cuit, thereby reducing the capacity offresh charge processing. In the present paper separate processing of copper dust sample by sulphuric acid leaching method has been examined with the idea that the resulting leached cop¬per sulphate solution can be used as electrolyte in the copper electro¬refining section of the plant. The copper dust sample from Khetri Copper Complex, Rajsthan contained about 22% copper. The XRD analysis of the sample revealed that copper was mainly present in the forms of ox¬ides, sulphates and sulphides. Simple water leaching of the dust sample dissolved copper to the tune of 30%. This implied that about 30% of cop¬per was present in the sulphate form and rest of the copper was in the oxide and sulphide forms for which acid leaching process might be suit¬able. Sulphuric acid leaching at various concentration and at varied solid : liquid ratio, time and temperature were carried out at atmospheric pressure. The maximum recovery of copper obtained in these experiments was found to be about 52%. Since the sulphuric acid leaching at atmospheric presssure did not yield good results, the dust sample was leached at higher pressure in an autoclave on 200 g scale and the recovery of copper improved to 80%

Reduction of Emission from Aluminium Industries and Cleaner Technology

Aluminium metal is produced by electrolytic reduction of alumina in cells lined with carbon blocks. During the process of smelting different gaseous emissions like PFC (per flurocarbon).HF PAH (poly aromatic hydrocarbon), CO2, SO„ particulate matters etc. occur in to the atmosphere. The concentration of emission from a cell depends upon the type of cell, bath chemistry, scrubbing system and gas cleaning equipment used. These emissions cause severe environmental damages such as global warming and disease like fluorosis, cancer, asthma, emphysema, bronchitis etc. Through the development of newer technologies like, intro-duction of prebake technology, use of non-consumable (inert) anode, use of computer controlled and point feeding of alumina to the cell to control the frequency and duration of anode effects, use of low carbon pitch to replace tar, use of pollution monitoring and control equipment etc., there is a significant reduction in the emission levels. This paper deals with the factors infl-uencing the generation of these emissions and its reduction through the development of various cleaner technologies. Use of pollution control equipment and other remedial mea-sures to minimise the environmental pollution are also discussed

Speciation of Cu,Cd and Pb in coastal waters of Kandla-Porbander Shelf region, west coast of India

227-229Disserved, labile and non-labile concentrations of Cu,Cd and Pb in coastal waters of Kandla-Porbander Shelf region have been analysed. Labile form of these three elements are dominant over their non-labile form. While labile forms of ph and Cd are relatively enriched in surface due to anthropogenic inputs as well as terrestrial run-off, the sources of labile Cu is of marine origin

Characteristics and utilisation of copper slag - a review

Copper slag, which is produced during pyrometallurgical production of copper from copper ores contains materials like iron, alumina, calcium oxide, silica etc. For every tonne of metal production about 2.2 ton of slag is generated. Dumping or disposal of such huge quantities of slag cause environmental and space problems. During the past two decades attempts have been made by several investigators and copper producing units all over the world to explore the possible utilisation of copper slag. The favourable physico-mechanical characteristics of copper slag can be utilised to make the products like cement, fill, ballast, abrasive, aggregate, roofing granules, glass, tiles etc. apart from recovering the valuable metals by various extractive metallurgical routes. This paper gives a review of characteristics of copper slag as well as various processes such as pyro, hydro and combination of pyro-hydrometallurgical methods for metal recovery and preparation of value added products from copper slag. (C) 2003 Elsevier Science B.V. All rights reserved

Electrorefining electrolyte from copper plant dust

An attempt was made to develop a suitable process for the recovery of copper from the dust sample of copper plant by sulphuric acid leaching with the idea that the resulting leached copper sulphate solution Could be used directly as electrolyte in the copper electrorefining plant. XRD analysis of dust sample showed that copper was mainly present as sulphide and sulphate forms. Sulphuric acid leaching of the sample was carried out varying different parameters, The maximum copper recovery of 75% was achieved with the leaching parameters 353 K temperature. 4 h duration. 1:10 solid:liquid ratio and 10% H2SO4 concentration. Roasting followed by leaching experiments were also carried Out. It was found that leaching of the roasted (873 K) sample in sulphuric acid medium yielded maximum copper recovery of 95%, Leaching kinetics of roasted product indicated that mixed control i.e. ash diffusion and chemical control reaction was prevalent. XRD analysis of the roasted sample showed that copper sulphide was converted to oxide which probably increased the recovery of copper, It was also found that composition of the leach liquor obtained in optimised condition was comparable with the composition of electrolyte of operating electrorefining plant