Integrated smelters

In order to explore composition modulation of the final stage of a converter further, Briggs et al. (1978) added a second integral reactor, also holding about 30 g of the vanadia catalyst. With the preconverter in place, this system was operated on a typical feed from sulfur burning, with a S02 02 N2 composition in vol% of 10.8 15.2 74, and from a smelter effluent with a composition of 8.0 6.2 85.8. The cycled beds of vanadia catalyst were held in a fluidized sand bath at 401°C for the former feed and at 405°C for the latter one. The space velocity for both the air and the S03/S02 mixture was about 24 min 1 (STP). Table II summarizes the experimental results for the cycle periods tested. 

Some cokeless technologies in use or under development include the Japanese direct iron ore smelting (DIOS) process, in which molten iron is produced directly with coal and sinter feed ore, the HIsmelt process, where ore fines and coal are used to achieve a production rate of 8 t/h using ore directly in the smelter, and the Corex process, which has an integral coal desulfurizing step, making it amenable to a variety of coal types.14... 

Industrial furnaces are enclosed units that are integral parts of a manufacturing process and use thermal treatment to recover materials or energy from hazardous waste. These units may use hazardous waste as a fuel to heat raw materials to make a commodity (e.g., a cement kiln making cement) or the unit may recover materials from the actual hazardous waste (e.g., a lead smelter recovering lead values). The following 12 devices meet the definition of an industrial furnace12 ... 

The presence of chlorides from the PVC separators in the battery posed significant problems with the larger, integrated lead smelters who recovered other metals such as silver, copper, and zinc. Chlorides have serious implications for the recovery of these other elements. They reduce the life of the refractory lining of the furnace and affect the sinter quality. These difficulties have largely abated with the shift to polyethylene separators. 

The surveyed lead smelters comprise a total production of more than 1.5 million tonnes of lead in 1999. Operating data from the Herculaneum smelter of the Doe Rim Company, U.S.A. were also integrated into the survey. These data were extracted from the preceding survey as well as from the publication about the smelter elsewhere in this volume. This should be taken into account when analyzing the information. The technical discussion and drawn conclusions are based primarily on the results of the 2000 questionnaire. Altogether, this survey embraces approximately 1.75 million tonnes of produced lead, representing 86% of the total lead production of the primary smelters in the Western World in 1999. 

Regardless of the choice of the procedure for refining the lead bullion, the first stage is dressing. This operation is normally performed as the last step of the smelting process and is integrated in the smelter operation and not in the refinery. Here the bullion is simply cooled in order to precipitate mainly copper and nickel. 

The Kidd Metallurgical Division is an integrated metallurgical facility, located in Timmins, Ontario, Canada, which comprises a 10,000 t/d concentrator, a 145,000 t/y copper smelter and refinery, and a 150,000 t/y zinc plant. In addition to copper and zinc, the site produces 600 t/y of cadmium, 1200 t/y of lead contained in a lead/silver. residue, refined indium, and 100,000 kg/y of silver and 500 kg/y of gold, contained in anode slimes. Sulfur products produced are 580,000 t/y equivalent 100% H2SO4 and 28,000 t/y of liquid SO2. Total site complement as of March 2000 was 890 employees. 

The PLACID process could be perfectly integrated if it were employed in parallel with a pyrometallurgical smelter. In this way, any lead fumes, drosses and slags from Ae pyrometal-lurgical line can be passed to the leaching bath of the PLACID line and the cements from the purification stqi could be fed into the furnace. Important gains would be obtained fix)m the oiviromnental, process efficiency, product quality and economical points of view. 

Szerszen L, Chodak T, Karczewska A (1993) Areal, profile and time differentiation of heavy metal content in soils in the vicinity of copper smelters in LGOM, Poland. In Eijsackers, Hamers (eds) Integrated soil and sediment research. A basis for proper protection. Kluwer, Dordrecht, 279-281... 

As well as removing zinc, fuming will also remove most of the lead content of the slag and if this is recycled by return of zinc smelter residues to the lead smelting stage, then almost complete lead recovery can be achieved in an integrated operation. This ability of lead to fume is illustrated by the vapour pressure of lead compounds at 1250°C ... 

Canadian lead smelter workers, N =381 Measurement of PbB, serum Pb, PbBO, ALAD allele ALAD1 workers showed higher slope of PbBO to integrated PbB/time versus ALAD2 workers ALAD 1-2 or ALAD 2-2 had higher PbB Fleming etal. (1999)... 

Port Pirie, Australia, children (537) exposed from a Pb smelter McCarthy Scales (MSCA), 4 years old Integrated and year-specific PbB means by quartile Integrated PbB most strongly inversely associated with GCI scores McMichael etal. (1988)... 

A subset of the cohort (N = 332) was tested at 4 years of age using the McCarthy Scales. By this age, the smelter group mean PbB had risen to 40 pg/dl (rounding) versus controls mean of 10 pg/dl (rounding). GCI scores were statistically inversely associated with all postnatal exposure markers and with prenatal values > 20 pg/dl (Wasserman et al., 1994). At 7 years of age, children (A = 301) were tested using the Third Edition, Wechsler (WlSC-III) IQ scales and various exposure markers (Factor-Litvak et al., 1999). Adjusted for confoimders, there was a statistically significant inverse association of Performance IQ on the WISC-III tests with an integrated exposure measure, the lifetime Area-Under-the-Curve measurements, at 5—7 years. 

As an example of such an integrated approach, a case study is reported in which a soil from a former smelter and scrapyard was investigated. The case study demonstrates the importance of an investigative approach that employs a range of analytical techniques to evaluate toxic metal distribution and mobility. It showed that total element analyses of separated size fractions, characterization leaching tests such as sequential extractions, and detailed electron microscope analysis can provide complementary information on the location and chemistry of toxic metals in soils. 

The charge at the KSS plant in 1989, for instance, consisted of about 70 per cent low grade lead concentrate, 20 per cent zinc leaching residues and sundry oxides, and 10 per cent fluxes. This mix partly results from the plant s position within the Portovesme integrated lead-zinc complex. For a detailed description and discussion of the process see Perillo and Carlini, Performance of the KSS lead smelter in Portovesme, Italy , in Jaeck (ed) (1989) and Perillo and Ibba, Portovesme KSS lead plant increases production in ILZSG (1991). 

The degree of integration, both with raw material suppliers and fabrication plants, may also provide distinct advantages, as will increased product variety, especially where this allows increased value-added to be realised by the smelter. 

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