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By M. Manrique

Various pyrometallurgical methods for treating Ilmenite and Zircon concentrates are reviewed. Laboratory experiments, using a thermal plasma reactor, have been performed to evaluate: the conversion of ilmenite to TiC or TiC-Fe and the conversion of zircon to ZrC or ZrC-SiC. Results are examined and possible processing routes are identified.

Jan 1, 1996

By L Klemettinen, A Jokilaakso, D Attah-Kyei, P Taskinen, M Tiljander, D Sukhomlinov, D Lindberg

In this study, the use of carbon neutral biochars as reducing agents in the pyrometallurgical treatment of nickel slag was investigated at 1400°C in order to recover valuable elements such as copper and nickel from the slag. A large amount of slag is generated during the nickel matte smelting. Nickel slag contains valuable elements such as copper, nickel and cobalt, which can be recovered. Disposal of this slag results in loss of resources and may cause pollution of the environment. It is important to retrieve these metals for environmental and economic reasons. In this study, the slag was reacted with non-fossil reducing agents (biochar) which were produced from hydrolysis lignin and black pellet biomass pyrolyzed at 600 and 1200°C and with metallurgical coke for comparison. The reduction experiments were done at 1400°C for 15, 30 and 60 mins under inert gas atmosphere. The samples were quickly quenched and analysed with Electron Probe X-ray Microanalysis (EPMA). The results showed that the use of biochar resulted in faster reaction kinetics in the reduction process compared to coke. The fast reaction kinetics is attributed to the relatively high content of volatiles in this biochar, leading to gas formation and thus mixing of the sample material. Moreover, thermodynamic modelling was also performed using FactSage™ to simulate equilibria with different amounts of biochar. The metal to slag distribution coefficient calculated from the results of thermodynamic modelling were consistent with experimental results. In addition, thermodynamic calculations confirmed that nickel is reduced rapidly and it deports to the metal alloy phase. As the reduction progresses or extra reductant is available for reactions, more iron is deported to the metal phase. The calculations also revealed that Zn vaporises into the gas phase.

Jun 19, 2024

By J Herbertson

æZero waste steel making productionÆ has already been the subject of several studies and also the successful result of some companies. Regarding waste and by-products, slags are the largest in terms of weight, although among the least hazardous. All steelmakers around the world are presently looking into profitable solutions, according to their local conditions: environment constraints, available markets, and mode of operation. Today the major technical methods of slag value capture include different levels of magnetic separation and screening to remove entrained steel, for production of aggregate in civil works. A survey of different retrieval processes shows that pyrometallurgical processing of steelmaking slags will increase the recovery ratio of iron and other metals. In the process, the remaining part of the material, a mixture of metallic oxides, can be easily transformed into hydraulic binder such as cement. Can steelmakers consider the slag as a co-product, and not only a waste or by-product? The ability of pyrometallurgical processes to treat other wastes and by-products generated in the steelplant is an opportunity for the steelmakers to reach the æzero waste productionÆ status. A technical survey of the experiences and possible solutions of pyrometallurgical processing is presented as well as technical descriptions of technological, economical and profitability analysis in relation with foreseeable markets.

Jan 1, 2002

By Seishiro Hirakawa, Hiroshi Tokunaga, Hironori Nakamura

Two unique processes of reclaiming zinc from various secondary materials were developed and have successfully been operated for years by Mitsui Mining and Smelting Co. These processes were established based on the characteristic and local energy conditions; i.e., (1) at Miike Smelter, located above the largest coal deposit in Japan, a combination of slag fuming and semi-blast furnace (MF)processes takes advantage of using coal and the carbon bearing briquette residue from the vertical retort plant as reducing agents, (2) on the other hand, at Kamioka Smelter, a direct reduction of zinc-bearing lead slag by using electric furnaces is of advantage in view of cheap electric power supply from our own hydraulic power plants. The former also consumes lots of zinc bearing fines and drosses from various steel plants, fabricators and secondary zinc smelters, while the latter, zinc leach residue from its own electrolytic plant

Jan 1, 1976

AGGLOMERATION U.S. 4,067,727 - In the sintering of a charge of iron oxide ore, a fuel and a flux on a travelling grate machine, the dust problem is minimized by providing a plurality of cooling zones and by directing heated dust-laden air from a first cooling zone to the sintering zone wherein the dust is filtered from the air by the material being sintered. Air from a further cooling zone can be exhausted directly to the atmosphere. Dust removal in the cooling zone is improved by using a purging zone in which higher pressure air agitates the dust in the sintered material. This patent is a division of U.S. Patent No. 3,973,762, dated Aug. 10, 1976. F. Cappel, assigned to Dravo Corp. Jan. 10, 1978. 6 pp. (75-5). Filed: 4-1-76 (672,748).

Jan 1, 1979

By T. R. A. Davey, J. W. Sherman, B. J. DiSanto, G. Bjorling, G. S. Stacey, J. T. Cullom, R. L. Bird, S. E. Woods, J. C. Blair, Jorma Honkasalo

Most pyrometallurgical processes take place at high temperature with rapid chemical reactions when the elements and compounds are usually liquid or gaseous. Smelting. The classical method of obtaining a metal from its ore or concentrate is to smelt it in a furnace. The initial letter "s" of this word implies that, in addition to the physical process of melting, a chemical change also occurs. This is usually the reduction of metal oxide to metal by carbon or through a series of processes involving oxidation and reduction. Since solid-solid contact would not be sufficient to give a high rate of reaction, most smelting reactions occur by medium of two reactions involving solid-gaseous contact: where M represents a metal. The commonly preferred unit for carrying out these reactions is the blast furnace,1 which is a vertical shaft of refractory brick or water-cooled steel in which lumps of metal oxide and coke are fed at the top, and an air-blast is injected through tuyeres (water-cooled pipes) in the bottom. Molten metal is withdrawn from a pool at the bottom of the furnace, while N2, CO, and CO2 gases leave the top of the furnace, carrying some fine dust or fume with them, which

Jan 1, 1985

US 4,134,944-Production of iron oxide ore pellets of uniform size and excellent strength. Small pieces of ore are rolled into nuclei in a first pellet-rolling circuit in the presence of a binder, the nuclei sized and hardened by sintering or cold-bonding of the binder, the nuclei rolled in additional ore to form product pellets, the pellets sized, the suitable size fraction taken as product, and undersize pellets returned to the rolling operation. P. A. Ilmoni and R. Drugge, assigned to Luossavaara-Kiirunavaara AB Jan 16, 1979. 5 pp. (264-37) Filed- 5-25-77 (800,278) Priority: Sweden, 6-2-76 (76/06,¬241). Same British 1,553,763, dated Oct 10, 1979. US 4,145,210-In the induration of pellets of iron oxide ore or iron works dust or sludge, a charge of dried pellets and 2-20% by weight of coke having a size range of from 5 to 30 mm, a drum index of more than 70, a reactivity index of less than 50, and a tumbler index of more than 50 is charged into a rotary kiln The charge is heated and passed through the rotating kiln to indurate the dried pellets without burning the coke Powder-coated coke is recovered from the kiln for reuse. Ring formation in the kiln is substantially prevented. K. Kato and K Kadota, assigned to Sumitomo Metal Industries, Ltd, and Sumitomo Heavy Industries, Ltd. Mar 20, 1979 10 pp (75-3) Filed- 2-22-77 (770,947) Priority: Japan, 2-24-76 (51/19,754) US 4,145,211-Method of cooling hot metallized iron oxide ore agglomerates from a direct reduction furnace Agglomer¬ates ranging from 3/a in to 41/2 in in cross-section and at a temperature of 1000-2000°F are formed into a moving bed while at rest relative to each other Air at ambient tempera¬ture is passed through the bed at a velocity sufficient to cool the agglomerates rapidly to a temperature no greater than about 500°F without substantial reoxidation of the metal in the agglomerates and by using air as the sole cooling gas. C A Czako, A Berzins, and M J Greaves, assigned to Arthur G McKee & Co Mar. 20, 1979 15 pp. (75-34) Filed: 7-18-77 (816,467)

Jan 1, 1980

US 4,194,729 - Sintering of iron oxide ore on a straight sinter belt. The upper strand of the belt is divided into sintering and cooling sections with windboxes for removing their respective gases. The main for collecting cooling gas is located beneath the lower strand and is connected to opposite sides of the windboxes, while the main for collecting sinter exhaust gas is located beneath the lower strand and connected to sinter section windboxes. Both mains are exhausted via gas-evacuating fans and pipes to a flue. Space requirements are lessened and plant accessibility can be maintained at optimum conditions. K. Wacker and F. Feigk, assigned to Dravo Corp. Mar. 25, 1980. 8 pp. (266-144). Filed: 10-30-78 (956,058). Priority: West Germany, 12-16-77 (2,756,082).

Jan 1, 1982

US 4,183,899 - Flow process for chlorinating ilmenite. A laminar flow of a mixture of ore, a carbonaceous reductant, and chlorine gas or other chlorinating agent is passed through a reaction zone maintained at a temperature of 1350 to 1950°C and a product stream Including titanium tetrachloride is withdrawn from the zone. The atomic ratio of carbon to oxygen in the feed mixture is greater than 1:1, and the molar ratio of chlorine to titanium solids In the product stream is between about 0 5.1 and 2:l. Titanium chlorides and metallic iron are recovered separately from the product stream. J.P. Bonsack, assigned to SCM Corp, Jan. 15, 1980 21 pp. (423-79). Filed. 3-10-78 (885,442).

Jan 1, 1982

US 4,194,902 - Pig iron or other molten lion is effectlvely desulfurized by treatment with a mixture preferably about 60% by weight commercial grade calcium carbide, 30% dried limestone diamide, and the remainder bituminous coal. Equivalent desulfurization is obtained using a significantly lesser amount of desulfurizer than in previous mixture of calcium carbide and limestone diamide W Gmohling, assigned to SKW Trostberg AG. Mar 25, 1980. 3 pp. (75-55) Filed: 9-12-78 (941,659) Priority. West Germany, 9-15-77 (2,741,588). Same. British 2,008,153, dated May 31, 1979.

Jan 1, 1982

US 4,185,996 -- Removal of arsenic and sulfur Impurities from arsenic-containing cobalt sulfide ore. The ore is oxidized In air at a temperature of 700 to 800°C for 3 to 8 hr to drive off the bulk of the sulfur The oxidized ore 1s heated with a reducing gas at a temperature of 700 to 800°C for 2 to 6 hr to volatilize arsenic, and the final calcine 1s leached with an acid to eliminate substantially all of the remaining arsenic. A.R. Zambrano, assigned to Hanna Mining Co Jan. 29, 1980. 3 pp. (75-2). Filed. 2-13-78 (877,002).

Jan 1, 1982

US 4,181,520 - Direct reduction of iron oxide ore to sponge iron in a rotary kiln. Ore is fed into the kiln along with coal briquettes and passed through a preheating zone and then a reducing zone countercurrent to the flow of a kiln atmosphere which includes air or other oxygen-containing gas. The agglomerated coal is heated at such a rate that it disintegrates into fine particles in the preheating zone. The coal is largely recovered for reuse, while reduction is effected with a reducing flame rather than the coal. G. Reuter and W. Schnabel, assigned to Metallgesellschaft AG. Jan. 1, 1980. 6 pp. (75-36). Filed- 10-19-78 (952,870). Priority: West Germany, 1-14-75 (2,501,182). Same: British 1,532,969, dated Nov 22, 1978.

Jan 1, 1982

US 4,190,434 - In the thermal production of magnesium metal, a mixture of calcined dolomite, an iron- silicon-aluminum alloy as a reductant, and residual slag from the production of ferrochromium is smelted to evolve magnesium vapor, which is then condensed. The use of bauxite is lessened or eliminated because of the relatively high alumina content of the residual slag. R. Bonfils, A. Mena, C. Payn, and L. Septier, assigned to Ste. Francaise d’Electrometallurgie (SOFREM). Feb. 26, 1980. 6 pp. (75-10R). Filed: 6-14-78 (915,387). Priority: France, 6-24-77 (77/20,227).

Jan 1, 1982

By T. R. Curr, R. T. Jones

Keywords: Pyrometallurgy, Mintek, DC arc furnace, plasma, smelting, chromite, ilmenite, cobalt, slag, zinc fuming, dust, magnesium, laterite, ferronickel, arc modelling, Pyrosim, thermodynamics The Pyrometallurgy discipline at Mintek was initiated in the early 1970s, to support a growing ferroalloy industry in South Africa. In addition to a range of pyrometallurgical options, Mintek specialises in DC arc furnace technology and has pilot plant facilities up to 5.6 MVA, as well as a strong base in process and arc modelling. Industrial processes have been developed for ferrochromium production, ilmenite smelting, and cobalt recovery from slag. Recent work has been done on such processes as the production of ferronickel from laterite ores, the fuming and condensation of magnesium, and the recovery of platinum group metals from 'difficult' feedstocks.

Jan 1, 2006

By U. M. J. Boin, E. V. Verhoef

Pyrometallurgical reactors constitute a key processing component in the total primary and industrial/recycling resource cycle, being involved both in primary smelting, converting and extraction, as well as the reprocessing of scrap, from aluminium cans to end-of-life automobiles. Therefore the pyrometallurgical reactor?s role in achieving sustainability is the central theme discussed in this paper since optimising their operation minimises waste, residue and offgas (NOx, dioxin, CO2) and maximises product quality and therefore efficiency. To effectively control the overall resource cycle, one needs to take a systems modelling approach of the whole cycle, seeking to also understand the dynamic process behaviour of the individual components of the cycle, and then especially the part that contributes most to the chemical conversion, namely the pyrometallurgical reactor. This paper highlights the role of pyrometallurgical thermodynamics in the whole resource cycle and specifically places equilibrium thermochemistry in the context of process dynamics where large, variable inventories are recycled or maintained within the system. This paper will therefore review the semi-empirical dynamic modelling tools, which are used to model complex systems with the specific goal of developing dynamic predictive models, which also include slag-alloy chemistry, towards controlling the recycling in a feed forward manner. To illustrate the primary production of metals, high carbon ferrochrome and Ni-Cu-matte smelting will be presented as a brief case study. Also fundamental studies in blast furnace and waste incineration kilns will be given. It also will show how the distributed nature of the chemistry of melts in the case of primary extraction, and industrial (recycling) materials such as recycled end-of-life vehicles, have a significant impact on the process outcomes and model predictions. It is therefore argued that the fundamental thermodynamics and kinetics in metallurgical reactors play a final crucial role in modelling the closed material cycle, but only when it is used in conjunction with process systems theory based on reconciled data for parameter estimation and model calibration. System models for aluminium and car recycling will be given as well as a dynamical system model that describes the interconnected material flows for Ag, Au, Bi, Cu, Fe, Ni, Pb, PGM, Sn and Zn for a study on lead-free solder.

Jan 1, 2003

By Norman E. Lehman

INTRODUCTION The Washington Camp - Duquesne mining district is located on the east flank of the Patagonia Mountains, 98 kilometers south of Tucson and within 5 kilometers of the International border (Figure 1). Since the development of high-grade silver and copper ores by settlers in 1862, the Washington Camp - Duquesne district has yielded an estimated 450,000 metric tons of ore. The mined ores averaged 8% zinc, 2% copper, 3% lead and 124 grams of silver. REGIONAL GEOLOGY The Patagonia batholith, of Laramide age, crops out in the core of the Patagonia Mountains intruding Precambrian granite, Paleozoic sediments and Mesozoic igneous, volcanic and clastic rocks. This granodioritic batholith lies in a northwest-trending zone of Laramide plutonic rocks, which can be traced for a distance of 320 kilometers from the Nacozari district in Sonora, Mexico to the Silver Bell Mountains west of Tucson, Arizona. Several major porphyry copper systems occur within this plutonic belt including the Red Mountain deposit found at the northern end of the Patagonia Mountains. Data from more than 80 mineral deposits within the Patagonia Mountains show metal zoning symmetrical to the Patagonia granodiorite (Graybeal, 1975). Disseminated copper-molybdenum deposits occur within the batholith. Pyrometa-somatic, limestone replacement and vein deposits of copper, lead, zinc and silver occur in the wallrocks adjacent to the. granodiorite and epithermal manganese-silver deposits occur at the outer periphery of economic mineralization. GEOLOGY OF THE WASHINGTON CAMP - DUQUESNE DISTRICT Stratigraphy Nearly 900 meters of miogeosynclinal Permian and Pennsylvanian sediments are exposed in the district (Figure 2). In addition, 700 meters of older Paleozoic rocks crop out 6 kilometers north of the district. The Paleozoic rocks occur in fault contact with a sequence of Triassic-Jurassic pyroclastic and flow rocks, ranging in composition from latite to rhyolite.

Jan 1, 1977

By Norman E. Lehman

Pyrometasomalic mineralization occurs within meta-morphosed Paleozoic carbonates intruded by Laramide granodiorites. Two types of alteration developed shams in the district. The dominant type is post-magmatic which developed an early hydrous endoskarn phase, and intermediate anhydrous exoskarn phase, and a late hydrous phase affecting both sham types. A rare, second type is magmatic in age, lacks the hydrous phases, and developed a mineralogically-zoned endoskarn. Garnet exoskarns lacking associated plutonic rocks are stratigraphically controlled and contain an early anhydrous phase, an intermediate hydroxyl-bearing phase, and a late hydrous phase associated with base metal deposition.

Jan 1, 1981

By R. W. Newcomb

THE constancy of calibration, and to a great extent the life, of a thermoelement is dependent on the suitability of the primary protecting tube in which the wires are mounted, particularly when used at high temperatures. An ideal thermocouple protecting tube would be com-posed of materials that would not contaminate the thermoelement wires contained in it-one that would remain absolutely gas-tight ,it all temperatures of usage, that will not be attacked by gases, or other surrounding agencies, that is not destroyed by heat, that withstands sudden and extreme temperature changes, that affords a high degree of mechanical protection and does not deform at high temperatures, that is a good heat conductor and obtainable in small diameters so as to keep down lag factors. It has not yet been possible to produce tubes of any known mate-rials that will meet all of these conditions. In selecting protecting tubes, therefore, one should be chosen the characteristics of which best fit it to the particular conditions of usage. Frequently conditions are such that two tubes have to be used, a primary gas-tight protecting tube inside of a secondary protecting tube, because certain agencies will attack the primary gas-tight tube unless it is guarded by the outside tube.

Jan 9, 1919

A. 0. ASHMAN, Palmerton, Pa. (written discussion *.).-Mr. Newcomb's paper has interested me greatly, as I have had numerous experiences along this line. I do not think enough emphasis can be put on his warn-ing to keep platinum couples free from contact with quartz tubes, as silica shows a tendency to alloy with platinum to a surprising degree even at low temperatures. I have frequently had evidence of silica contamination in a perfectly good tube, in which there was seemingly no possibility of a reducing atmosphere. This is rather important as it seems to be common practice to insulate, as well as protect, the wires by means of- capillary silica tubing, thus allowing the entire wire to be in contact with the silica. The best way to mount a couple in a silica protecting tube is by means of double-bore porcelain insulating tubes, the protecting tube being slightly longer than the couple so as to leave a space between the couple and the end of the tube. In this way there is no possibility of contamination from silica. In no case should silica capillary tubes be used to insulate platinum wires. Mr. Newcomb states that there is still much to be desired in pyro-meter protecting tubes; this is in keeping with my experience. From a practical standpoint there is not a satisfactory pyrometer tube on the market for high temperatures; with all clue respect to the many improve-ments and good work recently done in this line. I believe that the whole future development of pyrometry is dependent on the development of suitable refractories. With suitable refractories, for example, Darling's1 work with liquid couples could be developed to a practical basis, making possible the use of base-metal couples to replace platinum.

Jan 12, 1919

By F. A. Harvey

DURING the last few years, there has been a constant tendency toward increasingly high temperatures in many lines of industry. The necessity for increased production of coke gave a 16-hr. coking period where we used to have 24 or even 30-hr. periods. Mechanical stokers have increased the temperatures in boiler furnaces. The use of a chain-grate stoker with coke-breeze fuel necessitates a low arch in the furnace and temperatures run much higher than firebrick were formerly called upon to stand. These higher temperatures have necessitated more rigid tests and the separation of even high-grade firebrick into separate classes. More severe tests mean higher temperatures and closer control, and this, in turn, means better pyrometer tubes. Platinum couples do not have a very long life when used at temperatures exceeding, say, 1200° C., but the proper selection of a high-grade brick to be used in a-boiler setting will save the cost of several couples; and with freight rates continually increasing it becomes increasingly important to know where brick may be bought, nearest the job, that will prove satisfactory. Couples that will stand continuous use at higher temperatures, of tungsten, molybdenum, or other metal, will doubtless be forthcoming as soon as the need becomes sufficiently urgent. There are on the market several tubes that are entirely satisfactory for temperatures up to 1300° C., if properly protected from heat shock. The Semet-Solvay Co. makes a practice, however, of testing silica and clay firebricks at 1450° C. for 72 hr., and so far we have been unable to find a tube that- is entirely satisfactory for this purpose. A graphic record of the temperature during the entire test is extremely desirable and hence we have been trying out anything that gave promise of success. Several years ago we were using insulating tubes, made purely for electrical work, of vitrified porcelain. These tubes stood up under any temperature we were able to reach and were apparently impervious to gases. When this stock gave out, due to mechanical breakage, we tried other insulation tubes only to have them melt down like glass. Marquardt Masse tubes were tried next under a statement from the distributors

Jan 9, 1919