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By R. G. L. McCready, R. O. van Everdingen, M. Kalin, R. van Everdingen

"This paper is based on data generated between October, 1986 and October, 1989, during the implementation of an Ecological Engineering close-out for a zinc mine in Northern Ontario, where 690000 tonnes of tailings contain 41.1% pyrite and 4.1% pyrrhotite. The objective was to determine rates of sulphide oxidation and iron precipitation in the tailings. Those rates are relevant for the assessment of the long-term effectiveness of biological systems employed in the removal of heavy metals from contaminated drainage issuing from tailings.Data were collected on the topography and stratigraphy of the tailings basin, subsurface temperatures and groundwater levels, and chemical analyses were made of water samples collected from a number of piezometers. The thickness of unsaturated tailings varied widely between individual piezometer locations; annual maxima ranged from 0.67 m to 3.55 m, and annual minima from 0 to 2.68 m. Sulphate concentrations ranged from 36 mg/L to 20180 mg/L; iron concentrations from 0.36 mg/L to 9938 mg/L; and zinc concentrations from 0.33 mg/L to 1123 mg/L.The geochemistry of the piezometer samples suggests that some of the initial Fe content, resulting from metal sulphide oxidation, is subsequently precipitated in the tailings pile and, possibly, in the underlying unconsolidated sediments, probably in the form of iron-hydroxide and Na-jarosite. Other metals such as Zn may be co-precipitated with Fe. The discharge of a portion of these metals to the environment would be delayed by this process. Some of the initial sulphate may also be lost from solution, probably by precipitation of gypsum; approximate saturation degrees for gypsum ranged from -3.27 to +0.47. The precipitated minerals will somewhat decrease the porosity and permeability of the tailings.Sulphide-oxidation rates, calculated using the analytical results and the estimated amount of annual recharge at the tailings site, average 0.0057 mol/kg/yr. Calculated iron-precipitation rates average 0.000386 mol/kg/yr. It is concluded that the characteristics of seepage from mining wastes may change with time, reflecting the solubilization of precipitated secondary minerals."

Jan 1, 1992

By J. B. Griffiths

Clearly there is a tremendous need for assistance in Eastern Europe since most industries must undergo major restructuring. The new governments face many dilemmas, the first task being to establish an order of priorities to deal with the numerous problems at hand. Issues such as the standard of living take low priority compared with market economy and ecological problems. The concept of a Comecon market is now virtually non-existent and trade in roubles ceased from 1991. From this time onwards countries were obliged to trade using free market prices. Governments must also avoid the economic mistakes of countries such as Poland with its high devaluation and lack of economic control and, if possible, contain inflation and unemployment. The privatization of Eastern European enterprises raises considerable difficulties, particularly for large corporations, employing anywhere from 50-100,000 people, which played a major role in the national economy. Whichever method is selected, however, still has to overcome the problem of lack of capital and evaluating the national property. For example, earnings represent only a small percentage of the value of these national industries and thus cannot convert to private ownership without foreign capital investment, either direct or as joint venture capital.

Jan 1, 1992

By E. P. Wiechmann, J. A. Henríquez, P. E. Aqueveque, L. G. Muñoz, G. A. Vidal

"The original segmented intercell Optibar succeeded in reducing the magnitude and occurrence of short circuits. It also improved the specific energy consumption of the process. This paper expands the load current source concept introducing a triple segmented bar. This new bar adds immunity to dirt contacts and open circuits. Moreover, it further improves the standard deviation of current densities. As compared with industrial practices this development should accomplish an 8% specific energy reduction. Also, a plant implemented with BBS should be able to work with 12.5% higher process currents than Walker without compromising the operation.INTRODUCTIONIn 2011 the technology based on current mode was implemented at industrial scale. The success of this technology moved CIM Magazine (Lanktree, 2011) to write in the Jan 2012 issue an upfront story of this technological innovation. To cover the story, the technical reporter Graham Langtree was appointed by Peter Braul Editor of the upfront section. The article tells that “More than 40,000 tonnes of copper have been refined in a year-long test run of Optibar Inc.’s new technology at Barrick Gold’s Zaldívar copper plant in northern Chile. The new segmented intercell bars being used in the Compañía Minera Zaldívar refinery have slashed energy costs, reduced short circuits during refining and allowed the production of heftier, purer sheets of copper – gains that all promise to boost the plant’s margins. A copper refining tank house containing the cell circuits typically consumes 2,000 kWh of electricity to produce a single tonne of grade-A copper. Yet, monitoring the energy efficiency of the Optibar technology after increasing the weight of harvested copper sheets, the project’s engineers recorded a 92 kWh-per-tonne cut in energy consumption, a savings of 4.6 per cent. “Today, with the power prices we have, Optibar technology represents a potential savings for the whole plant of US$1.5 million per year,” says Robert Mayne- Nicholls, executive general manager of Barrick Gold’s Chilean operations.”"

Jan 1, 2012

By I. Moreno-Ventas, G. Ríos, J. C. Fernández-Caliani, M. Bacedoni

"This paper delves into the constraints on the nature, origin and thermal evolution of the accretions formed in the uptake shaft of the flash smelting furnace operated by Atlantic Copper in Huelva, Spain, outlining recommended practices for preventing accretion buildup. The accretions were investigated using quantitative electron probe microanalysis, X-ray diffraction and digital imaging techniques, and the experimental data on mineral composition, crystal chemistry and textural relationships were interpreted in terms of thermodynamic phase equilibrium in the SiO2-Fe-O-S system. The results suggest that two distinct types of accretions were formed by the fractional crystallization of two coexisting immiscible melts, under changing conditions of oxygen partial pressure (pO2). The type I accretion of magnetite + delafossite ± cuprite ± tridymite ± metallic copper crystallized from a fractionating copper-rich melt at pO2 above about 10-5 atm, while the type II accretion of magnetite + fayalite + metallic copper + chalcocite derived from a melt with lower copper concentration when pO2 levels dropped below that critical level. Phase compositions and textures were consistent with a cooling history of both compositionally contrasting liquids from about 1,250 °C, the liquidus temperature of magnetite, to eutectic or near-eutectic temperatures of around 1,100 °C. The maintenance of appropriate temperatures — above the liquidus temperature of magnetite — and oxygen partial pressure levels may be critical for the prevention of accretion buildup. IntroductionCopper flash smelting with oxygen-enriched air, an autothermal process developed half a century ago by Outotec (Espoo, Finland), formerly Outokumpu, currently accounts for about 50 percent of the world’s primary sulfide-based copper (Schlesinger et al., 2011). The partial reaction of copper sulfide concentrates produces two separate molten streams, copper-iron-sulfide matte and iron oxide-rich slag, and releases sulfur dioxide (SO2) gas. The matte is sent to converters to remove the remaining iron and sulfur, leaving blister copper with grade of about 99.5 percent copper (Cu), which is cast into anodes for electrolytic refining.The SO2-rich gas generated by the oxidation of sulfide feed particles contains a significant proportion of dust that is entrained in the process off-gas. The gas from smelting is transferred into a waste heat recovery boiler, where it is cleared of dust and cooled before it is converted into sulfuric acid. If the process is not operated properly, the dust-bearing gas may form accretions between the uptake shaft of the flash smelting furnace and the waste heat recovery boiler, causing severe problems in the gas handling system (Swinbourne, Simak and Yazawa, 2002; Miettinen, 2008; Stefanova et al., 2012). Removing the dust accretions usually requires a greal deal of time, effort and resources. Understanding the buildup of accretion may help in reducing the problems and optimizing the process"

Jan 1, 2017

By J. J. McDougall

Until quite recently, the coal in the Cape Breton field was won from comparatively thick seams with light cover, and from submarine areas, and the system of mining naturally followed was pillar-and-stall. This sytem permitted of cheap extraction, and enabled production from localities where other methods could not be employed to good advantage. Thus the pillar-and-stall system, applied to conditions as stated, justified its adoption. Our working seams today, however, are practically all under heavy cover, or are moving in that direction, and with this gradual increase in cover came the increased cost of roadway maintenance. At Princess colliery, the system of pillar-and-stall was followed until roof and bottom conditions became such that further operations were unprofitable, and the longwall method was then adopted as an economic necessity. This fact should be borne in mind when operating costs of both systems are being compared. The longwall method is not held as a cure for all difficulties of heavy cover, but through it these difficulties can be overcome with less expense than by pillar-and-stall. The longwall system of mining, strictly speaking, is one by which a seam of coal is totally extracted in one operation. There are, however, many modifications of longwall, and in some cases it is difficult to determine whether certain practices should be classed as longwall or pillar-and-stall, or a combination of both.

Jan 1, 1928

By Malte J. M. Gurgel, Axel Preusse

Recent three-dimensional surveying techniques have opened up new opportunities for the registration and monitoring of underground cavities. There are essentially two main methods available: Laser scanning, which is used both above surface and increasingly underground, and photogrammetry, which is also experiencing a renaissance with techniques like structure from motion through the algorithm-based orientation of high-resolution images. Both methods provide the capability to reconstruct reality by various 3-D products like points clouds and meshed models. However, they differ significantly in the steps of registration and calculation as well as in the resulting evaluation options.

By A Woodley, N C. Kunz

A mine site water balance is important for communicating information to interested stakeholders, for reporting on water performance and for anticipating and mitigating water-related risks through water use/demand forecasting. Gaining accuracy over the water balance is therefore crucial for sites to achieve best practice water management and to maintain their social license to operate. For sites that are located in high rainfall environments the water received to storage dams through run-off can represent a large proportion of the overall inputs to site; inaccuracies in these flows can therefore lead to inaccuracies in the overall site water balance.Hydrological models that estimate run-off flows are often incorporated into simulation models used for water use/demand forecasting. The Australian Water Balance Model (AWBM) is one example that has been widely applied in the Australian context. However, the calibration of AWBM in a mining context can be challenging. Through a detailed case study, we outline an approach that was used to calibrate and validate AWBM at a mine site. Commencing with a data set of monitored dam levels, a mass balance approach was used to generate an observed run-off sequence. By incorporating a portion of this observed data set into the calibration routine, we achieved a closer fit between the observed versus simulated data set compared with the base case. We conclude by highlighting opportunities for future research to improve the calibration fit through improving the quality of the input data set. This will ultimately lead to better models for run-off prediction and thereby improve the accuracy of mine site water balances.CITATION:Kunz, N C and Woodley, A, 2013. Improving the accuracy of mine site water balances through improved estimation of run-off volumes, in Proceedings Water in Mining 2013 , pp 267-272 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By Francis Foley

IN THE first report1 disks of steel of- known composition and history were exposed, under carefully prescribed conditions, to impacts of explosion products resulting from the explosion of 50-gm. charges of explosives having well-determined rates of detonation, or to, impacts of a weight of known mass, falling through measured distances. There were available at the Bureau of Mines Experiment Station five explosives, having rates of detonation of 5716, 4470, 3190, 2296, and 1523 meters per second. It being desired to continue this exposure downward, and no explosives with a lesser rate of detonation being at hand, resort was had to the impact of a falling weight, the differences in the velocity of impact being attained by varying the height from which the weight was allowed to fall. It was expected by this means to demonstrate experimentally that the development of Neumann bands was determined by the suddenness of the deformation of the metal in which they were produced. But while progressive deformations were obtained with the explosive charges, the falling-weight method failed because the tup was progressively deformed, also the disks were so flattened as to be unfit for metallographic examination. A return, therefore, has been made to the use of explosives as the source of energy, an air-gap being interposed between the charge of explosive and the disk, as the effect diminishes as the function of the distance between the charge and the object on which the products of its explosion, or the shock wave from its detonation, impinge. The details of the arrangement of the tests by the air-gap method were the same as those described by Foley and Howell,2 except that after the system had been set up and the desired apparent specific gravity for the explosive

Jan 2, 1926

Early in 1936 the Interstate Oil Compact Commission and other groups interested in forecasts of demand for petroleum requested the Bureau of Mines to make a physical inventory of crude-oil stocks in the United States. Accordingly, the 74th Congress -appropriated funds for conducting such a survey during the fiscal year ended June 30, 1937. In the discussions end hearings2/ relative to the need for the survey, the opinion was expressed that crude oil held is storage for long periods had lost so much of its gasoline content that the economic significance of total stocks should be discounted materially. Therefore, a primary objective of the survey was to

Jan 1, 1938

By J A. Wells, K G. Thomas, R F. Dewhirst

"One of the contributing factors to the extreme cost escalation in the first decade of the 21st century was the increase in the amount and cost of engineering work that went into studies and projects. Various reasons for this were identified, including unsatisfactory productivity due to a shortage of experienced/qualified engineers, the increased complexity and infrastructure requirements of many projects due to location, metallurgy that is more challenging and increasing environmental and social requirements. These conditions often led to unsatisfactory project results in terms of cost and schedule blowouts and created a loss of confidence – both internally and externally – in the industry’s ability to complete projects on time and on budget.Technical fundamentals aside, the experience and effectiveness of project teams has had, and continues to have, a major impact on project cost, schedule and ramp-up to nameplate capacity and operating parameters. There are unfortunately too many examples of where project teams have not been as effective as they could or should have been, all to the ultimate detriment of the project.Using the authors’ extensive experience on both owner’s and engineer’s teams, this paper discusses some of the main reasons for suboptimal team, and hence project, performance and offers thoughts on how best to build and maintain project teams. The analysis and conclusions drawn are built around the Tuckman model of group development known as ‘forming-storming-norming-performing’, which was first proposed some 50 years ago. Given the importance of good teamwork to project success, understanding how project teams grow and become efficient and productive is an essential part of good project management that should receive more attention.CITATION:Dewhirst, R F, Thomas, K G and Wells, J A, 2016. Building and maintaining effective project teams, in Proceedings Project Evaluation 2016, pp 38–48 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By A. R. Kirchner

This paper describing the practice at the concentrator of the Minas de Matahambre, S. A., is one of a series being; prepared by the Bureau f Mines on milling methods and costs. The Minas de Matahambre, S. A., concentrator treats the production of the Matahambre mine and has a capacity of 1,300 tons of copper ore per day by selective flotation. During the year 1930 the heads averaged 4.55 per cent copper, the concentrates 29.20 per cent copper and the recovery was 95.96 per cent.

Jan 1, 1931

By H. W. Wainwright

.1. The purification pilot plant and the equipment, solution, and gas cycle used for removing hydrogen sulfide and carbon dioxide are described. 2. As sulfur recovery is necessary in any large Fischer-Tropsch plant, pilot-plant runs were made at 300 p.s.i.g. to study the efficiency of tri-ethanolamine solutions in removing selectively hydrogen sulfide from gases containing varying amounts of carbon dioxide. 3. Aqueous solutions of TEA of 20, 30; 35, and 50 percent were investi¬gated. Data indicate that 30 to 35 percent is the optimum concentration if both selectivity and economy are considered. Slightly better selectivity is obtained with the.20 percent solution, but steam consumption is greater owing to the higher solution rates. Results from our pilot plant runs indicate that a 50 percent solution not only produces an acid gas of lower hydrogen sulfide content but also requires high solution rates to effect hydrogen sulfide purification. 4. Data from 37 runs using TEA are presented in tabular form. In addition, the data are correlated and presented in three sets of curves. By using these curves, it is possible to calculate the compositions of the purified and acid gases for various raw gas mixtures. 5. In cooperation with the Southern Natural Gas Co., investigations were carried out at 300 p.s.i.g. on the simultaneous removal of hydrogen sulfide and carbon dioxide, from gases using various concentrations of diethanolamine. 6. Data from 17 runs employing 20, 30, and 40 percent DEA are reported in both tabular and graphic form. 7. A comparison of the data from one DEA run made at 200 p.s.i.g. with those from the runs operating at 30O p.s.i.g. shows float the absorption capacity of the solution, and, hence, the steam requirements per gallon are about the sage for both pressures. .The only real advantage of the higher pressure is the additional volume of gas that can be treated. 8. The quantity of steam needed to reactivate fouled TEA and DEA solutions increased as the reactivator pressure was increased about 1,0 to 1.1 pounds of steam was required for each gallon of circulating solution when the reactivator was operated at 5 p.s.i.g. 9. A curve is included that shows the effect of the hydrogen sulfide con-centration in a lean 35 percent TEA solution on the hydrogen sulfide content of the purified gas and on steam consumption for reactivation. 10. Both TEA and DEA reduced the organic sulfur content of the raw synthesis gas considerably. Analyses of the lean amine solutions showed a gradual build up of sulfur compounds, indicating that the compounds formed by the amines and organic sulfur do not break down under the ordinary operating conditions of the reactivator. 11. Considerable operating difficulty was encountered in the pilot plant owing to foaming of the amine solutions. Laboratory experiments in which the effectiveness of certain antifoam agents was studied showed Alkaterge C to be most promising for the particular conditions studied.

Jan 1, 1952

By R. J. Kuczynski

The U.S. Bureau of Mines Reno Research Center investigated, developed, and patented a high-temperature cyanide leaching process for recovering platinum-group metals (PGM) from automobile catalysts. A batch pilot plant was constructed at the center and operated to demonstrate this technology to industry. Approximately 1,600 kg of used pellet, monolith, and metal support catalysts containing 1,700 g (54 tr oz) of PGM was processed. Forty-five-kilogram batches of used catalysts were leached with sodium cyanide solution at 160°C for 1 h in a countercurrent processing sequence. This selectively dissolved the PGM. Average extractions from the used pellet catalyst were 96 pet Pt, 95 pct Pd, and 73 pct Rh. Average extractions from the used monolith catalyst were 84 pct Pt, 81 pct Pd, and 66 pet Rh. Heating the pregnant leach solutions to 275°C for 4 h destroyed the PGM-cyanide complexes, causing over 99.7 pct of the PGM to precipitate from solution. The PGM precipitate was predominantly a metallic powder concentrate, typically analyzing greater than 50 pct PGM. Heating destroyed the cyanide to less than 0.2 mg/L free and total cyanide. Both the pellet and monolith residues were evaluated for disposal using the toxicity characteristic leaching procedure developed by the U.S. Environmental Protection Agency.

Jan 1, 2010

By James B. Loftis

The importance of increasing the world's mineral production to help solve our food and energy problems has been widely discussed. Improved surface mining methods will be needed to meet these needs. This paper reviews the modern horizontal drilling and blasting methods which can increase the productivity and lower the costs of I surface mining. A substantial decrease in the number of blast holes required, total footage of blast hole required and amount of explosive used has been realized by many mining companies using this method. Applications of this method are presently in large coal surface mines. However, similar gains are possible and probable in open pit mining of copper and iron.

Jan 1, 1975

By AIME AIME

THE growth of the spirit of progress and mutual aid which motivated the founders of the Institute sixty years ago in Wilkes-Barre was vigorously demonstrated at the sixtieth anniversary meeting held there on May 22. Committees headed by Cadwallader Evans, "resident director" of the Institute, and Paul Sterling, chairman of the local section, had arranged for a full-day tour of the northern anthracite field, so that the hundred and fifty members and guests who had come for the celebration of the anniversary might see the changes and progress made in that field in recent years. More than forty automobiles were in line in the cavalcade which left the Westmoreland Club at nine- thirty. Operations visited were fully described in the May issue of MINING AND METALLURGY, so it is enough to say that after a seventy-five mile drive through the beautiful Susquehanna Valley and over the rolling green hills of northern Pennsylvania a stop was made for lunch at Forest City. Carey, Baxter and Kennedy, contractors at the stripping operations there, had provided, in the shelter of tents, a well-prepared luncheon and other refreshments. The return trip was made by way of Scranton, arriving at Wilkes-Barre at five- thirty.

Jan 1, 1931

By M. J. Gula, S. S. Xue, E. P. Horwitz

A study has been conducted to remove iron from sulfate solutions using Eichrom's Dipexo® extractant, P,P'-di(2ethylhexyl) methanediphosponic acid (H2DEH[MDP]). It is found that this extractant can effectively and selectively extract ferric ion from highly acidic solutions. Ninety-nine percent of the iron was extracted from a simulated feed solution in a single stage. The separation factor, Fe/Zn, was 106. Over 90% of the iron in a loaded organic can be recovered in an aqueous solution by reductive stripping. This paper presents the experimental results. A new process for iron removal using Dipex extractant is described and discussed.

Jan 1, 1999

By Robert B. Parsons

"The last edition of Tax Notes expressed concern about two proposed tax changes in Finance Minister Paul Martin's 1995 budget that could have detrimental effects on Canada's mining industry. This month, Tax Notes expands on these concerns. This article is based on a paper that the author presented at ClM '95 in HalifaxIntroductionOn a global basis, there are more investment opportunities in the mining industry today than at any other time in history. Countries in Central and South America, Eastern Europe, the CIS, Central Asia, and Asia are competing aggressively to attract investment to all sectors of their domestic mining industries. Today, the demand for investment dollars exceeds the amount of dollars that are available for investment in mining. It is not surprising, then, that the established mineral producing nations are witnessing a decline in spending on exploration and development on their home turf, and an increase in spending in developing countries. In the context of a developed country such as Canada, there are two manifestations of the problem of declining investment: (I) Foreign investors are allocating more of their capital budgets to new opportunities in developing countries; and (2) Canadian juniors and seniors are spending proportionately more abroad. This shift in global spending patterns is the source of some concern for the future of Canada's mining industry, particularly because it is widely believed that the current rate of discovery of ore reserves in this country is too low to replenish depleting reserves.""Government bashing"" has always been a popular pastime in Canada. Invariably, this pastime has focussed, at !east in part, on taxation. In view of the intense competition that Canada faces on the global mining scene, it is important that the role of taxation in the decision-making process be kept in perspective. This paper seeks to put the role of taxation into perspective."

Jan 1, 1995

By S J. Schafrik, C Keles, C Schlosser, E S. Gilliland, A K. Louk, N S. Ripepi, S Keim, J Amante, E Diminick

Three legacy coalbed methane production wells have been converted to injection wells for a one-year carbon dioxide (CO2) injection test to evaluate the potential for CO2 storage in the coal reservoir and the potential for enhanced gas production at offset wells. The injection reservoir is composed of 15–20 individual coal seams with an average thickness of 30 cm (1.0 ft), spanning a depth range of approximately 240 (800 ft) to 670 m (2200 ft).The monitoring program for this test includes gas and water sampling of the three injection wells, three dedicated monitoring wells and approximately 20 offset production wells. Key technologies used for monitoring the study area include time-lapse GPS and interferometric synthetic aperture radar (InSAR) acquisitions for surface deformation measurement, a 28-station buried passive microseismic monitoring array, real-time downhole pressure and temperature sensing and perfluorocarbon tracer fluids, which will be injected with the CO2 stream. The schedule for the monitoring program includes pre- (baseline), during- and post-injection data collection. This schedule will allow data to be analysed for time-lapse changes and trends, which are important for understanding the migration of gas and fluid phases in the reservoir – including CO2, methane, other hydrocarbons and water – and for observing the changing distributions of reservoir pressures and stresses.The results of the monitoring efforts for this study have implications for monitoring mining operations. The combined use of GPS and InSAR geospatial data to evaluate elevation changes across and beyond the study area may prove to be an accurate option for measuring surface deformation, including mining-induced subsidence, in unstable terrain. Long-term microseismic monitoring using high-sensitivity instruments has several applications in mining operations, including rock stability monitoring, production monitoring and miner location detection during emergencies. Tracer studies and short-term microseismic monitoring used to assess methane extraction can also be used to develop and optimise degasification systems for underground coalmines.CITATION:Gilliland, E S, Ripepi, N S, Schafrik, S J, Schlosser, C, Amante, J, Louk, A K, Diminick, E, Keim, S, Keles, C and Karmis, M, 2015. Monitoring design and data management for a multiwell CO2 storage/enhanced coalbed methane test in a stacked coal reservoir, Buchanan County, Virginia, USA, in Proceedings Third International Future Mining Conference, pp 47–56 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By Gordon W. Hines

This paper, dealing with network planning in an industrial complex, discusses the type and size of project that can be handled on a manual basis. After a review of the fundamentals of network planning, and specifically of the Critical Path Method, the author analyses several different types of projects, each with its own characteristics. Some can be handled in conjunction with a computer, but others can be dealt with equally well without one. Among the projects discussed are a blast furnace reline, the installation of a billet mill flying shear, and routine maintenance-type operations.

Jan 1, 1967

By Dong Yang, Jicai Han, Xiaoshuang Guo, Tichang Sun, Zhengyao Li

Straw charcoal was used as a novel reductant in the co-reduction roasting of laterite ore and red mud. The influence of the reductant dosages, co-reduction temperature, and co-reduction time were investigated. Results showed that a powdered ferronickel product of 1.81wt.% nickel and 81.40wt.% iron was obtained under straw charcoal dosage of 15wt.% and roasted at 1250 °C for 80 min. The corresponding recovery of nickel and total iron were 97.21wt.% and 98.87wt.%, respectively. The performance of straw charcoal was also compared to that by the conventional coke reductant. Results showed that ferronickel particles using straw charcoal were larger in size than coke, mainly due to the lower S (0.14wt.%) and ash content (3.80wt.%), which could not hinder the agglomeration of the ferronickel grains, and lower melting point that producing liquid phase and promoting ferronickel particles growth. In addition, the gasification reactivity of straw charcoal is better than that of coke, which is beneficial to the iron oxide reduction and the recovery of iron. To conclude, straw charcoal is a promising reductant for the co-reduction of laterite ore and red mud in coal-deficient areas.

Aug 12, 2021