Search Documents

By Isauro Rivera Landero, Martín Reyes Pérez, Eduardo Cerecedo Sáenz, Javier Flores Badillo, Mauricio Guerrero Rodríguez, Juan Hernández Ávila, Eleazar Salinas Rodríguez, María Isabel Reyes Valderrama

During column flotation of mining tailings of the Dos Carlos dam, it was observed that the effect of surface liquid flow (JL) is a variable that determines the rate of rise of packing bubbles and therefore, causes the generation of gas retained within the columnar system. Also overall more stable laminar flows were observed, in a range of superficial flow of liquid in the bottoms stream (JLT) from 0.446 to 0.68 cm/s, showing the stability in the range of superficial gas flow (Jg) from 0.1 to 0.5 cm/s. Observing a uniform bubble size for the three JLT evaluated, with a diameter between 0.05475 and 0.2525 cm, at all the range evaluated of Jg. Furthermore, an uniform performance was obtained, and with the same rate of rise of packing bubbles, showing a greater packing bubbles at JLT = 0.446 cm/s, due to the lesser bubble size observed, in comparison with the values of JLT of 0.68 and 1.017 cm/s.

Mar 1, 2017

By Hsing Kuang Lin

Ferric chloride leaching w.as applied to a complex sulfide ore from Tok, Alaska to dissolve zinc, lead, silver and copper. Gold in the leaching residue, as well as in the ore, is found to be refractory to the conventional cyanidation process. Roasting, pressure oxidation and elemental sulfur removal followed by cyanidation were tested to improve gold dissolution. Also tested were thiourea leaching and high-pressure cyanidation. The readsorption of dissolved gold by carbonaceous matter in the chloride leaching residue was analyzed. Based on the experimental results, factors causing difficulty of gold dissolution from the leaching residue are discussed.

Jan 1, 1989

By A. S. Usmani

The flow associated with the pouring of molten metal into moulds has been modelled on the basis of certain simplifying assumptions. A finite element based Navier-Stokes equation solver has been used to analyse the flow. The velocities obtained from the Navier-Stokes equation solver are used to advect a pseudo-concentration function for modelling the fluid front. A simple problem with a known analytical solution is solved first to test the model. Subsequently, several more examples with varied geometrical configurations are modelled, including one with curved flow boundaries.

Jan 1, 1992

By J. L. Johnson

The U.S. Department of the Interior, Bureau of Mines, investigated recovery of concentrates containing tin, tantalum, and niobium from the Kougarok deposit on the Seward Peninsula, AK. To date, 25 million lb of tin has been delineated in occurrences containing 0.36 to 1.32 pct Sn, and the resource potential is estimated to be as high as 25 million short tons at average grades of 0.75 pct Sn, 0.025 pct Ta, and 0,025 pct Nb. Deslimed ore was concentrated to 54 pct Sn, 0.3 pct Ta, and 0.3 pct Nb, with recoveries of 74 pct Sn and 44 pct Ta/Nb using a Humphrey's* spiral followed by a Deister shaking table. Tin values in the slimes were upgraded to a 5-pct-Sn concentrate using a Bartles-Mozley separator followed by flotation. The 5- pct-Sn was further upgraded by fuming to give a concentrate containing approximately 60 pct Sn. The recovery of the two products combined was 80 pct Sn and 46 pct Ta/Nb, A flowsheet with mill-design parameters resulted from the metallurgical testing. An economic analysis was made based on the proposed process.

Jan 1, 1990

By W. L. Dalmijn

Glass recycling in the Netherlands 'has grown fr.om 10.000 to 300.000 tonnes per annum. The various advantages and problems of the glass cycle with reference to the state of the art in the Netherlands is given. Special attention is given to new technologies for the automated sorting of cullet with detection systems. In Western Europe the recycling of glass has, become a success story. Because of this, the percentage of ,glass cullet used in ,glass furnaces has increased. To meet the quality demands of the glass industry, automated sorting for the removal of stones, non-ferrous metals and other impurities ,had to be developed and incorporated in glass recycling plants. ;In Holland, Germany and other countries, the amount of glass collected has reached a level that colour-sorting becomes necessary to avoid market saturation with mixed cullet. Recently, two systems for colour-sorting have been developed and tested for the separation of bottles and culletin the size .range of 20 -50 mm. With the increased capacity of the new glass recycling plants, 120,000 -200,000 tpy, the quality systems have also to be improved and automated. These quality control systems are based on tile automated sorting technology developed earlier. for the glass recycling plants. The data obtained are automatically processed and printed. The sampling system and its relation to the theory of Gy will be described. Results of both developments in glass, recycling plants will be described.

Jan 1, 1995

By Andrea Bernardes

Printed circuit boards (PCBs) of varying compositions have been converted by incineration and following melting into an environmental agreeable slag and a copper-nickel-tin alloy, containing the precious metals. The environmental compatibility of the slag was determined according to the German standard DIN 38414 - Part 4; pollutants' concentration in the lixiviates is smaller than the thresholds of drinking water (CE-Standards). Each experiment the charge were 500g scrap from PCBs and ca. 100g slag forming material. The products were a kind of mullite slag, poor on iron, which was recirculated, and an alloy containing up to 0.3% Gold. With a burner to the retort coal gas, the waste gas was burned without soot, and the produced mixed zinc-lead oxide containing silver was collected in the flue dust.

Jan 1, 1997

By lonkion M. Font

Due to the known disadvantages of the use of iron silicate slag in the nickel converting stage, i.e., high metal losses, high magnetite content, and low fixation of impurities in the slag, the development of the new proposed "ferrous calcium silicate slag" for smelting and converting processes of nickel is very promising. Hence, considering the successful experimental results of using CaO base slag for the nickel smelting process, a study based on a detailed comparison for the phase equilibrium, and the minor elements distribution between the NilS2-FeS matte with either FeOx-CaO or FeOx-Si02 base slag was investigated. The main results are summarized as: no difference in the nickel losses between both slags was found at high nickel content in the matte, and the fractional distribution analysis for arsenic and antimony pointed out their preferential fixation in the calcium ferrite slag rather than in the iron silicate slag. Considering the energy and pollution issues, the technical feasibility of using calcium ferrite slag in a converting process of the Bessemer matte will have a prominent future for the nickel industry.

Jan 1, 2003

By Jianjun Wang, Jiaqing Peng, Lingen Luo, Zhenbang li, Yinghe Lin

Copper removal from ferronickel by FeS has been exploring studied. It is found that the decopperizing agent FeS makes the copper removal in ferronickel effectively. The effects of FeS addition amount, carbon content in ferronickel and experimental temperature were investigated. The results showed that the removal rate of copper in ferronickel increased with the amount of FeS increasing. When the dosage of FeS is 20% (mass percentage)，the removal rate of copper can reach higher than 11%. The rate of copper removal rises with the amount of carbon content increasing in ferronickel. When the amount of carbon content is 1.86%, the removal ratio of copper is 41.3%. Higher experimental temperature promotes the copper removal reaction in certain extent. The flux is acidity and weak oxidative can also promote the reaction of copper removal.

Jan 1, 2015

By Edgar Peek

"The two dominant metallurgical problems in treating most base metal sulphide concentrates in both the chloride and sulphate system are iron removal and sulphur elimination, respectively [1-3]. In this paper the opportunities, limitations and fundamentals of the chloride metallurgy system are described against this background. Only the treatment of oxide and sulphide ores is considered. Both hydrometallurgical and pyrometallurgical unit process operations are highlighted, since most successful base metal processes are based on a combination of the two. Hence, an overview of the technical and also some economical aspects of chloride metallurgy are presented.This overview summarizes the successful applications of chloride metallurgy, but it will not give exhaustive process and plant descriptions. It predominantly focuses on the essential technical features of the metallurgical unit process operations, while providing numerous references separately."

Jan 1, 2011

By Mitsutaka Hino

The contents of gangue minerals, such as A1203, P205, crystalline water and so forth in the iron ore imported to Japan tend to increase year by year, Though the increments of such gangue contents are approximately 0.1-0.2 mass%, some problems for the blast furnace operation in ironmaking process have already been reported, In order to clarify the mechanism of harmful effect caused by the small increment of gangue minerals, mainly A1203, on the blast furnace operation, the dripping behavior of FetO-CaO-SiO2-AI2O3-MgO slag from the iron funnel, which simulated the micro-porosity in sinter ore, has been observed with the wide range of basicity, Al2O3, FetO and Mgo contents. The effect of MgO on the dripping behavior of slag has been summarized in this paper, It was found that the addition of 2mass% MgO resulted in large increase of hold-up on the most of the conditions. When FetO content was less than 20mass% and the basicity was lower than 0.8, MgO lowered the hold-up even if the slag contained 10mass% Al2O3. Every slag hold-up showed the minimum at the basicity of less than unity on the conditions of constant FetO and A1203 contents. This trend became remarkable when the slag contained 2 mass% MgO.

Jan 1, 2003

By Motang Tang, Chaobo Tang, Shenghai Yang, Lulu Guo, Yun Li, Yongming Chen, Jing He

A new innovative process for one-step and cleaner extraction of lead from spent lead-acid battery by reductive sulfur-fixing smelting was presented. This paper summarized and discussed several potential sulfur-fixing agents and molten salts which can be used in this new technique. Thermodynamic analysis involving reaction mechanism, ΔGT and predominance-area diagrams of different smelting systems were performed, respectively. The results proved the technical feasibility and high-efficiency of this process. Copper oxide ash (CuO), zinc oxide ash (ZnO) and iron oxide bearing residues (FexOy) can be used as sulfur-fixing agent to extract lead through exchange reactions. Sulfur-fixed efficiency of CuO, ZnO and FeO decrease slightly in turn. Sulfur contained in PbSO4 is fixed in form of Cu2S, ZnS and FeS respectively which avoids SO2 emission. The addition of molten salt can significantly decrease temperature of reductive sulfur-fixing reactions. Molten salt can be regenerated and recycled in smelting system after filtering solid residues.

Mar 1, 2017

By Farhang Hedjazi

Anglo Asian Mining have recently installed an industrial-scale UF/RO plant to treat process liquors from the integrated heap leach/agitation leach/ resin-in-pulp gold ore treatment facilities at their Gedabek gold-copper mine in Azerbaijan. The UF/RO plant is designed to treat 60 m3/h of leach solution to produce discharge quality water. The RO concentrate, which contains elevated concentrations of copper, silver and cyanide, is sent to the company’s SART plant for the recovery of the metal values as a precipitated sulphide concentrate and the cyanide, which is recycled to leaching. The new water treatment plant improves the sustainability of the operations at Gedabek by enabling replacement of fresh water input with RO permeate and safe discharge of permeate to the environment, during periods of excess water balance. The paper includes pilot plant data and early results from the full-scale plant.

By D. D. Rodier

Most zinc concentrates contain some silver and varying amounts of such valuable trace elements as gold, indium, germanium and gallium. With increasing similarities in plant installations, the predominance of electrolyte process and the increasing environmental constraints on iron disposal, it is essential that zinc smelters optimize the recovery of any valuable elements in their feed stocks. The process options, to date, of smelting, flotation or leaching of silver-rich leach residues cannot be applied economically to all installations. It is therefore necessary that new innovative processes, to recover silver and other valuable metals from relatively low grade feeds, be developed. This paper attempts to place this strategy in the context of today's constraints and will also provide a simple evaluation tool for any process alternatives.

Jan 1, 1990

By Nobumasa Kemori

Six kinds of copper '90ncentrates. were treated individually in a ,pilot scale. Outokumpu flsah smelting furnace ~n order to study their ?flash smelting behavior with respect to oxygen efficiency and dust generation. The copper concentrates tested were selected from the more than twenty sources which are treated at the Sumitomo Toyo copper smelter, so as to provide a wide range of chemical composition in terms .of Cu, S,Fe, Pb + Zn + As, and Si~ content. Oxygen efficiency 'and dust generation rates obtained in 'the experiments ranged from 80% ,to 108% and 11% to 20%, respectively. Relationships between these results and experhnental conditions such as chemical and mineral composition of the copper concentrates, flux ratio, fuel consumption and so on are also discussed quantitatively in this paper.

Jan 1, 1998

By William Petruk

The development of automatic image analysers brought the application of image analysis into process mineralogy because the analysers can measure parameters more easily, quickly and accurately than by manual grain counting techniques, and can also collect data unobtainable by manual grain counting. Data from ore specimens and mill products are used to predict and to define the behaviour of minerals during processing. The analyses are generally performed on the basis of either surface areas or linear intercepts of grains in polished or thin sections, and the data are computer processed to give mineral quantities, liberations, size distributions, and characteristics of middling particles. For analysis, the minerals must be detectable and discriminatable from each other. An image editor is usually used when minerals are not easily discriminated. In addition BSE-8EM photographs have been used where the silicate minerals could not be discriminated from the mounting media. Methods of analysis, typical results, and their applications are discussed.

Jan 1, 1982

By Zhang Hanbo, Niu Liping, Zhang Zhiqi, He Jicheng, Dou Zhihe

"Rutile, ilmenite and Al-Ca complex reducer were used to prepare high titanium ferrous alloy by enhanced reduction-SHS method. The effects of the complex reducer compositions and slag types on the enhanced reduction-SHS process were investigated. The high titanium ferrous alloys were characterized by XRD and SEM. The results indicate that the high titanium ferrous alloys consist mainly of TiFe2, AlTi3 and Al2O3. The oxide inclusions exist resulting in directly the high oxygen content and micro-structural defects in the alloys. The titanium and oxygen contents decrease, but the aluminum content in the alloy increases while the mass ratio of calcium in the Al-Ca complex reducers increases. When the mass ratio of Al/Ca in the Al-Ca complex reducer is 6:1, titanium, oxygen and aluminum contents are 63.75%, 3.01% and 10.72% respectively. When the mass ratio of Al/Ca is 5:1 titanium content is 55.00% nearly and aluminum content is higher than 14.00%, but oxygen content is lower than 2.0%.1. IntroductionThe high titanium ferroalloys with 65%~75% titanium have the advantages of low melting point and high titanium content. They are widely used in special steel refining, while they are also a kind of very important quality orientation alloys in the rage of aviation and aerospace. At present, the methods of preparing high titanium ferroalloy include vacuum remelting and thermit reduction. The alloys prepared by the vacuum remelting method have good qualities and low oxygen content, so it is widely used in Russia, Western Europe and other developed countries. In China, there are abundant rutile resources, but waste titanium is lack, therefore, the preparation method is the thermit reduction. But there are many quality defects in the high ferrotitanium alloy, including high oxygen content, unstable quality and so on. In order to improve the qualities of the high titanium ferroalloy, especially to reduce oxygen content, the domestic and overseas have done a lot of further researches. For example, Sichuan E-mei ferroalloy plant and Beijing Nonferrous Metal Research Institute have prepared high titanium ferrous with 73.77% titanium with natural rutile, but the oxygen content is high. Through controlling the quality of raw material, they obtained the better qualities, but the oxygen content is still very high. South Africa Mintek company have prepared high titanium ferrous alloy with low nitrate by plasma heating under the isolation air conditions, but they couldn’t also remove effectively oxygen in the alloy. The oxygen exists in the form of Al2O3 and titanium protoxide. So it can be speculated that except TiO2 not being fully reduced, the no-sufficient alloy-slag separation is the direct reason resulting in high oxygen and poor microstructure. In view of present technical difficulties during preparing high titanium ferroalloy by thermit reduction, this paper proposed a new method of preparing high titanium ferrous with low oxygen by enhanced reduction-SHS with Al-Ca complex reducer. Ca in Al-Ca complex reducer has stronger reductive ability, it can effectively strengthen the reductive degree of TiO2. The slagging agent CaO CaF2 and MgO can effectively reduce the viscosity of Al2O3 slag to improve its liquidities to strengthen alloy-slag separation effects so that to remove inclusions and oxygen. In this paper, effects of slagging agent type on the reduction and the qualities of high-titanium ferroalloy were studied."

Jan 1, 2012

By Godwin J. Igwe

For soil remediation technology to be effective, a thorough understanding of the interactions between a targeted contaminant and the soil matrix is crucial. Proper selection of remediation technology, based on understanding the bonding/binding characteristics of the soil and contaminant, can often result in significant remediation cost savings. Contaminated soil cleanup is complicated by both the physical nature of the soil formation and the behavior of contaminants introduced into the formation. Contaminants can exist in the subsurface in different phase attached to the soil surfaces, dissolved in the ground water, or occupying pore spaces as a separate gaseous or liquid phase. Contaminants properties and how they exist in the subsurface influence their toxicity, mobility and treatability with different remediation technologies A soil characterization study was performed to provide information for remediation technology selection for an inorganic lead contaminated soil. The soil pH, TCLP analysis, thermogravimetric analysis, the soluble anions and cations present, equilibrium leaching tests, analysis by x-ray fluorescence, sequential extractions and speciation analysis using scanning electron microscopy, were all used. Results provided many insights into contaminant behavior in the soil, indicating ultimately whether soil washing or solidification/ stabilization remediation technologies were applicable.

Jan 1, 1994

By Jian-guang Yang, Lei Jie, Si-yao Peng, Jian-ying Yang

A new membrane electrolysis process for bismuth recovery from bismuthinite concentrate was introduced. Under the conditions of temperature 70 degrees C, acidity 3 mol/L, solid liquid ratio 1:4 and 1.1 times stoichiometry sodium chlorate dosage for 1.5 h oxidation leaching, more than 98.5% bismuth can be leached from bismuthinite concentrate. The resultant leach solution was subjected to membrane electrolysis. Under the conditions of NaCl concentration 300 g/L and pH 7 in anolyte, bismuth ions concentration 80 g/L and HCl concentration 3 mol/L in catholyte, heteropole distance 6 cm, temperature 40 degrees C and current density 200 A/m2, a flat deposited bismuth plate can be obtained after 24 h electrolysis, and the bismuth purity was more than 99%. The current efficiency of cathode was 97.88%. Chemical component analysis results showed that the average convert efficiency of the sodium chlorate was 52.77% and the average oxidizing efficiency of chloride ion was 69.78%, and the resultant anolyte generated in anode compartment could be fully reused as oxidant for leaching bismuthinite concentrate again.

Mar 1, 2017

By Fernando Aracati Botelho, Jose Antonio Silva Souza, Luis Alves Venancio, Emanuel Negrão Macedo

"1 AbstractThe production of alumina from bauxite using the Bayer process generates 0.7 to 2.0 ton of the residue known as red mud and about 800 kg of CO2 per ton of alumina. The direct use of exhaust gases to react and neutralize the bauxite residue may allow a double gain: open a wide range of new applications for bauxite residue reducing its reactivity and sequester from 3 8 to 107 kg of CO2 per ton of alumina. This paper shows a pilot scale reaction of a suspension of bauxite residue-water with flue gas produced from direct burning oil, similar to the exhaust gases of a refinery. Two different types of reactors are used, a spray tower and a packed column. The inlet and exhaust gases are analyzed using electrochemical cells and non-dispersive infrared sensors. The pH of the suspension is monitored during the reaction and after to evaluate the buffer effect. 2 IntroductionThe production of millions of tons per year of alumina around the world generates from 0. 7 to 2.0 ton of the residue known as red mud (RM) per ton of alumina. The vast majority of the red mud is stored in large sealed lakes. Due to the high reactivity this material is considered dangerous and currently there is no operating process capable of reusing all the material produced at any refinery. These lakes after filled of solid material eventually have the surface revegetated [4]. In any case they will remain as an environmental passive and needs monitoring for decades. The search of a industrial process that combines the reduction of the CO2 emission and the reduction the pH of the red mud opening the possibility of large scale and economically viable ways is the main objective of this work.The use of the exhaust gases of the refmeries to neutralize the bauxite residue may allow a double gain: Open a large array of new applications for the residue with the reduction of its reactivity and sequester millions of tones ofCO2 plus other gases like SO2 [7] and NOx. This project studies the reaction of the exhaust gases from a boiler burning diesel with RM in different reactor types and conditions in order to obtain parameters to design equipment capable of process this reaction on a larger scale. With these objective compositions of red mud were processed with flue gas at concentration similar to the exhaust gases of the calcination process and boilers of the refmeries."

Jan 1, 2012

By J. N. Hartley

Samples of ash from the May 18, 1980, eruption of Mt. St. Helens Were collected from several locations in eastern Washington and Montana. The optical microscope and the combined scanning electron microscope with energy dispersive x-ray microprobe were used to determine the composition and mineralogical characteristics of the samples. In addition, a quantitative image analyzer was used to examine the particle size distribution, and x-ray diffraction was used to identify major minerals. Both polished sections and ultra thin sections (less than 5 ~m in thickness) were prepared to study the mineralogical characteristics. The use of ultra thin sections provided access to microstructural detail. Mineralogically, the samples ranged from almost totally glassy to almost totally crystalline. Crystal-line samples were dominated by plagioclase feldspar (andesine) and ortho-pyroxene (hypersthene) with smaller amounts of titaniferous magnetite and hornblende. Nearly all the samples contained from less than 1 to 3 wt% free crystalline silica (quartz, trydimite, or cristobalite).

Jan 1, 1981