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By Daoxin Wu

In this paper, the rutile TiO2 were prepared under air, Ar and H2 calcination atmosphere by low temperature hydrolysis using Tetrabutyl titanate (C16H36O4Ti) as raw material. Powers were characterized by X-ray diffraction, UV-vis diffuse reflectance and X-ray photoelectron spectroscopy. The influence of the calcination atmosphere on the photocatalytic reactivity of rutile TiO2 for oxygen production was investigated. The photocatalytic reactivity of rutile TiO2 prepared under air, Ar and H2 atmosphere was compared under ultraviolet and visible light radiation with Fe3+ (c=8.0mmol.L-1) as electron acceptor. The results showed that rutile TiO2 prepared under Ar and H2 atmosphere had higher photocatalytic activity for oxygen production than that prepared under air atmosphere. The oxygen production rates under ultraviolet irradiation were 427.5, 378.2 and 357.0µmol.l-1h-1 respectively when rutile TiO2 was prepared under Ar, H2 and air atmosphere. The oxygen production rates under visible light irradiation were 78.2, 52.2 and 13.5µmol.l-1h-1 respectively when rutile TiO2 was prepared under Ar, H2 and air atmosphere.

Jan 1, 2008

By Liang Li

Thermodynamic analysis and experiments were conducted in order to verify the feasibility of preparing crude titanium tetrachloride (TiCl4) via the carbochlorination of low-grade titanium slag in molten salt. Titanium slag, assaying 74.6 wt% TiO2 with high calcium and magnesium oxide impurities, was treated by an optimized carbochlorination process in NaCl molten salt. These impurities in the titanium slag were chloridized simultaneously, and chlorination products FeCl2, MnCl2, MgCl2, CaCl2 and CrCl3 were collected in the furnace slag. XRD and SEM/ EDS analysis of residue shown that SiO2 and Al2O3 in titanium slag were difficult to chlorinate completely. Theoretical calculations and industrial-scale experimental studies reveal the content of TiCl4 in the products was more than 98.8 wt% and thus proved the feasibility of utilizing low-grade titanium slag for TiCl4 preparation by molten salt chlorination technology.

By Yuuki Yoshida

Electrolytic manganese dioxide, EMD, is the positive electrode material of primary batteries and the raw material of LMC used as the positive mass of lithium ion batteries and is currently produced by anodic deposition on and harvesting from a titanium anode in acidic manganese sulfate solutions prepared by dissolving high purity of manganese sulfate into sulfuric acid solutions. This paper presents an alternative method of EMD production using a novel anode, Mn2O3 coated titanium, at lower operating temperature than the current process to explore a possibility of manganese recovery from zinc electrowinning solutions. The Mn2O3/ Ti anode prepared by thermal decomposition of a precursor solution containing Mn (II) showed the anodic deposition of MnO2 by constant current electrolysis and the current efficiency was 95% in maximum, while the current efficiency and the crystallographic structure of deposited MnO2 depended on the current density, the electrolysis time, the bath temperature, and the concentration of Mn(II). The deposited MnO2 was successfully harvested from the anode and the recovery rate was 98%.

By B. C. Tripathy

The effects of alkali metal ions Li+, Na+, K+and transition metal ions Cr3+ and Mo6+ on the cathodic current efficiency, deposit quality, crystallographic orientations, deposit morphology and polarisation behaviour of the cathode during nickel electrocrystallisation on stainless steel substrate from aqueous sulphate solutions containing boric acid were investigated. The alkali metal ions had virtually no effect on the cathodic current efficiency, deposit quality, crystallographic orientations, deposit morphology and cathodic polarisation. On the other hand, there were significant variations in the current efficiency and deposit characteristics when Cr3+or Mo6+ were present in the electrolyte. Current efficiency decreased by more than 10% even at lower concentrations (> 100 mg/L). Similarly purity of the deposits was affected by the presence of either of the metal ions. In the presence of Cr3+, there was progressive shifting of the nucleation potential of nickel towards more negative values, whereas, in the case of Mo6+the nucleation potential shifted initially towards positive values in the concentration range 2-40 mg/L, but then towards negative values when its concentration exceeded 40 mg/L.

Jan 1, 2003

By Thomas F. Nederpel

The production of zinc and zinc-aluminum coated strip can be reasonably accomplished on a single operating unit. However, if the hot dip coating line is equip d with only one mo 7 ten metal holding furnace, it is necessary to transfer liquid metal of different chemistries and reintroduce virgin material to obtain the 18" necessary balance of elements in the bath. Dofasco produces Galvanize and Galvalume on a coating line with a sin le liquid metal furnace and has developed not only an efficient liquid metal trans& system but also an effective means of reutilizing the zinc-aluminum mixtures without detrimental quality affects.

Jan 1, 1992

By M. Kawakami

In the blast furnace, the reduction of iron oxide and gasification of coke occur simultaneously. It is well accepted that the gasification reaction controls the simultaneous reaction. Therefore, it is important to develop highly reactive carbonaceous materials. It is also known that the reaction is accelerated catalytically with the addition of some materials. In the present work, the catalytic effect of iron, nickel and CaO on the gasification of graphite and coke was examined. The catalytic effect of iron, nickel and CaO on the reaction rate of graphite was noticed The effect was larger at lower temperature. At 1373 K, the effect almost vanished. The effect was larger in the order of CaO, iron and nickel. The reaction rate of de-ashed coke increased by the addition of iron and nickel. The effect of iron was larger than that of nickel. The effect was larger at higher temperature, which was contrary to the case of graphite. The reactive surface area increased also by the addition. Therefore, the catalytic effect on reaction rate might be attributable to the increase in the reactive surface area.

Jan 1, 2006

By Randy Martin

"Greenstone Resources Ltd. constructed and operates the Santa Rosa open pit, heap-leach gold mine in Veraguas, Panama. The project was commissioned in 1995 at a designed capacity of 1.8 million tons per year. The ore exhibits a long leach up to three years, and requires three stage crushing to minus 3/8 inch to achieve on average a 74% gold recovery. The crushing plant is required to handle high volumes of clay and the circuit includes a Barmac Crusher. Panama receives over 3 meters of rain annually and Greenstone is using innovative means to control the project's water balance. Greenstone has developed a successful approach to operating a low grade (1.5 gm Au/T) deposit under difficult operation conditions.ABSTRACT ONLY"

Jan 1, 1997

By Keith Cramer

As a leader in the development of metal extraction technology, Avecia continues to pioneer advancements for the processing of copper through leach, solvent extraction, and electrowinning of copper. From the initial patent of the second generation of oxime 5- nonylsalicylaldoxime in the 1970's; to the effective use of modifier technology; and development of computer assisted modeling programs, Avecia is driving SX technology to maximize extraction productivity. Keys to consider when advancing productivity are: 1) high quality, high performance products; 2) a responsive, partnering approach to technical service; and 3) tools to aid in the education of industry wide technical personnel with a view on continuous improvement. The focus of this paper is on the advancement of tools to aid in the education for optimization of processing copper through solvent extraction. One such tool is Avecia's own customized solvent extraction modeling program called MEUM. MEUM is currently used world wide to analyze plant operations, test ideas for improving operations, assist engineering companies in design, and to teach basic solvent extraction concepts. Recently MEUM has also been incorporated into a University setting. In the spring of 2000 Avecia worked with the University of Melbourne to integrate MEUM into their Mass Transport tutorial class. Students completed exercises to evaluate how operational changes affected a solvent extraction plant's performance. This paper introduces the basic functions of the program and discusses the successful implementation of MEUM into the University of Melbourne curriculum.

Jan 1, 2002

By De-qing Zhu, Zi-fu Gao, Jian Pan

"In order to produce high quality metalized products and prevent from burden cohesion during pre-reduction, self-fluxed pellets were made for COREX process in the paper. The effects of reduction temperature and reducing gas composition on pre-reduction behaviors of self-fluxed pellets are studied. The results show that the prereduced pellets have poor quality and deposited carbon appears when the reduction temperature is between 600°C and 700°C. The metallization rate, reduction degree and compressive strength of prereduced pellets are promoted by the elevating reduction temperature and mole fraction of H2. Pellets reduced by pure H2 at 800°C have high metallization rate (96.2%), reduction degree (99.4%) and compressive strength (960N/pellet). In all tests, self-fluxed pellets display normal swelling (RSI<l5%) behavior which reveals that self-fluxed pellets are suitable for COREX process. Increasing reduction temperature and mole fraction ofH2 in reducing gas is benefit for pre-reduction of pellets.IntroductionCompared with Blast Furnace, the COREX process has advantages of short flow sheet, using non-coke coal and high-energy utilization. Acidic pellets and lump ores are the chief iron- bearing burden for COREX process which could lead to low melting point substance appearing in per-reduction process. In addition, the acidic hematite pellets tend to swell during the reduction [1-3]. This will result in decreasing compressive strength of pellets, burden cohesion, bad air permeability and poor work status in shaft furnace. Adding carbonate flux could restrain burden bonding to some extent in actual production, but decomposition of carbonate flux increases energy consumption. Worse still, weak reduction potential is unfavorable to iron material reduction [ 4, 5]."

Jan 1, 2013

By Liangying Wen, Xuewei Lv, Yuelin Qin, Feng Zhu, Guibao Qiu, Chenguang Bai, Meilong Hu, Shengfu Zhang

"The COREX process is the first reduction ironmaking technology with coal and pure oxygen to get high quality hot metal, which consumes a lot of high quality lump coal and some coke. In order to increase the utilization of fine coal, reduce coke consumption and enhance the competitiveness of the technology, the combustion behavior of pulverized coal injection in melter gasifier is studied experimentally. The results show that the combustion rate of PCI increases with the increase of temperature. And the combustion rate increases with decreasing coal particle size. Compared bituminous coal with anthracite, the former’s burning ratio is higher than the latter in the same granularity. The combustion effect is remarkable when coal blend of bituminous coal and anthracite with the smaller particle size is pulverized in COREX process.IntroductionThe COREX process is the first reduction ironmaking technology with raw coal and pure oxygen to get high quality hot metal, which consumes a lot of high quality lump coal [1-3]. However, the proportion of lump coal in raw coal is very small, and it is avoidless to produce fine coal because of mechanical coal cutter and storage and transportation process, so it is important to resolve utilization of fine coal in COREX ironmaking process in order to energy conservation and reduce the cost of hot metal [4]. Currently, Coal briquetting technology is adopted to utilization of fine coal in COREX process [5], but coal briquetting system has high investment cost and requires feasible adhesive agent. The pulverized coal injection (PCI) into a blast furnace is being used on a global scale to improve the stability and reduce the cost of blast furnace operations [6]. The successful development of PCI in blast furnace is contributed to pulverized coal in COREX melter gasifier. However, it is different in PCI process between COREX melter gasifier and blast furnace, and the differences are as follows: firstly, The air is injected into blast furnace, which temperature is about 1200 ?, but in COREX melter gasifier the normal temperature oxygen is blasted, so PCI in blast furnace begin burning in blowpipe, but the combustion of PCI in COREX melter gasifier is only in raceway. Secondly, the racway of COREX is smaller than that of blast furnace of the same size. So, the combustion behavior of PCI is complex in COREX melter gasifier, which is not use for reference."

Jan 1, 2012

By J. -P. Nepper

It has been possible to largely contain converter aisle emissions of SO2 and fumes in the case of batch-wise operated Peirce Smith converters during normal blowing periods with the help of suitably designed primary hoods. Controlling the escape of off-gas during the periods of turning the converter in or out of the stack has been problematic in the past. Effective automated control systems have been developed for the purpose and successfully applied in smelter operations in Spain, Taiwan and Germany. This has led not only to an effective reduction of emissions in the converter environment but also to an improvement in the converter operation.

Jan 1, 1992

By R. S. Tahautdinov, A. N. Posazhennikov, V. V. Bastrygin

"The Bakal (South Ural, Russia) deposit of iron ore bearing iron carbonate (siderite) with the capacity of more than 1 billion tones belongs to the MMK. This ore cannot be fully processed via blast furnace technology because of high content of MgO. According to the investigations carried out in the USA and Japan in 1999-2004 the ITmk3 (Ironmaking Technology mark three) RHF technology is a breakthrough in Ironmaking. Four iron ore types (hematite, magnetite, high and low Al2O3/SiO2) were tested. Reduction, melting and slag removal can be achieved in just 10 min. The main objective of the investigation is to establish optimum operation conditions for the production of iron nuggets from iron carbonate bearing ore via the ITmk3 by means of the lab scale testing. Samples of iron ore and carbon reductant were chemically and physically analyzed. Green pellets were processed via a lab tube furnace to simulate RHF conditions. The nuggets and slag were chemically analyzed. This preliminary test work provides valuable information which may be used for large-scale testing in a commercially sized RHF.IntroductionThe ITmk3 process upon which this paper focuses was developed by Kobe Steel in its research facilities in 1996 [1]. After pilot testing at Kobe Steel’s Kakogava Works in 1999-2004 the pilot demonstration plant was built and operations were successfully carried out by Mesabi Nugget joint venture in 2002-2004. Steel Dynamics has committed to building the commercial plant at the Mesabi Nugget site in Hoyt Lakes (Minnesota). Only 4 iron ore types (hematite, magnetite, high Al2O3/SiO2 and low Al2O3/SiO2), as well as 4 coal types with range of volatility, ash and fixed carbon were tested. Results were consistent with nugget characteristics confirming ITmk3’s flexibility with respect to raw material inputs. At the same time, no research in the field of nugget from iron carbonate bearing ore with high content of MgO has been done. Such kind of iron ore is restricted for charging into the blast furnace due to contamination of MgO. The reason for restriction is the limitation of load of MgO in the blast furnace. If a lot of MgO enters the blast furnace, slag becomes viscous. The viscous slag is obstacle for stable operation of the blast furnace."

Jan 1, 2011

By E. V. Redin

"The Bakal (South Ural, Russia) deposit of iron ore bearing iron carbonate (siderite) with the capacity of more than 1 billion tones belongs to the MMK. This ore cannot be fully processed via blast furnace technology because of high content of MgO. According to the investigations carried out in the USA and Japan in 1999-2004 the ITmk3 (Ironmaking Technology mark three) RHF technology is a breakthrough in Ironmaking. Four iron ore types (hematite, magnetite, high and low Al2O3/SiO2) were tested. Reduction, melting and slag removal can be achieved in just 10 min. The main objective of the investigation is to establish optimum operation conditions for the production of iron nuggets from iron carbonate bearing ore via the ITmk3 by means of the lab scale testing. Green pellets were processed via a lab tube (chamber) furnace to simulate RHF conditions. This preliminary test work provides valuable information which may be used for large-scale testing in a commercially sized RHF.IntroductionThe ITmk3 process upon which this paper focuses was developed by Kobe Steel in its research facilities in 1996 [1]. After pilot testing at Kobe Steel’s Kakogava Works in 1999-2004 the pilot demonstration plant was built and operations were successfully carried out by Mesabi Nugget joint venture in 2002-2004. Steel Dynamics has committed to building the commercial plant at the Mesabi Nugget site in Hoyt Lakes (Minnesota). Only 4 iron ore types (hematite, magnetite, high Al2O3/SiO2 and low Al2O3/SiO2), as well as 4 coal types with range of volatility, ash and fixed carbon were tested. Results were consistent with nugget characteristics confirming ITmk3’s flexibility with respect to raw material inputs. At the same time, no research in the field of nugget from iron carbonate bearing ore with high content of MgO has been done. Such kind of iron ore is restricted for charging into the blast furnace due to contamination of MgO. The reason for restriction is the limitation of load of MgO in the blast furnace. If a lot of MgO enters the blast furnace, slag becomes viscous. The viscous slag is obstacle for stable operation of the blast furnace."

Jan 1, 2012

By F. Sanchez, A. Mejias, C. Frias, G. Diaz

"Crude zinc oxides are the major source of secondary zinc and are produced from fuming processes like Waelz kilns. The impurities of crude zinc oxides make difficult their processing in primary zinc refineries due to mainly high chloride tenor. Washing with sodium carbonate is a costly operation and chloride removal efficiency is not good enough, so further purification steps are required. The crude zinc oxides are easily treated using ZINCEX™ technology based on leaching, solvent extraction, and electrowinning. The ZINCEX™ process is commercially available and is designed to be a perfect barrier for metallic impurities and halogens, allowing selective zinc extraction in mixed chloride and sulfate leaching solutions. Other valuable components as lead and silver can be efficiently recovered from the leaching residue using PLINT technology in chloride media. Silver is recovered as silver cement and lead is precipitated as pure lead oxide or carbonate, which can be smelted at low temperature.IntroductionZinc is a fully recyclable metal and at present approximately 70% of the zinc produced worldwide comes from primary zinc while 30% originates from secondary materials. Nowadays, the zinc recycling rate is continuously increasing mainly through galvanized steel scrap processing, and crude zinc oxides are the major source of secondary zinc [1]. Secondary zinc oxides are obtained from fuming processes like W aelz Kiln, Rotary Hearth Furnace or Primus Furnace. Waelz is the dominant technology accounting for 80% of total crude zinc oxides production worldwide. In the Waelz process, steel dust is mixed with solid fuel reductant (coke breeze) and pelletized. It is then fed to the kiln and heated to a reaction temperature of l ,200°C. In such conditions, zinc, lead, and other non-ferrous metals are vaporized into the flue gas together with chlorides and alkaline metals. Mixed oxides are drawn from the kiln with the process gases and separated to produce typical crude zinc oxides [2]."

Jan 1, 2011

By Cyro Takano

An alternative use for recycling of waste from bag house of iron ore sinter plant was tested by producing and evaluating" at laboratory scale, the self reducing cold bonded pellets. This waste was characterized and the self-reducing pellets were produced using anthracite coal fines as reductant and Portland cement or hydrated lime/Blast Furnace slag as binder. It was used the molar ratio of Fe2O3/C (fix) equal to 3. Evolution of cold strength with curing time, for different contents of binder, was evaluated. Cold strength of 200N/pellet was obtained, for sinter dust, after 10 days of curing. Suitable hot strength was also presented and no decrepitation and swelling were observed. Good fractional reduction was obtained at 950°C and 1137°C. These results show that this material may be used by the Self-Reducing Processes for hot metal production, as an alternative route for this dust destination.

Jan 1, 1996

By R. Cameron

The growing use and acceptance of electric vehicles (EV), as evidenced by the record sales of over 750 thousand vehicles in 2016 and a current global EV stock of 2 million vehicles, is putting pressure on sourcing raw materials such as cobalt, and to a lesser extent, nickel. Global supply is poorly diversified, with 50– 60% of global cobalt production sourced solely from the Democratic Republic of Congo (DRC). One potential source for cobalt and nickel are low-grade nickeliferous pyrrhotite tailings, of which 50–100 million tonnes are present in the Sudbury area alone. This paper presents the extraction of cobalt and nickel from this material using a combination of flotation and bioleaching technologies. The findings of a high-level techno-economic analysis of the proposed processing flowsheet are presented.

By Edita Vircikova

The best demonstrated available technology (BOAT) for the removal of dissolved arsenic and some heavy metals as reported by USEPA (Contaminants and Remedial Options at Metal Sites, Draft Report, August 1993) (1) is still the chemical precipitation. Coprecipitation with the excess of iron is usually practised because of the availability of iron at low/no cost and also in order to meet the stringent regulatory discharge limits. The arsenic is usually removed with iron because of its common occurence in the mined orebodies and the excellent adsorptive property of the precipitated hydrous ferric oxide compounds. There has been controversy, however, over the long-term stability of the arsenic-bearing ferrihydrite which is produced.

Jan 1, 1995

By Junji Shibata

As one of the effective usages of various wastes discharged in non-ferrous metal industry, the synthesis of hydrotalcite was carried out using aluminum dross as a raw material. Hydrotalcite is one of the inorganic anion exchangers and has layered structure of complex hydroxide. The removal of toxic metal ions such as As(III), As(V), Cr(VI) and Se(IV) with the hydrotalcite was investigated, and the removal properties were compared from the viewpoint of the anion exchange amount and exchange rate. Hydrotalcite can be obtained by a co-precipitation method from the aluminum dross and the waste MgCl2 solution discharged in an aluminum regeneration process. Slight amounts of SiO2, Al2O3, Fe2O3 and so on remain in the reaction product as an impurity component. Interlayer distance of the obtained hydrotalcite is about 0.3nm. Hydrotalcite changes to Mg-Al oxide by the calcination at 773K for 3h, and then hydrotalcite is formed again by a rehydration operation after calcination. The toxic metal ions are removed from aqueous solution by the anion exchange reaction in the pH region where toxic metal ions exist as the anionic species like AsO2-, HAsO42-,CrO42-, and SeO32-. The exchange amount is considerably concerned with the valence of anionic species and the size of anionic species. The removal of toxic metal ions were investigated from the engineering aspects such as the low concentration limit to be removed, the amount of hydrotalcite to be used for the perfect removal of toxic metal ions and so on.

Jan 1, 2006

By Wan Pu

Chrysotile asbestos samples from different mines have been studied by SEM and TEM, including high resolution electron microscopy, to find reasons for differences in physical properties of different types of asbestos fibres. The results show that the inner diameters of fibre tubes and the lattice images of fibres are different for soft and hard asbestos fibres. These differences are related to temperatures and geochemical conditions during the growth of chrysotile asbestos.

Jan 1, 1989

By Robert W. Bartlett

"Economic and other factors, mostly outside of metallurgy, that strongly influence applied research, development and especially successful commercial adoption of new processes for producing primary metals and other commodity materials are reviewed. These factors, which can be both positive and negative in their influence, are often too lightly regarded in the research planning stage. They include continuing imperatives that have long influenced new process development as well as more recent trends. Both are discussed. Nearly all new materials eventually become commodities--products made to standard specifications with no producer control over price. Success requires being a low cost producer on a world wide basis. Composites and other complex material assemblages are unlikely to escape this fate as they mature.INTRODUCTIONThe adoption of new processes, beginning with research and development, for primary metals and other commodity materials is particularly difficult because each new process must supplant an existing process that is already being used commercially. There are many requirements besides technical innovation and cost superiority that must be met by the new process. Consequently, few innovations make it all the way from the research laboratory to commercial success.This paper discusses some of the factors that influence success in developing new processes for primary metals and commodity materials, based on the authors experience as a research metallurgist and industrial research manager. It begins with some of the factors that are always present and constrain successful process research and development, and proceeds to current trends that are expected to continue long enough to influence processes in the year 2000. Many of these trends are contradictory in their effect on new process development, and the future remains uncertain.The prevailing importance of these trends will vary with the material, process concept and other factors intrinsic to each case. Nevertheless, an awareness of these influences can help to avoid some of the R&D pitfalls and dead ends. Such awareness is deemed to be a necessary condition to avoid failure when commercial adoption of a new process is the goal."

Jan 1, 1988