By Taylor, P R; Shuey, S A; Vidal, E E; Gomez, J C
Many technologies exist for the treatment of titaniferous magnetites that contain vanadium. Each process is designed based on the relative amounts of titanium, vanadium and iron. In some cases, steelmaking is the primary purpose followed by the secondary recovery of vanadium. In others, the vanadium is the main product. This paper presents a review of these technologies
Key words: Vanadium, Titaniferous magnetites
In modem society, vanadium is defined as a strategic metal. Some 90% of the vanadium consumed globally is for use as an alloying agent for carbon steels, tool steels and high-strength, low-alloy steels (particularly for pipelines). Advanced titanium-aluminum- vanadium alloys are seeing application in the aerospace industry. Small, but ever growing amounts, are finding application as catalysts or in electronics. New uses are continually being discovered for this metal. One example of a new application is the vanadium-redox battery for use in generation plants and back-up power sources.
Vanadium is found in a large number of minerals, of which the most important are carnotite, roscoelite, vanadinite, mottramite and patronite. A little more than a third of the world’s vanadium is produced as a primary product; the balance is produced as byproducts of the iron and steel, oil refining, power generation and uranium enrichment industries. Vanadium can also be sourced by recycling spent catalysts from the petrochemical industry and ash produced by the combustion of oil emulsion in power stations. However, recycling activities are believed to account for only a small amount of total world supply. Vanadium is recovered from these ores largely as vanadium pentoxide (V^sub 2^O^sub 5^) (Perron, 2001).
Major sources of vanadium-bearing magnetite ores are scattered throughout Australia, China, Russia and South Africa. Current estimates of the world’s proven and probable vanadium reserves are of the order of 41.3 Mt (Vanitec, 2004a, 2004b). According to the U.S. Geological Survey, current estimates of the world’s reserves stand at 13 Mt with a reserve base of 38 Mt. (Table 1) (U.S. Geological Survey, 2001-2005). Commercial vanadium-bearing titaniferous magnetite deposits can be found in Kachkanar, Russia; Pan Zhihua, China; Bushveld, South Africa; and Windimurra, Western Australia (Lazutkin et al., 2001). Other deposits have been found in New Zealand, Canada and India, as well as in other countries.
Vanadium consumption in the steel sector has increased some 7% per ton of steel during the last 10 years as new alloying applications have been found to improve steel’s strength-to-weight ratio. Future demand from the aerospace and nuclear industries for nonferrous vanadium alloys such as titanium and super-alloys is also likely to grow. Vanadium is usually added in the form of ferrovanadium, a vanadium-iron alloy. Vanadium compounds, especially the pentoxide form, are used in the ceramics, glass and dye industries, and they are also important as catalysts in the chemical industry.
While established approaches may be used at an industrial scale to treat vanadium-bearing titaniferous magnetite ores in several countries, new alternatives are being developed worldwide. This review will give a short overview of the treatment of vanadium- bearing titaniferous magnetite ores.
Vanadium can be recovered from titaniferous magnetite ore by either of two processes: precipitating a vanadium salt from a leach of a salt-roasted ore and precipitation from a leach of salt- roasted slag obtained after smelting the ore to make a vanadium bearing pig iron followed by an oxygen blow in a converter forming the vanadium-rich slag (Fischer, 1975).
Table 1 – World mine production, reserves and reserve base.
The smelting of titanomagnetite containing vanadium in conventional blast furnaces using traditional smelting techniques may cause serious problems (Brothers et al., 2002), which may be characterized by poor permeability of the burden column and lower smelting rates and difficulties with slag chemistry and fluidity (Diao, 1999). The development of titanium carbides and nitrides in the blast furnace slags leads to a dense slag with entrained iron, slag sediment in the furnace hearth, periodical “huge slag effusion” and “hot sticking” phenomena; and formation of foamed slag. These phenomena cause abnormal performance of the blast furnace and the breakdown of normal production procedures (Li et al., 1989; Qu, 1989; Wang et al., 1989, Zhao et al., 1989; Ma et al., 2000; Smirnov et al., 2001).
In light of the above factors, duplex processes are used in world and domestic metallurgy to convert vanadium pig iron into steel (Smirnov, 2000). The duplex process used at the Nizhniy Tagil combine in Russia consists of blowing the vanadium pig iron in a first converter without the addition of lime, conversion of as much vanadium as possible into a commercial slag containing ~10% vanadium and the production of a carbon-bearing semifinished product. The vanadium in such a slag is in the form of a trioxide, so that it is environmentally harmless and can be efficiently used for the production of V^sub 2^O^sub 5^. The carbon-bearing semifinished product is converted to steel in a second converter (with the addition of the necessary amount of lime and other slag-forming materials to ensure that the steel has a low content of harmful impurities – phosphorous and sulfur).
Successful use of the duplex process requires an additional converter, which lowers the productivity of the shop and increases conversion costs. However, it also makes it unnecessary to use large quantities of scrap metal, which can introduce undesirable impurities.
There are some others technologies that have been developed for magnetite ores with high titanium content. For example, in the treatment of a large part of the vanadium-bearing magnetite from South Africa, the iron is produced by a process involving the pre- reduction of the magnetite with powdered coal in a rotary kiln followed by reduction in a submerged arc electric furnace. Smelting reduction of titanium-bearing iron ore in blast furnaces has been practiced extensively in recent times in China and Russia. The iron sands of New Zealand are being processed through the normal direct reduction route using the rotary kiln process for reduction (Vanitec, 2004a, 2004b).
Research (Geyrhofer et al., 2003) has been performed to optimize the roasting process in the recovery of vanadium with a control concept based on a temperature controller, a chemistry controller and an overhead controller, which enables a high degree of automation for a roasting process in a multiple heart furnace. Accurate models of the chemical reaction kinetics (Voglauer, 2003) that describe the reaction rate of the vanadium roast and its derivation were considered. Validation of the process model showed good agreement of measurement and simulation data for the transport of mass and temperatures. The authors concluded that the resulting control concept was developed with much emphasis on robustness, and, therefore, it is well suited for industrial application.
Established treatment technologies
South Africa. South African titaniferous magnetites from the Bushveld Complex provide a potential source of titanium, vanadium and iron. These ores generally comprise a magnetite spinel in which titanium is present in solid solution as ilmenite or ulvospinel and vanadium is present in solid solution as the spinel structure coulsonite. The upper 1,750 m of layered basic rocks of the Bushveld Complex contain approximately 8% magnetite disseminated in gabbroic rocks, plus a further 20 m of pure magnetite distributed through in excess of 20 discrete magnetite layers. Chemically, it contains V^sub 2^O^sub 5^ and TiO^sub 2^; the former decreasing in amount upwards from approximately 2%, while the latter increases from about 12% to 20%. No discrete vanadium minerals are present, but vanadium occurs in solid solution in the magnetite (Cawthorn and Molyneux, 2003).
The titaniferous magnetites from the Bushveld Complex in South Africa are of economical importance and are being exploited. South Africa’s vanadium-bearing titanomagnetite ores are mostly processed by four companies (Perron, 2001): Highveld Steel and Vanadium Corp. (Highveld); Vametco Minerals Corp.; Transvaal Alloys Pty Ltd. ; and VanadiumTechnologies (Vantech). One South African processing technology is known as the Highveld Steel and Vanadium Corp. process (Gupta and Krishnamurthy, 1992; Highveld Steel, 2003). The average grade of the company’s vanadiferous magnetite is 54.3% Fe, 1.6% V^sub 2^O^sub 5^ and 14.2% TiO^sub 2^ (Wells, 2003). Owing to the high titanium content of the magnetite ore that Highveld receives from its Mapochs Mine, it cannot be smelted in the same way as more common iron ores in a conventional blast furnace, which relies on the presence of a large excess of carbon to reduce iron oxide to metallic iron.
Highveld’s method of smelting the magnetite ore involves a preliminary “pre-reduction” stage. In this process, the Bushveld titaniferous magnetite ore is concentrated in a series of crushing and magneticseparation steps. The magnetic particles are crushed and screened, before they go to the pelletizing plant. Coal, dolomite and quartz are added to the magnetite concentrate for charge to the pre-reduction rotary kiln. The addition of dolomite and quartz guarantees that the titania will be fluxed out into the slag.
Figure 1 – The Highveld Steel and Vanadium Process – Vanadium Products Flowsheet (Highveld Steel, 2003).
Figure 2 – Flow diagram of the South African vanadium industry (Republic of South Africa, 2001 ).
The kiln is heated by burning pulverized coal to a temperature of 1,140C. (The use of coal and not coke has the effect of lowering the power requirements of the smelting, resulting in a cheaper iron- making process.) The hot pre-reduced charge is placed in a submerged arc furnace and heated to 1,350C. Carbon is added to control fluidity and iron content in the slag. The titanium separates from the molten pig iron and forms a dense slag, which can be drawn off at the start of tapping.
The pig iron typically contains 3.5% C, 1.28% V, 0.25% Si, 0.16% Ti, 0.065% S and 0.075% P. The slag typically contains 0.9% V^sub 2^O^sub 5^, 20% TiO^sub 2^, 18% CaO, 17% MgO, 19% SiO^sub 2^ and 13% Al^sub 2^O^sub 3^. In Highveld’s steel plant the hot metal is agitated and oxygen-blown in shaking ladles to remove the vanadium. Scrap, iron ore, anthracite and iron rejects are added if necessary. The temperature is kept below 1,400C to ensure vanadium oxidation with a minimum of carbon withdrawal from the bath. The slag from the shaking-ladle, oxygen-blowing operation contains the bulk of the vanadium – typically about 12% to 16% (by weight) vanadium. The iron is then transferred to a BOF and the rich vanadium slag transferred to a slag pot for further treatment to extract the vanadium. Figure 1 (Highveld Steel, 2003) shows a flowsheet for this process.
High-grade vanadium pentoxide for the international market is produced by the Vanchem division. The flowsheet for recovery of vanadium is shown in Fig. 2 (Republic of South Africa, 2001). As seen, the recovery process involves the roasting of finely milled ore from the Mapochs mine with a sodium salt. The roasted calcine is leached with water to recover the vanadium, which is then precipitated with an ammonium salt. After ammonia removal the vanadium pentoxide is fused and the flakes are drummed.
In another process, the vanadium-bearing magnetite ore is subjected to conventional crushing, grinding and magnetic separation to produce a magnetite concentrate. The magnetite concentrate undergoes a conventional salt roast/leach/precipitation process to recover saleable vanadium pentoxide (V^sub 2^O^sub 5^). Most of the V^sub 2^O^sub 5^ produced in the future will be converted to ferrovanadium (FeV) alloy.
The vanadium production facilities at Rhovan consist of conventional vanadium pentoxide (V^sub 2^O^sub 5^) and ferrovanadium (FeV) plants (Wells, 2003). The latter entered commercial production in November 2000 with sales commencing in June 2001. Run-of-mine ore is crushed and conveyed to a 5-MW autogenous grinding mill fitted with a pebble crusher and operating in a closed circuit with cyclones. Magnetite is separated from the ground material in low- intensity magnetic separators, followed by regrinding in a ball mill and a second stage of magnetic separation. Magnetite concentrate is filtered and stockpiled under cover prior to being blended with sodium carbonate flux and roasted in a coal-fired kiln. The resulting calcine is conveyed to one of three leach dams that are used to recover the vanadium bearing solution. Barren solid residue is mechanically scraped from the dams and conveyed to the calcine stockpile. Silica is removed from the pregnant solution by addition of aluminum sulfate, followed by filtration. Ammonium metavanadate is precipitated from the clean pregnant solution by addition of ammonium sulfate and filtered. Ammonia is driven off in two electric kilns to form V^sub 2^O^sub 5^ powder that is then melted in an electric furnace to form V^sub 2^O^sub 5^ flakes. V^sub 2^O^sub 5^ flakes form the feed for the ferrovanadium process where V^sub 2^O^sub 5^ is reacted with aluminum, iron and lime in an exothermic process to produce FeV ingots and an alumina slag.
Russia. The Kachkanar Deposit has reserves of more than 9 Mt of titanomagnetites. Titanium-magnetite ore from the Kachkanarskoe deposit is utilized for steel manufacture. Russia’s sole producer of vanadium raw material is the Kachkanar iron ore mining complex in Sverdlovsk oblast in the Urals that mines titaniferous magnetite (Levine, 1996). Vanadium is produced from vanadium rich slag – a co- product of iron production at the Nizhny Tagil and Chusovoy metallurgical plants, also in the Urals (Nizhiny Tagil Iron and Steel Works, 2003). Nizhniy Tagil Iron and Steel Works (NTMK) is located in the city of Nizhniy Tagil in the Ural Mountains. NTMK is one of the world’s largest companies processing vanadium-enriched titaniferous ores with subsequent vanadium recovery in blast furnaces and oxygen converters. Raw materials for the blast furnaces are supplied from the Kachkanarskoe titaniferous ore deposit and Tagilo-Kushvinskaya group of loadstone deposits. The main iron ore suppliers of NTMK are Kachkanarsky mining and dressing complex (KGOK); Vysokogorsky mining and dressing complex (VGOK) and Goroblagodatskoye mining company (GBRU). Due to the low (less than 1%) vanadium content of these ores, the metallurgical plant finds it expedient to combine the recovery of vanadium with the normal metallurgical processing of these ores. In this case, vanadium is a byproduct of the metallurgical conversion.
Studies in this area were begun in Russia in 1925, and metallurgists had developed a blast-furnace smelting technology that entailed the production of vanadium pig iron and a titanium-bearing slag. The ore is first processed in blast furnaces for producing the vanadium-containing cast iron. NTMK’s blast furnaces are designed for making two types of iron: pig iron and ferro-vanadium. They have used a smelting technology for iron with low Si (0.15%), Ti (up to 0.20%) and high V (up to 0.55%) within high-capacity furnaces. Smelting the vanadium-containing steel is performed in a basic oxygen converter with the use of the cast iron.
The presence of titanium in iron ore leads to several problems. The problems can be solved using two basic oxygen converters. NTMK’s BOS offers a two-stage process of smelting resulting into micro- alloyed vanadium steel and commercial slag of 16% to 28% V^sub 2^O^sub 5^. The first basic oxygen converter is used for producing the semiproduct and vanadium-containing slag (Gavrilyuk, 1996; Smirnov, 2000, 2001). This involves blowing the vanadium pig iron in a first converter, without lime addition, to convert the maximum vanadium into a slag containing approximately 10% vanadium. Cooling of the bath with the addition of rolling scale encourages the vanadium to move from the metal to the slag phase. Vanadium transfer from metal into slag is 85%. The semifinished product is 3.0% C and 0.03% V and small amounts of Si, Mn, Ti, P and S. The vanadium in the slag from the first converter exists as a trioxide, which is environmentally benign. The second basic oxygen converter is used for producing high-quality steel. The flow sheet of NTMK’s duplex process is shown in Fig. 3.
The blast-furnace conversion of titanomagnetites in modern blast furnaces, larger than 1,000 m^sup 3^, is based on the smelting of prepared vanadium-bearing materials obtained from iron ore (up to 60% to 70% unfluxed oxidized Kachkanar pellets, high-basicity sinter from the Kachkanar Mining-Concentration Combine (KachGOK), sinter prepared from concentrate and vanadium-bearing wastes), the use of natural gas, oxygen and steam to regulate the combustion temperature (1,950 to 2,000C) and maintenance of the optimum slag regime. In the blast furnace-converters process, it is reported that about 20% of the vanadium present in the initial ore is lost. According to estimates, due to the multiple-stages of processing, only about 33% to 37% of the vanadium in the ore ends up in the steel. Therefore, an alternative process has been proposed to treat Russian vanadiferous magnetite ore.
Figure 3 – NTMK’s duplex process of treating vanadium-bearing pig iron (Nizhiny Tagil Iron & Steel Works, 2003).
The direct production of iron- and vanadium-bearing ore, proposed by Russian metallurgists, is based on the Midrex process (Lazutkin et al., 2001). According to the proposal, the process includes metallization in a shaft furnace (SF), EAF refining and treatment in a “special steel treatment unit” (STU). In this process, the vanadium is present in the form of an oxide in each operation, and it is reduced from the slag to the steel only in the final conversion. The recovery of vanadium reportedly may reach 85% based on test work from 1998. The average degree of metallization of the Kachkanar pellets was 92.2% with 78.8% Fe^sub total^, 1.93% C and 0.76% V^sub 2^O^sub 5^. The feasibility of recovering vanadium in the arc steelmaking furnaces from a metallized product obtained from the Kachkanar deposit was also conducted. With the addition of aluminum injected with argon, vanadium was reduced into steel. Thus, almost any grade of vanadium steel might be produced without the use of ferrovanadium. The highest degree of vanadium recovery obtained was 81% to 84%. The proposed process is still subject to commercial trials.
China. China ranks third in vanadium and titanium reserves in the world, right after Russia and South Africa. The Panzhihua area of Sichuan province in China possesses iron, vanadium, titanium, cobalt and nickel resources. The proven deposits of titanium and vanadium account for 35.17% and 11.6% of world total reserves, respectively. The major producer of vanadium-bearing titanomagnetite concentrate is \Panzhihua Iron and Steel Group Corp., followed by Chengde Iron and Steel Group Co. Ltd. Panzhihua developed ferrovanadium and titanium magnetite smelting technology using conventional blast furnaces with an atomized vanadium extraction process, and a process of extracting titanium from abandoned tailings and vanadium from steel slag.
Figure 4 – Processing vanadium-bearing titaniferous magnetite at Chengde China.
The typical iron ore in this region consists mainly of titanomagnetite (35.42%), ilmenite (12.73%), sulfides (2.16%) and gangue (49.68%). Magnetic separation produces a magnetite-rich concentrate, with approximately 45% of the iron reporting, and an ilmenite rich tailings. The process involves gravity separation, magnetic separation, flotation and electrostatic separation. The vanadium-bearing titaniferous magnetite ore in the Panzhihua area has an average composition of: 39.8% Fe^sub total^, 13.26% TiO^sub 2^,0.39% V^sub 2^O^sub 5^, 11.90% SiO^sub 2^, 6.54% Al^sub 2^O^sub 3^, 5.14% MgO, 3.06% CaO, 0.61% S, 0.021% CoO and 0.024% NiO. After dressing, the vanadium-bearing titaniferous magnetite concentrate contains 51.55% Fe^sub total^ (with 32.10% FeO), 12.74% TiO^sub 2^, 0.579% V^sub 2^O^sub 5^, 4.7% SiO^sub 2^, 4.58% Al^sub 2^O^sub 3^, 3.09% MgO, 1.43% CaO, 0.562% S and 0.025% P. The concentrate is processed in conventional blast furnaces.
High viscosity, foaming of slag and low porosity of the sinter during reduction are three major problems encountered while using conventional blast furnace operation to process vanadium-bearing titaniferous magnetite concentrate. By using a high basic sinter the problems associated with this feed into a conventional blast furnace can be overcome, according to Panzhihua’s practice. The blast furnace slag has a composition of 28.95% CaO, 25.28% SiO^sub 2^, 15.22% Al^sub 2^O^sub 3^, 0.22% V^sub 2^O^sub 5^, 7.22% MgO, 1.06% FeO and 22.20% TiO^sub 2^ with a basicity of 1.15. The pig iron produced has the composition 4.31% C, 0.10%Si, 1.17%Ti, 0.32% V, 0.066% P and 0.054% S.
The Chengde Iron and Steel Group Co. Ltd. in Hebei Province China also processes vanadium-bearing titaniferous magnetite ore. The flowchart of its process is shown in Fig. 4 (Zashu and Chushao, 1996; Wang et al., 1999; Chengde Iron & Steel Groups Co. Ltd, 2003).
A new process for utilization of vanadium-titanium magnetite is comprised of pelletization, selective reduction of pellets in a rotary kiln using a mixture of lignite and anthracite as reducing agents; melting of the reduced cinder in an electric furnace to separate the iron from vanadium and titanium bearing slags; and injection of Na^sub 2^CO^sub 3^ and Na^sub 2^SO^sub 4^ into the molten slag with oxygen as a carrier gas to recover vanadium. Vanadium and titanium are recovered as V^sub 2^O^sub 5^ and TiO^sub 2^. Vanadium recovery is reported to be over 85%.
Canada. A process was developed on a laboratory scale for the recovery of titanium, vanadium and iron from the vanadiumbearing titanomagnetite deposit at Pipestone Lake, Manitoba, through a combined pyro- and hydrometallurgical processing route (Jena et al., 1995). Theore (57.5% Fe, 0.66% V and 16.6% TiO^sub 2^) is subjected to selective reduction smelting with most of the iron reporting to the metal and the vanadium and titanium to the slag. Iron metal purities of 99% have been seen.
The slag contains from 9% to 35% FeO, 31% to 46% TiO^sub 2^ and 1.2% to 1.6% V. More than 98% of the titanium and vanadium reports to the slag. The slag is then roasted with soda ash at 950C and leached with water at 80C to recover vanadium. The leach residue is further treated with hydrochloric acid at 105C to upgrade TiO^sub 2^ content by removing residual Fe, Mg an Al. The final product contains 82.9% TiO^sub 2^, 1.5% FeO, 15.6% SiO^sub 2^, 2% Al^sub 2^O^sub 3^, 1% MgO and 0.3% CaO with overall titanium recovery above 90%.
Aprocess was designed by the Centre de Recherches Minerales (CRM) of Canada for processing Chibougamou titaniferous magnetite concentrate (Gupta and Krishnamurthy, 1992). The flowchart is shown in Fig. 5. The Chibougamou mineral contains 8.46% to 9.80% TiO^sub 2^, 0.48% to 0.57% V^sub 2^O^sub 5^ and 29.19% to 34.5% Fe. Metallurgical tests performed at a pilot plant in the 198Os produced a magnetic concentrate containing 9.11% TiO^sub 2^, 1.35% V^sub 2^O^sub 5^ and 60.8% Fe with recoveries of 83.84% V^sub 2^O^sub 5^ and 62.26% Fe. The ore is crushed and ground to -20 mesh prior to magnetic concentration. The concentrate is further ground to -325 mesh before carbon addition (0.26% by weight) and pelletizing. The charge is processed via EAF, producing a TiO^sub 2^-rich slag, containing most of the vanadium. The vanadium content in the pig iron is kept below 0.07%. The slag is treated for vanadium recovery.
New Zealand. A significant characteristic of New Zealand iron sand is its relatively high titanium content. A typical analysis of New Zealand concentrated titanomagnetite is 80% Fe3O4, 8% TiO^sub 2^, 4% Al^sub 2^O^sub 3^, 3.4% SiO^sub 2^, 3.0% MgO, 0.8% CaO, 0.6% V^sub 2^O^sub 5^, 0.6% MnO, 0.06% P and 0.004% S (Techhistory, 2003). Titanomagnetite iron sand placers form Quaternary onshore beach and dune deposits and offshore marine deposits along 480 km of coastline from Kaipara Harbor south to Wanganui on the west coast of the North Island. The total identified resource is more than 850 Mt of concentrate assaying 55% to 56% Fe, 7% to 9% TiO^sub 2^ and 0.3% to 0.4% V^sub 2^O^sub 5^. BHP New Zealand Steel Ltd. produces about 2.4 Mt/a of titanomagnetite concentrate from two mines south of Auckland. At Waikato North Head, south of Auckland, BHP produces 1.2 Mt/a of titanomagnetite concentrate. Mining of the deposit began in 1969 (New Zealand Ministry of Economic Development, 2003).
Direct reduction, combined with EAF and oxygen steel-making furnace smelting technology is used in New Zealand to process titanomagnetite-iron sand concentrate (Mare, 1997; Christie and Brathwaite, 2003; Techhistory, 2003). Rotary kilns are employed in a direct reduction process, in which hot sponge iron is produced. The hot sponge iron is then melted continuously in an electric arc furnace to produce pig iron, which is finally fed to oxygen steel- making furnace for further processing. Such technology is practiced by BHP New Zealand Steel Ltd.
The concentrate of Waikato North Head is slurried 18 km to the steel mill at Glenbrook, where it is blended with Huntly subbituminous coal in the ratio of about 1.8:1 and fed to multihearth furnaces in which the coal converts to char and the mix is dried and heated. The concentrate/char mix is then hot fed into direct reduction kilns to form sponge iron containing 70% Fe. The sponge iron is melted in electric resistance smelters for further reduction to produce molten pig iron. The pig iron is tapped into ladles for hot charging into the steel plant. Prior to steelmaking, vanadium slag is removed from the iron by injected gas agitation. A vanadium-rich slag is formed and separated as a valuable byproduct. Currently 12,000 t/a is produced and exported to China, representing 1% of the world’s vanadium production.
At Taharoa, iron sand is mined by dredging to produce concentrate averaging 40% titanomagnetite. Annual production has been about 1.4 Mt since the operation opened in 1972. The concentrate is slurried through a 3-km-long pipeline to an offshore loading facility for export, mainly to Japan, with small quantities to South Korea and China.
There has been no production of titanium oxide from New Zealand deposits. Recovery of titanium from the titaniumbearing slag produced by smelting of the Waikato North Head titanomagnetite iron sand is not currently economic.
Australia. Australia is an emerging producer of vanadium, with the development of the Windimurra project in Western Australia. The Windimurra ore body is the largest known vanadiferous deposit in the world. The Windimurra vanadium mines and associated infrastructure are situated some 600 km northeast of Perth in Western Australia. Mineralization is in the form of vanadiferous magnetite hosted in magnetite gabbros. Within the magnetite gabbros, vanadium is present in solid solution with iron within the lattice structure of magnetite crystals.
Vanadium content varies from 1.4% to 2.1 % V^sub 2^O^sub 5^ and averages 1.7% V^sub 2^O^sub 5^ in individual magnetite grains. The combined measured and indicated resources are reported to be 106.32 Mt at 0.47% V^sub 2^O^sub 5^ in oxidized and unoxidized material, including 68.98 Mt at 0.47% V^sub 2^O^sub 5^ in oxidized material and 37.34 Mt at 0.47% V^sub 2^O^sub 5^ in unoxidized material. The ore body will provide for a 21-year mine life, with the potential for 100 years of operation. It was reported that the Windimurra Vanadium Project may be the world’s largest primary producer of vanadium pentoxide. The Windimurra plant is closely allied to the Rhovan and Vantech operations in South Africa. Windimurra follows the standard vanadium pentoxide recovery route of a salt roast of an iron oxide concentrate followed by a water leach and subsequent precipitation of the insoluble ammonium metavanadate (AMV) in a crystalline form. The AMV is then heated to produce vanadium pentoxide, melted and solidified as flake prior to packaging (Fig. 6).
One reported advantage of the Windimurra salt-roast process is the utilization of natural gas, rather than coal, as the fuel source. The use of this clean controllable energy source not only ensures that optimum roasting conditions are maintained but also eliminates a major source of process impurities from coal ash (Roderick, 1998; Xstrata, 2003).
Figure 5 – Flowchart of the CRM Process (Gupta and Krishnamurthy, 1992).
Figure 6 – Flowchart of the Windimurra Process (Roderick, 1998; Xstrata, 2003).
Many different technologies exist for the treatment of titaniferous magnetites that containvanadium. Each process is designed based on the relative amounts of titanium, vanadium and iron. In some cases, steelmaking is the primary purpose followed by secondary recovery of vanadium. In others, the vanadium is the main product.
Preprint number 05-025, presented at the SME Annual Meeting, Feb. 28-March 2, 2005, Salt Lake City, Utah. Revised manuscript received and accepted for publication November 2005. Discussion of this peer- reviewed and approved paper is invited and must be submitted to SME Publications Dept. prior to Nov. 30, 2006. Copyright 2006, Society for Mining, Metallurgy, and Exploration, Inc.
Brothers, I.V., et al., 2002, “Albemarle Iron Works (1771-1772): Why did this operation fail?” Nuclear Instruments and Methods in Physics Research, Section B: Beam Interaction with Materials and Atoms, Vol.189, No.1-4, April, pp. 340-343.
Cawthorn, R.G., and Molyneux, T.G., 2003, “Vanadiferous magnetite deposits of the Bushveld Complex,” http://www.wits.ac.za/science/ geology/bush_mindepsa.htm.
Chengde Iron and Steel Group Co. Ltd, 2003, http:// www.xxft.com.cn/JSZG. H3.gif.
Christie, T., and Brathwaite, B., 2003, “Mineral Commodity Report 15 – Iron,” http://www.med.govt.nz/crown_minerals/minerals/docs/ nzmining/nzmining22.pdf.
Department of Minerals and Energy, Republic of South Africa, 2001, “Producers of Vanadium Products,” Ferrous Mineral Commodities Produced in the Republic of South Africa, http://www.dme.gov.za/ publications/pdf/project_research/minerals/d8_2001/d8_2001-04.pdf.
Diao, R., 1999, “New understanding about special problems of smelting vanadium-bearing titanomagnetite with blast furnace, ” Kang T’ieh/Iron and Steel, Peking, Vol. 34, No. 6, pp. 12-21.
Fischer, R.P., 1975, “Vanadium Resources in Titaniferous Magnetite Deposits,” Geological Survey Professional 926-B, United States Government Printing Office. Washington.
Gavrilyuk, G.G., et al., 1996, “News in science and technology – Smelting vanadium pig iron with unstable coke quality,” Metallurgist (USSR) (USA), Vol. 40, No. 12, pp. 231-234.
Geyrhofer, W., Voglauer, B., and Joergl, H.P., 2003, “Control of a roasting process for the recovery of vanadium,” Conf. Proc. CCA 2003, Istanbul.
Gupta, C.K., and Krishnamurthy, N., 1992, Extractive metallurgy of Vanadium-Process Metallurgy 8, the Netherlands, Elsevier Science Publishers B. V., pp. 287-294.
Highveld Steel, 2003, “Process Technology at Highveld Steel,” http://www. highveldsteel.co.za/Process_Tech/Files/ ProcessTechnologyDoc.htm.
Jena, B.C., et al., 1995, “Extraction of titanium, vanadium and iron from titanomagnetite deposits at Pipestone Lake, Manitoba, Canada,” Minerals Engineering, Vol. 8, No. 1-2, Jan.-Feb.
Lazutkin, S.E., et al., 2001, “Improving a technology for the direct production of iron and vanadium-bearing products based on the Midrex process,” Metallurgist, (USSR) (USA), Vol. 45, No. 9-10, Sep.- Oct., pp. 354-359.
Levine, R.M., 1996, “The Mineral Industry of Russia,” U.S. Geological Survey-Minerals Information-1996, pp. 12-13.
Li, D., et al., 1989, “Study on metallurgical process of vanadium- bearing titanomagnetite in Blast Furnace,” Proceedings of International Symposium on Exploitation and Utilization of Vanadium- Bearing nanomagnetite, Panzhihua, China, Nov. 14-16, pp. 261-267.
Ma, J., Sun, X., and Sheng, S., 2000, “Intensified smelting of vanadium and titanium magnetite in blast furnace,” Iron & Steel (China) (Chinese), Vol. 35, No. 1, Jan., pp. 4-8.
Mare, B.,1997, ” BHP Titanomagnetite Mining Operations,” New Zealand Mining, Vol. 22. July, http://www.med.govt.nz/ crown_minerals/minerals/docs/nzmining/nzmining22.pdf.
New Zealand Ministry of Economic Development, 2003, http:// www.med. govt.nz/crown_minerals/minerals/resources/sands.html, “Titanomagnetite iron sand.”
Nizhniy Tagil Iron and Steel Works, 2003, “Specialization,” (NTMK), http://www. ntmk.ru/en/manufacture/specialization.php.
Perron, L., 2001, “Vanadium,” Canadian Minerals Yearbook, Vol. 59, pp. 59.1-59.7.
Qu, J, 1989, “Metallurgical properties of BF slag at Panzhihua Iron & Steel Co.,” Proceedings of International Symposium on Exploitation and Utilization of Vanadium-Bearing Titanomagnetite, Panzhihua, China, Nov. 14-16, pp. 300-307.
Roderick, S., 1998, “Primary vanadium production-the Windimurra project,” Ryan’s Notes, Ferroalloys Conference, http:// www.pmal.com.au/Ferro98.html.
Smirnov, L.A, 2000, “Processing vanadium-bearing and titanomagnetite iron ore,” Metallurgist (USSR) (USA), Vol. 44, No. 5- 6, Jan., pp. 230-232.
Smirnov, L.A., et al., 2001, “Science, technology, industry- processing vanadium-bearing titanomagnetites at the Nizhniy Tagil Metallurgical Combine,” Metallurgist (USSR) (USA) Vol. 45, No. 5-6, pp. 232-234.
Techhistory, 2003, http://www.techhistory.co.nz/pages/ Processing.htm, “Process Options.”
U.S. Geological Survey, 2001-2005, Mineral Commodities Survey, Vanadium 2001-2005, http://minerals.usgs.gov/minerals/pubs/ commodity/vanadium/
Vanitec, 2004a, “Main deposits of vanadium,” http:// www.vanitec.org/e/s1b2p1le. htm.
Vanitec, 2004b, “Titaniferous magnetites,” http:// www.vanitec.org/e/s1b2p3le. htm.
Voglauer, B., Grausam, A., and Joergl, H.P., 2003, “Reaction- kinetics of the vanadium roast process using steel slag as a secondary raw material,” Conf. Proc. Processing & Disposal of Mineral Industry Waste’03, Falmouth, UK, June 18-20, 2003
Wang, S., et al., 1999, “The conductivity and the crystallization of perovskite (CaTiO^sub 3^) from Ti-bearing blast furnace slag studied by A.C. Impedance method,” ISIJ Int., Vol. 39, No. 11, pp. 1116-1119.
Wang, X., Yi, S., and Diao, R., 1989, “The BF practice of smelting vanadium-bearing titano-magnetite at Panzhihua Iron & Steel Co.,” Proceedings of International Symposium on Exploitation and Utilization of Vanadium-Bearing Titanomagnetite, Panzhihua, China, Nov. 14-16, pp. 63-72.
Wells, A.P., 2003, “Competent persons’ and technical reports – South African chrome and vanadium assets.”
Xstrata, 2003, http://www.xstrata.com/reports/doc/xtr- revolution09e_en.pdf, “Competent persons” and technical reports- Australian vanadium assets.”
Zhou, C., et al., 1989, “Smelting characteristic of Panzhihua’s vanadium-bearing titano-magnetite in Blast Furnace,” Proceedings of International Symposium on Exploitation and Utilization of Vanadium- Bearing Titanomagnetite, Panzhihua, China, Nov. 14-16, pp. 148-157.
Zushu, L., and Chushao, X., 1996, “The smelting process of titanium-silicon ferroalloy using blast furnace titaniferous slag,” ISIJ Int., Vol. 36, No. 3, pp. 279-283.
P.R. Taylor, S.A. Shuey, E.E. Vidal and J.C. Gomez
Professor, graduate student, assistant professor and graduate student, respectively, Colorado School of Mines, Golden, Colorado.
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