Iron Ores In China Research Articles

Occurrence characteristics and enrichment mechanism of cobalt in pyrite from the Han‐Xing type skarn iron deposit using laser‐ablation inductively‐coupled‐plasma mass‐spectrometry elemental mapping, Taihang Mountain, China

Cobalt is a critical and strategic metal mainly found as associated element in several types of deposits, of which skarn‐type deposits are the major sources. Han‐Xing type skarn iron deposit, having high grade iron ore and associated cobalt, is a typical skarn‐type iron ore in China. But the complete recovery and exploitation of cobalt are restricted because of the lower grade of related cobalt and the dearth of prior research on its occurrence condition and enrichment mechanism. In this paper, pyrite from five typical ore deposits in the Han‐Xing area was studied by using electron probe microanalysis (EPMA) and laser‐ablation inductively‐coupled‐plasma mass‐spectrometry (LA–ICP–MS) techniques to decipher the occurrence state and enrichment mechanism of associated cobalt in skarn‐type iron deposits. The results show that Co2+ replaces Fe2+ in pyrite through isomorphism. The distribution of cobalt in pyrite from different deposits varies greatly, that is, in the Xishimen iron deposit, the cobalt content is comparatively enriched in the pyrite's core. In contrast, in other deposits, the cobalt content is concentrated in the pyrite's rims, where it can be up to 1000 times higher than in the core. The cobalt mineralization in Han‐Xing area can be divided into several stages. The sulphur element of sulphide is mainly derived from evaporite, while cobalt mineralization occurred in the early stage with pyrite formation or in the late stage by metasomatism/cementation of Co‐rich ore‐forming fluid. The magma assimilated with the Ordovician evaporite not only promoted iron mineralization, but also became the main controlling factor for cobalt enrichment.

Preparation of high-purity magnetite from iron ore concentrate

In pursuit of environmental protection and green, low-carbon economic development, China has proposed the dual-carbon strategies of carbon peak and carbon neutrality. To achieve the dual-carbon goals, traditional steel metallurgical production processes are gradually shifting towards green and low-carbon hydrogen metallurgical processes. However, hydrogen metallurgical processes have strict requirements for raw materials and typically require the utilization of high-grade iron concentrates. The scarcity of high-grade iron ore in China severely constrains the development of hydrogen metallurgical processes. Therefore, this study proposes the utilization of ordinary magnetite concentrate to produce high-grade magnetite. Comprehensive analytical methods, including chemical analysis, X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD) analysis, laser particle size testing, optical microscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and mineral liberation analysis, were employed to elucidate the mineralogical characteristics of the iron concentrate. The analysis revealed that the iron concentrate had a total iron (TFe) grade of 65.56 %, with SiO2 and Al2O3 contents of 8.28 % and 0.38 %, respectively. Subsequently, a combined beneficiation process involving magnetic separation, flotation, and chemical leaching was conducted. Experimental results showed that a single magnetic separation obtained an iron concentrate grade of 67.52 % with an overall recovery of 86.18 %. Following magnetic separation, flotation was conducted to increase the concentrate grade. With one roughing and four cleaning flotation stages, a concentrate grade of 72.19 % and a 36.36 % overall recovery were achieved. A subsequent leaching operation after flotation yielded high-purity magnetite with a Fe grade of 72.30 % and an overall recovery of 35.68 %. The high-purity magnetite was confirmed to have a purity of up to 99.9 % based on chemical titration, XRD analysis, magnetic susceptibility measurement, and SEM analysis. Furthermore, detailed kinetics studies on leaching were conducted to elucidate the reaction mechanism, revealing an apparent activation energy of 25.70 kJ/mol. The successful implementation of this process will provide a benchmark for producing similar high-purity magnetite concentrates and contribute to China’s dual-carbon goals.

Efficient recovery of iron and chromium from laterite residue by non-molten metallization reduction

Laterite residues are good iron-bearing resources to decrease the external dependence on iron ores in China. At present, laterite residues are deposited in the land or transported to deep sea, which causes serious resource waste and environmental pollution. In order to utilize laterite residues efficiently and ease shortages of iron ores, non-molten metallization reduction was proposed to treat laterite residue. The thermodynamic and equilibrium analysis were studied to analyze the transformation mechanism and predict the optimal condition of the technology. The optimal conditions for non-molten metallization reduction are as follows: anthracite dosage is 30%, roasting time is 60 min and roasting temperature is 1200 °C. In the experimental results, the content of iron and chromium in the final concentrate is 88.64% and 1.45%, respectively. The reduction, migration and aggregation of calcines were researched to study the phase transformations and microstructural evolutions of the roasting process.

Superimposed zinc and gold mineralization in the Dunde iron deposit, western Tianshan, NW China: Constraints from LA-ICP-MS fluid inclusion microanalysis

The submarine volcanogenic iron oxide (SVIO) deposits are one of the most important sources of high-grade iron ores in China. Many large- and medium-scale SVIO deposits were recently discovered in the Awulale metallogenic belt (AMB) in Western Tianshan, NW China. The Dunde deposit in the AMB is a unique iron deposit containing large-scale Zn and medium-scale Au resources. The zinc mineralization in this deposit is generally located at the margin of iron orebodies constituting composite iron-zinc orebodies. To clarify the genetic relation between iron and Zn with Au mineralization, we conducted a detailed investigation of sphalerite-hosted fluid inclusions in the Dunde deposit. The primary fluid inclusions in sphalerite are liquid-rich, with homogenization temperature in the range of 189–219 ℃, and salinity of 19.68–22.38 wt% NaCl equiv. Single fluid inclusion LA-ICP-MS analysis suggests a magmatic source for the fluid as reflected by high Rb/Na (0.001–0.016), K/Na (0.18–0.83) and low Ca/K (1.03–9.38) ratios, which are distinctly different from those of basinal brines. The Cs/(K + Na + Ca)*10000 values (6.0–13.4) of sphalerite-hosted fluid inclusions are equivalent to those in porphyry-type Cu-Mo deposit (4.7–23.8), indicating that the ore-forming fluid originated from a highly evolved granitic magma, rather than intermediate-mafic magmatism related to iron mineralization. Thus, we propose that the zinc and gold mineralization in the Dunde deposit might be products of superimposed mineralization on iron orebodies during hydrothermal alteration related to granitic intrusions.

The high-grade Fe skarn deposit of Jinling, North China Craton: Insights into hydrothermal iron mineralization

Skarn-type Fe deposits constitute a major source of iron in the world, and 57% of the high-grade iron ores in China are hosted by skarn deposits. Most researchers agree that skarn-type Fe deposits are genetically linked with the associated magmas and precipitate from hydrothermal fluids, however, whether these ore-forming fluids are mainly derived from magmas or some other external sources is controversial. Besides, the detailed process of iron concentration in the high-grade ores in skarn Fe deposits has not been well constrained. To better understand these issues, we investigated the petrological, mineral chemical, geochronological, fluid inclusion and oxygen isotope characteristics of the Jinling Fe deposit, which is a typical high-grade skarn-type Fe deposit in the North China Craton. Zircon grains in these skarns were demonstrated to result from completely modification of magmatic zircons by the later hydrothermal fluids and they yield a weighted mean 206Pb/238U age of 126.7 ± 2.0 Ma (2σ) constraining the timing of the skarn iron formation, which is consistent with that of the ore-hosting Jinling complex. The similarity in chondrite-normalized REE patterns of the zircons in skarns and magmatic zircons suggests that the ore-forming hydrothermal fluids might mainly be derived from magmas. Additionally, the oxygen isotopes of the hydrothermal fluids in various stages as estimated based on δ18O values of representative hydrothermal minerals show relatively constant values during the evolution of hydrothermal system, suggesting that there was no significant involvement of external fluids. Three types of fluid inclusions, namely, high-salinity Type 1 with daughter minerals (homogenizing into liquid phase, with salinity of 42–71 wt% NaCl equivalent), vapor-rich Type 2 (homogenizing into vapor, with salinity ≤23 wt% NaCl equivalent), and relatively low-salinity Type 3 (homogenizing into liquid, with salinity ≤23 wt% NaCl equivalent) were identified in the various skarn minerals (garnet, clinopyroxene, epidote, and anhydrite). Among these, only Type 3 fluid inclusions occur in the clinopyroxene within the dominant massive ores, implying that the relatively low-salinity fluids were the predominant ore-forming hydrothermal fluids from which the magnetite ores precipitated. The high-salinity Type 1 fluids which might have resulted from phase separation (or boiling) of the primary magmatic hydrothermal fluids due to pressure drop, were believed to be responsible for the Fe-rich rims of zoned clinopyroxenes (with Fe-poor cores) in the thin magnetite-clinopyroxene interbedding layers between skarns and the massive magnetite orebodies. Thus, this zoned texture also implies an Fe re-enrichment event after formation of magnetite ores. The process of multiple Fe enrichment may significantly contribute to the formation of high-grade skarn-type Fe deposits.

Iron recovery from refractory limonite ore using suspension magnetization roasting: A pilot-scale study

Limonite ore is a potentially important iron resource and widely distributed in the world. However, it is difficult to process by traditional methods due to the high water content and fine dissemination of aluminum and silica. In this paper, typical refractory limonite ore was studied by suspension magnetization roasting and magnetic separation technology. According to the pilot-scale study, optimum roasting conditions were determined as a capacity of 120 kg/h, CO dosage of 6.5 m3/h, N2 dosage of 9.5 m3/h, roasting temperature of 460 °C, and gas flow of 16.0 m3/h. An iron concentrate with Fe grade of 64.97% and recovery of 94.53% was obtained using a suspension magnetization roasting – grinding – magnetic separation process. The material and roasted products were characterized by X-ray diffraction (XRD), mineral liberation analyzer (MLA), and backscattered electron (BSE) analyses. The results indicated that the iron oxide phase transformation was as follows goethite → hematite → magnetite → maghemite. The mineral dissemination analysis showed that fine grinding and magnetic separation was favorable to improve the quality of iron concentrates. However, some Al and Si were difficult to remove due to the isomorphism. The suspension magnetization roasting is feasible in economic terms, and the cost of magnetization roasting is $8 per ton. This technology will not only increase the available iron ore resource reserves but also alleviate the imbalance between supply and demand of iron ore in China.

An Experimental Research on Cationic Reverse Flotation of Anshan-Type Iron Ores

The mineral processing technology of Anshan-type iron ores has been developed in a rapid speed in recent years, and the combined flowsheet at the core of anionic reverse flotation has become a mainstream in the beneficiation of Anshan-type iron ores in china. With the successful application of this combined flowsheet, some obvious problems are also emerging. Such as high requirement of pulp temperature, complex reagent system, high cost of reagent consumption and so on. In view of this,we have carried out an experimental study on the separation of Anshan type iron ore by cationic reverse flotation . A new collector (named KBD) which is mixed amines have been developed . On this basis, the actual mineral separation experiment is carried out in the laboratory.With KBD as the collector,and starch and sodium hexametaphoshate as the depressant, has resulted in an iron concentrate of 68.16% and recovery rate of 89.71%. The determination of the electrokinetic potential and the infra-red spectroscopic analysis show that KBD can effectively and priorly adsorbed to the surface of quartz, and has greatly change the elecrtokinetic potential of quartz.The interaction of the depressing agent has increased the differences of the floatabilities in quartz and hermitite and changed the surface electric property so that the effective separation has been realized.

Transfer Mechanism of Lanthanum from Rare Earth Containing Iron Ore to Pig Iron during the Blast Furnace Process

Some iron ores are enriched with lanthanum element, for example, the Bayan Obo iron ore in China. The pig iron which used the Bayan Obo iron ore as the raw material was obtained from the blast furnace of Baotou Steel in order to research the transfer mechanisms of lanthanum from rare earth containing iron ore to pig iron during the blast furnace process. The thermodynamic process was calculated using the molecular-ion coexistence model. The slag-metal reactions of the hearth were carried out in the tube furnace. The morphology and phase structure in the pig iron were observed by SEM and XRD. The rule of lanthanum transfer was analyzed by physical and chemical analyses using ICP-MS. Fourier-transform infrared spectroscopy was used for analyzing the vibrations of functional groups. The results indicate that the La2O3 in the slag was reduced to LaC2 by carbon and then the LaC2 dissolved into the molten iron to form La. At last, coke which has the oxygen-containing functional groups (C-OH, C=O, and C-O-C) has capacity to absorb lanthanum that is dissolved in the molten iron during the blast furnace iron-making process, and increasing the lanthanum content in the slag leads to higher lanthanum concentration in the porous graphite phase of the pig iron. The coke is graphitized during the process and could remain in the pig iron as porous graphite phase which acts as the carrier of lanthanum.

Fluidized bed roasting technology in iron ores dressing in China: A review on equipment development and application prospect

Due to the undesirable characteristics of iron ore resources in China, it is necessary to utilize refractory iron ores resources with high efficiency. The mining and mineral processing costs are usually high. The supply of domestic iron ores in China has been in serious shortage for a long time. Therefore, the development and utilization of complex and refractory iron ore resources are extremely urgent. Magnetizing roasting followed by magnetic separation is an important method for the beneficiation of low grade iron ores. More attention has been paid to fluidized bed magnetizing roasting rather than shaft furnace and rotary kiln roasting in recent years. In this paper, the main characteristics of fluidized bed magnetizing roasting technology and the development process of its application in the beneficiation of refractory iron ores are introduced. The research status of several typical fluidized bed roasting processes and equipment in China are also summarized. Moreover, the application prospect of the technology for efficient utilization of low grade hematite, siderite, and limonite ores, as well as iron containing tailings, is analyzed.

The Influence of Iron Ore Tax on China's Metallurgical Mines

Mining industry is a very important industry in China. Its tax and fee policy is related to the whole industry. This paper summarizes the main types of taxes and fees involved in iron ore in China, Australia, Russia, Cameroon, Brazil, India and South Africa, and also compare the comprehensive tax and fee burden rates of iron ore companies in China with those of four major international mining companies, Rio Tinto, BHP Billiton, Valley and FMG. It concludes that the comprehensive tax and fee burden rates of iron ore companies in China are higher about 6% than those of the four major international mining companies. The main reasons for the increase are unreasonable industrial orientation of mining industry, high resource tax and value-added tax rates, few deductible items of value-added tax, and unreasonable collection of local special taxes and fees. Finally the author puts forward five suggestions on how to reduce the tax burden of iron ore companies. First, the government can improve the tax system and form a scientific, reasonable tax system. The second is adjusting the mining industry from the second industry to the primary industry. The third is to formulate a national strategy to ensure the safety of iron ore supply. The fourth is to uniformly determine the collection standard of resource tax rate by the country, cancel the unreasonable tax and fee collected by local government. The fifth is to increase fuel tax credits for mining companies.

Enhancing the Reduction of High-Aluminum Iron Ore by Synergistic Reducing with High-Manganese Iron Ore

How to utilize low grade complex iron resources is an issue that has attracted much attention due to the continuous and huge consumption of iron ores in China. High-aluminum iron ore is a refractory resource and is difficult to upgrade by separating iron and alumina. An innovative technology involving synergistic reducing and synergistic smelting a high-aluminum iron ore containing 41.92% Fetotal, 13.74% Al2O3, and 13.96% SiO2 with a high-manganese iron ore assaying 9.24% Mntotal is proposed. The synergistic reduction process is presented and its enhancing mechanism is discussed. The results show that the generation of hercynite (FeAl2O4) and fayalite (Fe2SiO4) leads to a low metallization degree of 66.49% of the high-aluminum iron ore. Over 90% of the metallization degree is obtained by synergistic reducing with 60% of the high-manganese iron ore. The mechanism of synergistic reduction can be described as follows: MnO from the high-manganese ore chemically combines with Fe2SiO4 and FeAl2O4 to generate Mn2SiO4, MnAl2O4 and FeO, resulting in higher activity of FeO, which can be reduced to Fe in a CO atmosphere. The main products of the synergistic reduction process consist of Fe, Mn2SiO4, and MnAl2O4.

Selective Liberation of High-Phosphorous Oolitic Hematite Assisted by Microwave Processing and Acid Leaching

The release of valuable minerals from the associated gangues is called liberation. Good liberation is essential to the subsequent separation stage. Selective liberation is advantageous to improve the degree of liberation. Oolitic hematite is one of the typical refractory iron ores in China, and its resources are abundant. However, owing to its fine dissemination and complex mineralogical texture, the conventional grinding processes are inefficient in improving the selective liberation of oolitic hematite. In this study, microwave processing and acid leaching were used to assist the liberation of oolitic hematite. The assisted liberation of the oolitic hematite mechanisms of microwave processing and acid leaching were studied by using scanning electron microscope (SEM), X-ray diffraction (XRD), BET specific surface area detection method (BET) and the transflective microscope method. The results indicated that microwave processing can reduce the mechanical strength of oolitic hematite and improve the liberation of hematite, and acid leaching can improve the microwave-assisted liberation efficiency and reduce the content of phosphorus in the grinding product. Compared to direct grinding, the liberation of hematite increased by 54.80% in the grinding product, and especially, the fractions of −0.038-mm and 0.05–0.074 mm increased significantly; however, there was no obvious change in other grain sizes, and the dephosphorization ratio reached 47.20% after microwave processing and acid leaching. After the two stages, the iron grade and recovery of the magnetic separation product increased by 14.26% and 34.62%, respectively, and the dephosphorization ratio reached 88.59%. It is demonstrated that microwave processing and acid leaching comprise an efficient method to improve the liberation of hematite and the dephosphorization ratio of oolitic hematite. The two-stage treatment can achieve selective liberation of oolitic hematite, which is beneficial to the following magnetic separation.

Occurrence of the Iron–rich Melt in the Heijianshan Iron Deposit, Eastern Tianshan, NW China: Insights into the Origin of Volcanic Rock–hosted Iron Deposits

AbstractLong‐standing controversy persists over the presence and role of iron–rich melts in the formation of volcanic rock‐hosted iron deposits. Conjugate iron–rich and silica–rich melt inclusions observed in thin‐sections are considered as direct evidence for the presence of iron‐rich melt, yet unequivocal outcrop‐scale evidence of iron‐rich melts are still lacking in volcanic rock‐hosted iron deposits. Submarine volcanic rock‐hosted iron deposits, which are mainly distributed in the western and eastern Tianshan Mountains in Xinjiang, are important resources of iron ores in China, but it remains unclear whether iron‐rich melts have played a role in the mineralization of such iron ores. In this study, we observed abundant iron‐rich agglomerates in the brecciated andesite lava of the Heijianshan submarine volcanic rock–hosted iron deposit, Eastern Tianshan, China. The iron‐rich agglomerates occur as irregular and angular masses filling fractures of the host brecciated andesite lava. They show concentric potassic alteration with silicification or epidotization rims, indicative of their formation after the wall rocks. The iron‐rich agglomerates have porphyritic and hyalopilitic textures, and locally display chilled margins in the contact zone with the host rocks. These features cannot be explained by hydrothermal replacement of wall rocks (brecciated andesite lava) which is free of vesicle and amygdale, rather they indicate direct crystallization of the iron‐rich agglomerates from iron‐rich melts. We propose that the iron‐rich agglomerates were formed by open‐space filling of volatile‐rich iron‐rich melt in fractures of the brecciated andesite lava. The iron‐rich agglomerates are compositionally similar to the wall‐rock brecciated andesite lava, but have much larger variation. Based on mineral assemblages, the iron‐rich agglomerates are subdivided into five types, i.e., albite‐magnetite type, albite‐K‐feldspar‐magnetite type, K‐feldspar–magnetite type, epidote‐magnetite type and quartz‐magnetite type, representing that products formed at different stages during the evolution of a magmatic‐hydrothermal system. The albite‐magnetite type represents the earliest crystallization product from a residual iron‐rich melt; the albite‐K‐feldspar‐magnetite and K‐feldspar‐magnetite types show features of magmatic‐hydrothermal transition, whereas the epidote‐magnetite and quartz‐magnetite types represent products of hydrothermal alteration. The occurrence of iron‐rich agglomerates provides macroscopic evidence for the presence of iron‐rich melts in the mineralization of the Heijianshan iron deposit. It also indicates that iron mineralization of submarine volcanic rock‐hosted iron deposits is genetically related to hydrothermal fluids derived from iron‐rich melts.

In situ LA‐ICP‐MS trace element analysis of magnetite from the late Neoarchean Gongchangling BIFs, NE China: Constraints on the genesis of high‐grade iron ore

The Precambrian banded iron formations (BIFs) not only relate to the evolution of life, ocean, and atmosphere but also provide important reserves of iron around the world. The Gongchangling iron ore deposit located in the Anshan‐Benxi area of Liaoning Province, China, is oxide facies Algoma‐type BIFs, and the Gongchangling No.2 mining area is famous for the production of high‐grade iron ore in China. Magnetite is the main ore mineral in the Gongchangling iron ore deposit, and the magnetite mainly exhibits three modes of occurrence: BIFs (without actinolite), actinolite‐bearing BIFs, and high‐grade iron ore. Trace elemental compositions of the magnetite with different occurrences of the Gongchangling iron ore deposit were obtained by laser ablation inductively coupled plasma mass spectrometry to constrain the genesis of the high‐grade iron ore. The magnetite from actinolite‐bearing BIFs shows relatively lower contents of Mg, Al, Mn, and Zn compared to the magnetite from BIFs (without actinolite), suggesting that coexisting minerals have played an important role in the trace element concentration in magnetite. The magnetite from high‐grade iron ore has lower contents of Ti and V and higher contents of Al and Mn than counterpart from BIFs (with/without actinolite), indicating that the high‐grade iron ore may be reformed by high temperature metamorphic hydrothermal fluid. The staurolite‐garnet‐biotite schist is the wall‐rock of high‐grade iron ore, and the garnet‐biotite geothermometry is used to evaluate the metamorphic temperature of 593 ± 17 °C. It is proposed that the metamorphic hydrothermal fluid produced during regional metamorphism reformed BIFs to generate high‐grade iron ore.

Investigation of the world trends of the development of seaports

The world trends of the development of seaports in recent years are investigated in the article. During the last twenty years, the volume of world seaborne trade has doubled, especially in the sectors of dry cargo and container traffic. This is due to the increase in trade in the southern hemisphere and the continued strong demand for iron ore in China. In terms of regional influence, Asia continues to dominate as the primary transshipment site, then follow North and South America, Europe, Oceania and Africa. The fall in oil prices has affected the volume of supply and sea trade, in particular the tanker trade, its share fell to 28.7 percent in 2014. Meanwhile, lower fuel costs make it possible to reduce the costs of ship operators and the rates paid by the shipper. This in turn could stimulate demand for maritime transportation services and the increase in marine cargo flow. The research allowed to identify macro factors that have a significant effect on the activity of the enterprises of the maritime industry (economic, political, technological) and to recommend the development directions for each group. Most of Ukrainian sea ports problems are systemic and interrelated and require settlement at the national level through the creation of an appropriate regulatory framework and the formation of the conceptual foundations on combination of government regulation and market self-regulation of sea ports development. Capacity building and improving the quality of works and port services is the main direction of investment and innovation activity. All this will lead to an increase in the competitiveness of Ukrainian ports in the world market due to increased volumes of cargo handling, attraction of new cargo flows and expansion of the range of work and services.

Upgrading of High-Aluminum Hematite-Limonite Ore by High Temperature Reduction-Wet Magnetic Separation Process

The huge consumption of iron ores in China has attracted much attention to utilizing low grade complex iron resources, such as high-aluminum hematite-limonite ore, which is a refractory resource and difficult to upgrade by traditional physical concentration processes due to the superfine size and close dissemination of iron minerals with gangue minerals. An innovative technology for a high temperature reduction-magnetic separation process was studied to upgrade a high-aluminum iron ore assaying 41.92% Fetotal, 13.74% Al2O3 and 13.96% SiO2. The optimized results show that the final metal iron powder, assaying 90.46% Fetotal, was manufactured at an overall iron recovery of 90.25% under conditions as follows: balling the high aluminum iron ore with 15% coal blended and at 0.3 basicity, reducing the dried pellets at 1350 °C for 25 min with a total C/Fe mass ratio of 1.0, grinding the reduced pellets up to 95%, passing at 0.074 mm and magnetically separating the ground product in a Davis Tube at a 0.10-T magnetic field intensity. The metal iron powder can be used as the burden for an electric arc furnace (EAF). Meanwhile, the nonmagnetic tailing is suitable to produce ceramic, which mainly consists of anorthite and corundum. An efficient way has been found to utilize high-aluminum iron resources.

Influencing factors analysis of China’s iron import price: Based on quantile regression model

When encountering high import prices and price volatility, China does not have the power to affect prices, although China has ranked first in iron ore imports since 2003. The existing literature usually investigates the impact factors of iron ore prices using the averaging method. It is difficult to depict the detailed impact of various factors on prices accurately. To provide sounder basis for the Chinese government to enact policy, this paper develops a quantile regression model with the lagged variables to measure factors that affect the import prices of iron ore in China under high, medium and low price levels. The analysis uses monthly data through January 2003 to March 2015. The results indicate that the effect intensity of the factors on the prices are various under different quantiles. As prices rise, the degree of positive influence of previous period of crude steel production on iron ore prices is gradually decreasing; conversely, the strength of previous period of import volume’s negative effect on prices is falling. Furthermore, it verifies that China has no voice in the international iron ore market. In low quantile, the strength of effect of prior period iron ore volume on prices is higher than that of China’s production of iron ore on import prices because the grade of China's iron ore resources is low. Therefore, when the iron ore prices are at a low quantile, China should expand the import of iron ore appropriately and reduce the exploitation of low-grade iron ore resources. Additionally, China should optimize crude steel output and actively invest in overseas iron ore exploration and mining to reduce the effect of prices fluctuations by reducing the dependence on imported iron ore. China may also promote the development of an international iron ore futures market and innovate iron ore business models to hedge foreign exchange risks because of the US dollar index has greatest negative effect on the prices.

A system analysis of the development strategy of iron ore in China

This paper aims to present a full picture of the current status and future trends of China's iron ore development using system analysis on the iron supply chain. First, we map China's iron flow to present the physical patterns of iron ore supply and demand in China. Next, the historical and future trends of iron ore development in China are discussed from four aspects including demand, resource availability, technology improvement, and strategy and policy. Based on these aspects, we conclude how to sustainably obtain overseas iron ore resources at a reasonable price as the key issue, and this issue is further analyzed from perspectives of market structure, the pricing mechanism, and Chinese steel companies’ behavior. In conclusion, we determined China must enhance cooperation with the main global suppliers, expand overseas investments effectively, and enhance domestic coordination to secure the import of resources and reduce price fluctuations.

Iron-rich fragments in the Yamansu iron deposit, Xinjiang, NW China: Constraints on metallogenesis

Volcanic rock-hosted iron deposits are among the important iron ores in China. However, the nature of primary magma and petrogenesis associated with these iron ores remains controversial. Here, we report iron-rich fragments (IRF) from the Yamansu iron deposit in Eastern Tianshan Mountains, NW China, which occurs in association with volcanic breccia, submarine volcanic breccia and ignimbrite. The IRF is composed of five types including oligoclase-iron oxide type (OIO), oligoclase-albite-iron oxide type (OAIO), albite-iron oxide type (AIO), albite-K-feldspar-iron oxide type (AKIO) and K-feldspar-iron oxide type (KIO). These fragments display typical volcanic fabric features, such as porphyritic texture, hyalopilitic texture of the groundmass and vesicles filled by minerals to form amygdales. The feldspar phenocrysts of IRF are dominantly albite. The groundmass of IRF consists of magnetite and feldspar. The magnetite is distributed in between the feldspar laths, and together display hyalopilitic texture which could be observed only in volcanic rocks. The vesicles are filled with magnetite, feldspar, chlorite and calcite from the margin to the interior. The IRF has high Si, Al, Fe, Ca, Ti, Na and K contents and low Mg content. The average total Fe is 26wt.%. The magnetite is mostly titanium–vanadium magnetite, with the TiO2 content ranging up to 4.86wt.% and V2O3 content up to 3.20wt.%. The IRF probably came from iron-rich melts and represent the products of the Fenner magma evolution. The basaltic magma evolved into the Fe–Na-rich residual melts by crystallization under low oxygen fugacity condition in a closed magma chamber after intruding into the shallow crust. The Fe–Na-rich residual melts were emplaced in hypabyssal environments or erupted generating the orebodies or providing the material source for the generation of the high-grade iron ores which were subsequently enriched by the late-stage hydrothermal fluids.

Biomass Reduction Roasting-Magnetic Separation of Low Grade Goethite

The average grade of iron ores in China is around 32%, about 10% lower than the world’s average level. In order to alleviate the demand of iron ore for steelmaking industries, it is urgent to develop a highly efficient, energy-saving, low-carbon and environment-friendly technology. The goethite ore from Northern Hainan Island was studied via reduction magnetization by pine, rice chaff, and corn straw biomass fuels. The magnetic properties and magnetic separation were discussed by optimizing the parameters of roasting temperature, roasting time, and the ratio of biomass fuels. The results show that we could obtain concentrated iron ore grade of pine roasting and magnetic separation grade of iron concentrate 61.64% with the recovery of 79.75% via pine fuel roasting, 61.75% with the recovery 80.16% via rice chaff, and 61.47% with the recovery of 81.28% via corn straw roasting. Thereby, we could deduce that biomass fuels for reduction roasting of low goethite ore is promising to substitute the traditional coal and coke fossil fuels.