Iron ore processing for steel production is crucial to the development and economy of Mongolia. Regardless of having abundant natural resources and raw materials, Mongolia almost doesn’t produce final products. So fa...Iron ore processing for steel production is crucial to the development and economy of Mongolia. Regardless of having abundant natural resources and raw materials, Mongolia almost doesn’t produce final products. So far, most mining and mineral beneficiation plants export raw materials only subjected to beneficiation process. Out of more than 200 deposits in Mongolia, 91 deposits had been explored with different methods and stages, and estimated the resource of 33 reserves. Without processing the iron ore, it is impossible to use it for steelmaking due to its high sulfur and phosphorus impurities. Therefore, to study the processing of iron ore deposits in Mongolia, we did a preliminary investigation of iron ore deposits and took samples from the Tamir Gol deposit with high silica and phosphorus content that is difficult to process. Then, conducted mineral analysis and determined the grain structure and beneficiation characteristics of Tamir Gol iron deposit. .展开更多
The study was conducted to determine the applicability of gravity separation method on the Ashashire gold ore deposit Benishangul gumuz region, western Ethiopia. The Ashashire composite was produced to provide suffici...The study was conducted to determine the applicability of gravity separation method on the Ashashire gold ore deposit Benishangul gumuz region, western Ethiopia. The Ashashire composite was produced to provide sufficient mass for this study and experiment, including sample preparation, mineralogical analysis of gold and associated elements, gravity concentration, and data interpretation and analysis. During the study, a grind optimization was conducted on the composites sample with varying grind size to evaluate the effect of grind size on gold recovery. The ore was moderately ground to the standard grind size of 80%, passing 106 µm, 75 µm, 53 µm and this nominal size was selected for the preliminary assessment for concentration optimization for this deposit. The gravity testing comprised three-stage concentration using Knelson concentrator. High recovery of gold from the gravity concentrates was achieved from the second gravity concentration. Based on the laboratory experimental result analysis, a grind size of P80 75 µm is selected as optimal size for the Ashashire gold deposit. Increasing the grind size from P80 of 75 µm to 106 µm decreases the recovery rate from 75% to 54%, or decreasing the grind size from P80 of 75 µm to 53 µm decreases the gold recovery rate to 37%. The native gold grain in the ores is mostly associated with quartz and fine gold is closely associated with pyrite. According to analysis of the fire assay, chemical, and mineralogical data, only gold and telluride is commercially valuable elements in the ores. Predominantly gold was occurred in the native form of Au-Te. The sample subjected to gravity separation assayed about 2.6 g/t Au.展开更多
In this study, the theory of ore formation on the Earth and the Moon was developed. It is shown that ore deposits on the Earth and the Moon were mainly formed simultaneously with the separation of the Moon from the pr...In this study, the theory of ore formation on the Earth and the Moon was developed. It is shown that ore deposits on the Earth and the Moon were mainly formed simultaneously with the separation of the Moon from the protoplanet and the formation of the oldest continents. The formation of terrestrial ores occurred as a result of the release of intermediate and heavy chemical elements from the deep layers of the protoplanet and the subsequent process of adhesion to old terrestrial geological faults. The time of terrestrial and lunar ores formations corresponds to the boundary between the Tonian and Cryogenian Periods (~720 Ma). Lunar ore formation processes are different on the near and far sides. The farside of the Moon is a single piece of the protoplanetary lithosphere, so ores there could be formed mainly due to the overflow of igneous rocks over the edge of the lunar continent. On the nearside, due to the rapid cooling, ores were formed in the area of navel-string during the drip-liquid separation of the Moon from the Earth. Due to the fact that the Moon separated at the first stage, the amount of water and methane on it is limited. In periods after the Cryogenian, volcanic, lava and sedimentary rocks on Earth could be enriched with intermediate elements due to the disruption of vertical stratification during galactic storms. To analyze this, a comparison of terrestrial volcanic and lunar pseudo-volcanic activity was carried out in the work.展开更多
The skarn and ore bodies of the stratabound skarn copper deposits of Tongling, Anhui Province, are both controlled by definite stratigraphic horizons, and they are concordant with the strata. They occur as layers and ...The skarn and ore bodies of the stratabound skarn copper deposits of Tongling, Anhui Province, are both controlled by definite stratigraphic horizons, and they are concordant with the strata. They occur as layers and layer-like bodies in permeable carbonate rocks of the Middle-Upper Carboniferous Huanglong and Chuanshan Formations which are underlain by impermeable shale or siliceous rocks of the Upper Devonian Wutong Formation. The authors study the dynamics of ore-forming processes of the ore deposits with the dynamic model of coupled transport and reaction, and the following results are obtained: The salinity gradient and flow rate of the ore-forming fluids can both promote the mixing and reaction of juvenile water and formation water, and the permeable strata are favourable sites for the intense transport-reaction of mixing and the formation of deposits. (2) As isothermal transport-reaction took place along the bedding of strata, the moving transport-reaction front formed at the contact between the ore-forming fluids and the rocks advanced slowly along the permeable strata, and then stratiform skarn and ore bodies concordant with the strata were formed. (3) The gradient transport-reaction taking place across the isotherms in the cross-bedding direction caused the mineralogical composition to alter gradually from magnesian skarn to sulphide ore bodies.展开更多
This study focuses on experiments of Au and Cu dissolved in vapor phase in hydrothermal fluids. Experiments prove that Au and Cu can re-distribute in vapor phase and liquid phase during separation of Au- and Cu-bearin...This study focuses on experiments of Au and Cu dissolved in vapor phase in hydrothermal fluids. Experiments prove that Au and Cu can re-distribute in vapor phase and liquid phase during separation of Au- and Cu-bearing supercritical fluids to vapor and liquid phases. These experimental results can illustrate some ore geneses, where boiling phenomena of ore fluids were found. Au- and Cubearing NaHCO3-HCl solutions were heated up to more than 350℃ in the main vessel, and then passed through a phase separator in a temperature range from 250℃ to 300℃, separated into vapor and liquid phases. We collected and analyzed the liquid and vapor samples separately, and found that Au and Cu dissolved and distributed in vapor phase. In some cases, the concentrations of Au and Cu in vapor are higher than those in liquid phase. Those experiments are used to interpret field observations of fluid inclusion data of some Au and Cu deposits, and demonstrate that some Au and Cu ore deposits are derived from metals transportation in vapor phase.展开更多
The optimization system, which was the subject of our study, is an autonomous chain for the automatic management of cyanide consumption. It is in the phase of industrial automation which made it possible to use the ma...The optimization system, which was the subject of our study, is an autonomous chain for the automatic management of cyanide consumption. It is in the phase of industrial automation which made it possible to use the machines in order to reduce the workload of the worker while keeping a high productivity and a quality in great demand. Furthermore, the use of cyanide in leaching tanks is a necessity in the gold recovery process. This consumption of cyanide must be optimal in these tanks in order to have a good recovery while controlling the concentration of cyanide. Cyanide is one of the most expensive products for mining companies. On a completely different note, we see huge variations during the addition of cyanide. Following a recommendation from the metallurgical and operations teams, the control team carried out an analysis of the problem while proposing a solution to reduce the variability around plus or minus 10% of the addition setpoint through automation. It should be noted that this automatic optimization by monitoring the concentration of cyanide, made use of industrial automation which is a technique which ensures the operation of the ore processing chain without human intervention. In other words, it made it possible to substitute a machine for man. So, this leads us to conduct a study on concentration levels in the real world. The results show that the analysis of the modeling of the cyanide consumption optimization system is an appropriate solution to eradicate failures in the mineral processing chain. The trend curves demonstrate this resolution perfectly.展开更多
Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has rem...Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has remained a witness to a stable zone not affected by the ancient erosion process. BIFs are most abundant and are dated to the Neoarchaean and Late Kibalian, hosted in the Upper Congo Granites Massifs of the DR. Congo. Zatua Hills consist of dolerite, phyllade, clay-rich sediment, poor itabirite, enriched BIFs, friable hematite, hard hematite, and mineralized and unmineralized breccias. Field study and geochemistry analysis by XRF, XRD, and ICP-MS are executed in order to know the geochemistry signature and paragenesis of Zatua Hills and the probably process could lead the BIFs to iron ore. The geochemistry analysis by XRF, XRD, and ICP-MS shows that Iron ore content has an iron rate between 57% and 69% with less deleterious elements such as Si, P, and Al. These deleterious elements are secondary and have silicium composition (probably quartz or chert, goethite, and Kaolinite), aluminum (probably gibbsite, variscite, cadwaladérite, goethite, and Kaolinite), phosphorous (probably variscite), and hydrated minerals, which are grown LOI in the samples. Hypogen and supergen processes are played in BIFs for iron ore conversion and, respectively, silica dissolution and leaching. Metamorphism was also impacted and marked by the Ti element (anatase) in samples, contributing to the crystallization of martite to hematite after magnetite oxidation.展开更多
This study aims to characterize the different lithofacies of the Ct<sup>3</sup> formation in the Niamey region, and to determine the distribution of major and trace elements, in order to highlight the cond...This study aims to characterize the different lithofacies of the Ct<sup>3</sup> formation in the Niamey region, and to determine the distribution of major and trace elements, in order to highlight the conditions for the establishment of iron mineralization. A lithological column, synthesizing sections of selected outcrops in the vicinity of Niamey, was produced. The chemical compositions of the selected samples were determined by X-ray fluorescence (XRF) spectrometry. Microscopic analysis of the thin sections determined the gœthitic nature of the oolitic iron ore. The oolites show a quartz, limonitic or gœthitic nucleus. Sometimes the nucleus is absent. From a morphoscopic point of view, two types of oolites have been distinguished: spherical-shaped and ellipsoidal-shaped oolites. The oolites are either contiguous or disseminated, as the case may be, in a limonitic to goethitic cement or in a fine sandstone matrix. The larger oolites (pisolites) are relatively friable. They reflect the influence of a relatively turbulent to submerged environment. The hardground of the iron mineralized horizons are covered by quartz grains. They are indicative of a submerged or emergent environment. X-ray fluorescence analysis shows high Fe<sub>2</sub>O<sub>3</sub> contents<sub> </sub>(50% to 80%) and variable contents of major elements SiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub>, MnO, MgO, CaO, K<sub>2</sub>O and P<sub>2</sub>O<sub>5</sub> associated with certain trace elements such as Th, U, V, Y, Zn, Zr and As. The results of the study are an important tool for decision-makers to adopt effective prevention/remediation measures for groundwater contamination in the Continental terminal aquifer systems.展开更多
Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase min...Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase mineral exploration sites. The activity concentrations of natural radionuclides <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K in the soil samples received from bauxite and rutile mineral mining vicinities revealed high concentrations of <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K compared to the control soil samples sourced 500 m away from the mineral exploration vicinities. Radiological detriments RLI, AUI, Hin and Hex unveiled values exceeding the radiation standard concentration (>1) for soil. X-ray diffraction characterization of bauxite ore revealed the interlocking minerals of Bauxite (18)%, Albite (11)%, Garnet (15)%, Illite (6)% and Muscovite (43)% in various proportions obtained within the 2θ range (9.18 to 64.4) and a peak value (intensity, cps) of 3400. Pure bauxite percentage in the ore meets metallurgical grade (15 - 25)%. X-ray diffraction of rutile ore revealed the minerals of rutile (40)%, quartz (21.4)%, ilmenite (27)% and garnet (11.8)% found within the 2θ range (27.5 to 35.6) and a peak value intensity of 31.1 - 100.0 cps also meeting the metallurgical grade of 15% - 25%. The major environmental concern associated with the mineral-sands industry is the radiation hazards, pollution of ground-water sources from heavy metals, mineral transport with heavy equipment’s, dredging operations in fragile coastal area and clearing of vegetation.展开更多
The laboratories in the bauxite processing industry are always under a heavy workload of sample collection, analysis, and compilation of the results. After size reduction from grinding mills, the samples of bauxite ar...The laboratories in the bauxite processing industry are always under a heavy workload of sample collection, analysis, and compilation of the results. After size reduction from grinding mills, the samples of bauxite are collected after intervals of 3 to 4 hours. Large bauxite processing industries producing 1 million tons of pure aluminium can have three grinding mills. Thus, the total number of samples to be tested in one day reaches a figure of 18 to 24. The sample of bauxite ore coming from the grinding mill is tested for its particle size and composition. For testing the composition, the bauxite ore sample is first prepared by fusing it with X-ray flux. Then the sample is sent for X-ray fluorescence analysis. Afterwards, the crucibles are washed in ultrasonic baths to be used for the next testing. The whole procedure takes about 2 - 3 hours. With a large number of samples reaching the laboratory, the chances of error in composition analysis increase. In this study, we have used a composite sampling methodology to reduce the number of samples reaching the laboratory without compromising their validity. The results of the average composition of fifteen samples were measured against composite samples. The mean of difference was calculated. The standard deviation and paired t-test values were evaluated against predetermined critical values obtained using a two-tailed test. It was found from the results that paired test-t values were much lower than the critical values thus validating the composition attained through composite sampling. The composite sampling approach not only reduced the number of samples but also the chemicals used in the laboratory. The objective of improved analytical protocol to reduce the number of samples reaching the laboratory was successfully achieved without compromising the quality of analytical results.展开更多
Recently, a number of large molybdenum (-copper) deposits have been discovered successively in the Laba area, Shangri-La county, northwestern Yunnan province. The investigation confirmed that there is a superlarge por...Recently, a number of large molybdenum (-copper) deposits have been discovered successively in the Laba area, Shangri-La county, northwestern Yunnan province. The investigation confirmed that there is a superlarge porphyry-skarn hydrothermal vein type molybdenum-polymetallic- metallogenic system with the total prediction reservoir of more than 150 mt molybdenum. The porphyry intrusions contributed to the mineralization closely, the superficial little vein molybdenum (-copper, lead, silver) ore-bodies are usually located in faults and fractures, and the deep porphyry type ore-bodies occurred in the granodiorite porphyries, the skarn type ore-bodies occurred in the contact zone intrused into Triassic limestone or Permian basalts. Laba ore block is a new exploration area with great prospecting potential. In order to reduce the target area and guide the further exploration work, the magnetic method measurement about 3.3 square kilometres was carried out in the ore field. This paper presents an application of analyzing the horizontal and vertical derivative, using Fast Fourier Transform (FFT) filter (FFT high-pass, low-pass, cosine roll-off, suscepbility), calculated spectra frequency energy to predict the depth and intensity of the apparent remanence magnetization of source (Hilbert). The calculated results and magnetic anomalous show that the remanence anomaly is caused by the intrusions into the Triassic limestone and Permian basalts with small anomalies, and the depth of located source is not great. We have identified a number of positions to the three drilled well, the drilled result specify interpretation with very high accuracy. The magnetic method is helpful to identify porphyry mineralization, and judge the shape and depth of the concealed ore-bearing intrusive bodies under the similar geological condition.展开更多
Oolitic iron ore is one of the most important iron resources. This paper reports the recovery of iron from high phosphorus oolitic iron ore using coal-based reduction and magnetic separation. The influences of reducti...Oolitic iron ore is one of the most important iron resources. This paper reports the recovery of iron from high phosphorus oolitic iron ore using coal-based reduction and magnetic separation. The influences of reduction temperature, reduction time, C/O mole ratio, and CaO content on the metallization degree and iron recovery were investigated in detail. Experimental results show that reduced products with the metallization degree of 95.82% could be produced under the optimal conditions (i.e., reduction temperature, 1250℃; reduction time, 50 min; C/O mole ratio, 2.0; and CaO content, 10wt%). The magnetic concentrate containing 89.63wt% Fe with the iron recovery of 96.21% was obtained. According to the mineralogical and morphologic analysis, the iron minerals had been reduced and iron was mainly enriched into the metallic iron phase embedded in the slag matrix in the form of spherical particles. Apatite was also reduced to phosphorus, which partially migrated into the metallic iron phase.展开更多
Iron nugget and boron-rich slag can be obtained in a short time through high-temperature reduction of boron- bearing iron concentrate by carbonaceous material, both of which are agglomerated together as a carbon compo...Iron nugget and boron-rich slag can be obtained in a short time through high-temperature reduction of boron- bearing iron concentrate by carbonaceous material, both of which are agglomerated together as a carbon composite pellet. This is a novel flow sheet for the comprehensive utilization of boron-bearing iron concentrate to produce a new kind of man-made boron ore. The effect of reducing agent species (i.e., carbon species) on the reduction and melting process of the composite pellet was investigated at a laboratory scale in the present work. The results show that, the reduction rate of the composite pellet increases from bituminite, anthracite, to coke at temperatures ranging from 950 to 1300~C. Reduction temperature has an important effect on the microstructure of reduced pellets. Carbon species also affects the behavior of reduced metallic iron particles. The anthracite-bearing composite pellet melts faster than the bituminite- bearing composite pellet, and the coke-bearing composite pellet cannot melt due to the high fusion point of coke ash. With anthracite as the reducing agent, the recovery rates of iron and boron are 96.5% and 95.7%, respectively. This work can help us get a further understanding of the new process mechanism.展开更多
All the indium-rich deposits with indium contents in ores more than 100×10^-6 seems to be of cassiterite-sulfide deposits or Sn-bearing Pb-Zn deposits, e.g., in the Dachang Sn deposit in Guangxi, the Dulong Sn-Zn...All the indium-rich deposits with indium contents in ores more than 100×10^-6 seems to be of cassiterite-sulfide deposits or Sn-bearing Pb-Zn deposits, e.g., in the Dachang Sn deposit in Guangxi, the Dulong Sn-Zn deposit in Yunnan, and the Meng'entaolegai Ag-Pb-Zn deposit in Inner Mongolia, the indium contents in ores range from 98×10^-6 to 236×10^-6 and show a good positive correlation with contents of zinc and tin, and their correlation coefficients are 0.8781 and 0.7430, respectively. The indium contents from such Sn-poor deposits as the Fozichong Pb-Zn deposit in Guangxi and the Huanren Pb-Zn deposit in Liaoning are generally lower than 10×10^-6, i.e., whether tin is present or not in a deposit implies the enrichment extent of indium in ores. Whether the In enrichment itself in the ore -forming fluids or the ore-forming conditions has actually caused the enrichment/depletion of indium in the deposits? After studying the fluid inclusions in quartz crystallized at the main stage of mineralization of several In-rich and In-poor deposits in China, this paper analyzed the contents and studied the variation trend of In, Sn, Pb and Zn in the ore-forming fluids. The results show that the contents of lead and zinc in the ore-forming fluids of In-rich and -poor deposits are at the same level, and the lead contents range from 22×10^-6 to 81×10^-6 and zinc from 164×10^-6 to 309×10^-6, while the contents of indium and tin in the ore-forming fluids of In-rich deposits are far higher than those of Inpoor deposits, with a difference of 1-2 orders of magnitude. Indium and tin contents in ore-forming fluid of In-rich deposits are 1.9×10^-6-4.1×10^-6 and 7×10^-6-55×10^-6, and there is a very good positive correlation between the two elements, with a correlation coefficient of 0.9552. Indium and tin contents in ore-forming fluid of In-poor deposits are 0.03×10^-6-0.09×10^-6 and 0.4×10^-6-2.0×10^-6, respectively, and there is no apparent correlation between them. This indicates, on one hand, that In-rich oreforming fluids are the material basis for the formation of In-rich deposits, and, on the other hand, tin probably played a very important role in the transport and enrichment of indium.展开更多
The technology of direct reduction by adding sodium carbonate (Na2CO3) and magnetic separation was developed to treat Western Australian high phosphorus iron ore. The iron ore and reduced product were investigated b...The technology of direct reduction by adding sodium carbonate (Na2CO3) and magnetic separation was developed to treat Western Australian high phosphorus iron ore. The iron ore and reduced product were investigated by optical microscopy and scanning electron microscopy. It is found that phosphorus exists within limonite in the form of solid solution, which cannot be removed through traditional ways. During reduction roasting, Na2CO3 reacts with gangue minerals (SiO2 and A1203), forming aluminum silicate-containing phosphorus and damaging the ore structure, which promotes the separation between iron and phosphorus during magnetic separation. Meanwhile, Na2CO3 also improves the growth of iron grains, increasing the iron grade and iron recovery. The iron concentrate, assaying 94.12wt% Fe and 0.07wt% P at the iron recovery of 96.83% and the dephosphorization rate of 74.08%, is obtained under the optimum conditions. The final product (metal iron powder) after briquetting can be used as the burden for steelmaking by an alactrie a.re furnace to rer)la,ce scrar) steel.展开更多
文摘Iron ore processing for steel production is crucial to the development and economy of Mongolia. Regardless of having abundant natural resources and raw materials, Mongolia almost doesn’t produce final products. So far, most mining and mineral beneficiation plants export raw materials only subjected to beneficiation process. Out of more than 200 deposits in Mongolia, 91 deposits had been explored with different methods and stages, and estimated the resource of 33 reserves. Without processing the iron ore, it is impossible to use it for steelmaking due to its high sulfur and phosphorus impurities. Therefore, to study the processing of iron ore deposits in Mongolia, we did a preliminary investigation of iron ore deposits and took samples from the Tamir Gol deposit with high silica and phosphorus content that is difficult to process. Then, conducted mineral analysis and determined the grain structure and beneficiation characteristics of Tamir Gol iron deposit. .
文摘The study was conducted to determine the applicability of gravity separation method on the Ashashire gold ore deposit Benishangul gumuz region, western Ethiopia. The Ashashire composite was produced to provide sufficient mass for this study and experiment, including sample preparation, mineralogical analysis of gold and associated elements, gravity concentration, and data interpretation and analysis. During the study, a grind optimization was conducted on the composites sample with varying grind size to evaluate the effect of grind size on gold recovery. The ore was moderately ground to the standard grind size of 80%, passing 106 µm, 75 µm, 53 µm and this nominal size was selected for the preliminary assessment for concentration optimization for this deposit. The gravity testing comprised three-stage concentration using Knelson concentrator. High recovery of gold from the gravity concentrates was achieved from the second gravity concentration. Based on the laboratory experimental result analysis, a grind size of P80 75 µm is selected as optimal size for the Ashashire gold deposit. Increasing the grind size from P80 of 75 µm to 106 µm decreases the recovery rate from 75% to 54%, or decreasing the grind size from P80 of 75 µm to 53 µm decreases the gold recovery rate to 37%. The native gold grain in the ores is mostly associated with quartz and fine gold is closely associated with pyrite. According to analysis of the fire assay, chemical, and mineralogical data, only gold and telluride is commercially valuable elements in the ores. Predominantly gold was occurred in the native form of Au-Te. The sample subjected to gravity separation assayed about 2.6 g/t Au.
文摘In this study, the theory of ore formation on the Earth and the Moon was developed. It is shown that ore deposits on the Earth and the Moon were mainly formed simultaneously with the separation of the Moon from the protoplanet and the formation of the oldest continents. The formation of terrestrial ores occurred as a result of the release of intermediate and heavy chemical elements from the deep layers of the protoplanet and the subsequent process of adhesion to old terrestrial geological faults. The time of terrestrial and lunar ores formations corresponds to the boundary between the Tonian and Cryogenian Periods (~720 Ma). Lunar ore formation processes are different on the near and far sides. The farside of the Moon is a single piece of the protoplanetary lithosphere, so ores there could be formed mainly due to the overflow of igneous rocks over the edge of the lunar continent. On the nearside, due to the rapid cooling, ores were formed in the area of navel-string during the drip-liquid separation of the Moon from the Earth. Due to the fact that the Moon separated at the first stage, the amount of water and methane on it is limited. In periods after the Cryogenian, volcanic, lava and sedimentary rocks on Earth could be enriched with intermediate elements due to the disruption of vertical stratification during galactic storms. To analyze this, a comparison of terrestrial volcanic and lunar pseudo-volcanic activity was carried out in the work.
基金MGMR Eighth Five- Year Plan Basic Geology Research Foundation Grant 8502216China National Natural Science Foundation Grant 49173169
文摘The skarn and ore bodies of the stratabound skarn copper deposits of Tongling, Anhui Province, are both controlled by definite stratigraphic horizons, and they are concordant with the strata. They occur as layers and layer-like bodies in permeable carbonate rocks of the Middle-Upper Carboniferous Huanglong and Chuanshan Formations which are underlain by impermeable shale or siliceous rocks of the Upper Devonian Wutong Formation. The authors study the dynamics of ore-forming processes of the ore deposits with the dynamic model of coupled transport and reaction, and the following results are obtained: The salinity gradient and flow rate of the ore-forming fluids can both promote the mixing and reaction of juvenile water and formation water, and the permeable strata are favourable sites for the intense transport-reaction of mixing and the formation of deposits. (2) As isothermal transport-reaction took place along the bedding of strata, the moving transport-reaction front formed at the contact between the ore-forming fluids and the rocks advanced slowly along the permeable strata, and then stratiform skarn and ore bodies concordant with the strata were formed. (3) The gradient transport-reaction taking place across the isotherms in the cross-bedding direction caused the mineralogical composition to alter gradually from magnesian skarn to sulphide ore bodies.
文摘This study focuses on experiments of Au and Cu dissolved in vapor phase in hydrothermal fluids. Experiments prove that Au and Cu can re-distribute in vapor phase and liquid phase during separation of Au- and Cu-bearing supercritical fluids to vapor and liquid phases. These experimental results can illustrate some ore geneses, where boiling phenomena of ore fluids were found. Au- and Cubearing NaHCO3-HCl solutions were heated up to more than 350℃ in the main vessel, and then passed through a phase separator in a temperature range from 250℃ to 300℃, separated into vapor and liquid phases. We collected and analyzed the liquid and vapor samples separately, and found that Au and Cu dissolved and distributed in vapor phase. In some cases, the concentrations of Au and Cu in vapor are higher than those in liquid phase. Those experiments are used to interpret field observations of fluid inclusion data of some Au and Cu deposits, and demonstrate that some Au and Cu ore deposits are derived from metals transportation in vapor phase.
文摘The optimization system, which was the subject of our study, is an autonomous chain for the automatic management of cyanide consumption. It is in the phase of industrial automation which made it possible to use the machines in order to reduce the workload of the worker while keeping a high productivity and a quality in great demand. Furthermore, the use of cyanide in leaching tanks is a necessity in the gold recovery process. This consumption of cyanide must be optimal in these tanks in order to have a good recovery while controlling the concentration of cyanide. Cyanide is one of the most expensive products for mining companies. On a completely different note, we see huge variations during the addition of cyanide. Following a recommendation from the metallurgical and operations teams, the control team carried out an analysis of the problem while proposing a solution to reduce the variability around plus or minus 10% of the addition setpoint through automation. It should be noted that this automatic optimization by monitoring the concentration of cyanide, made use of industrial automation which is a technique which ensures the operation of the ore processing chain without human intervention. In other words, it made it possible to substitute a machine for man. So, this leads us to conduct a study on concentration levels in the real world. The results show that the analysis of the modeling of the cyanide consumption optimization system is an appropriate solution to eradicate failures in the mineral processing chain. The trend curves demonstrate this resolution perfectly.
文摘Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has remained a witness to a stable zone not affected by the ancient erosion process. BIFs are most abundant and are dated to the Neoarchaean and Late Kibalian, hosted in the Upper Congo Granites Massifs of the DR. Congo. Zatua Hills consist of dolerite, phyllade, clay-rich sediment, poor itabirite, enriched BIFs, friable hematite, hard hematite, and mineralized and unmineralized breccias. Field study and geochemistry analysis by XRF, XRD, and ICP-MS are executed in order to know the geochemistry signature and paragenesis of Zatua Hills and the probably process could lead the BIFs to iron ore. The geochemistry analysis by XRF, XRD, and ICP-MS shows that Iron ore content has an iron rate between 57% and 69% with less deleterious elements such as Si, P, and Al. These deleterious elements are secondary and have silicium composition (probably quartz or chert, goethite, and Kaolinite), aluminum (probably gibbsite, variscite, cadwaladérite, goethite, and Kaolinite), phosphorous (probably variscite), and hydrated minerals, which are grown LOI in the samples. Hypogen and supergen processes are played in BIFs for iron ore conversion and, respectively, silica dissolution and leaching. Metamorphism was also impacted and marked by the Ti element (anatase) in samples, contributing to the crystallization of martite to hematite after magnetite oxidation.
文摘This study aims to characterize the different lithofacies of the Ct<sup>3</sup> formation in the Niamey region, and to determine the distribution of major and trace elements, in order to highlight the conditions for the establishment of iron mineralization. A lithological column, synthesizing sections of selected outcrops in the vicinity of Niamey, was produced. The chemical compositions of the selected samples were determined by X-ray fluorescence (XRF) spectrometry. Microscopic analysis of the thin sections determined the gœthitic nature of the oolitic iron ore. The oolites show a quartz, limonitic or gœthitic nucleus. Sometimes the nucleus is absent. From a morphoscopic point of view, two types of oolites have been distinguished: spherical-shaped and ellipsoidal-shaped oolites. The oolites are either contiguous or disseminated, as the case may be, in a limonitic to goethitic cement or in a fine sandstone matrix. The larger oolites (pisolites) are relatively friable. They reflect the influence of a relatively turbulent to submerged environment. The hardground of the iron mineralized horizons are covered by quartz grains. They are indicative of a submerged or emergent environment. X-ray fluorescence analysis shows high Fe<sub>2</sub>O<sub>3</sub> contents<sub> </sub>(50% to 80%) and variable contents of major elements SiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub>, MnO, MgO, CaO, K<sub>2</sub>O and P<sub>2</sub>O<sub>5</sub> associated with certain trace elements such as Th, U, V, Y, Zn, Zr and As. The results of the study are an important tool for decision-makers to adopt effective prevention/remediation measures for groundwater contamination in the Continental terminal aquifer systems.
文摘Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase mineral exploration sites. The activity concentrations of natural radionuclides <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K in the soil samples received from bauxite and rutile mineral mining vicinities revealed high concentrations of <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K compared to the control soil samples sourced 500 m away from the mineral exploration vicinities. Radiological detriments RLI, AUI, Hin and Hex unveiled values exceeding the radiation standard concentration (>1) for soil. X-ray diffraction characterization of bauxite ore revealed the interlocking minerals of Bauxite (18)%, Albite (11)%, Garnet (15)%, Illite (6)% and Muscovite (43)% in various proportions obtained within the 2θ range (9.18 to 64.4) and a peak value (intensity, cps) of 3400. Pure bauxite percentage in the ore meets metallurgical grade (15 - 25)%. X-ray diffraction of rutile ore revealed the minerals of rutile (40)%, quartz (21.4)%, ilmenite (27)% and garnet (11.8)% found within the 2θ range (27.5 to 35.6) and a peak value intensity of 31.1 - 100.0 cps also meeting the metallurgical grade of 15% - 25%. The major environmental concern associated with the mineral-sands industry is the radiation hazards, pollution of ground-water sources from heavy metals, mineral transport with heavy equipment’s, dredging operations in fragile coastal area and clearing of vegetation.
文摘The laboratories in the bauxite processing industry are always under a heavy workload of sample collection, analysis, and compilation of the results. After size reduction from grinding mills, the samples of bauxite are collected after intervals of 3 to 4 hours. Large bauxite processing industries producing 1 million tons of pure aluminium can have three grinding mills. Thus, the total number of samples to be tested in one day reaches a figure of 18 to 24. The sample of bauxite ore coming from the grinding mill is tested for its particle size and composition. For testing the composition, the bauxite ore sample is first prepared by fusing it with X-ray flux. Then the sample is sent for X-ray fluorescence analysis. Afterwards, the crucibles are washed in ultrasonic baths to be used for the next testing. The whole procedure takes about 2 - 3 hours. With a large number of samples reaching the laboratory, the chances of error in composition analysis increase. In this study, we have used a composite sampling methodology to reduce the number of samples reaching the laboratory without compromising their validity. The results of the average composition of fifteen samples were measured against composite samples. The mean of difference was calculated. The standard deviation and paired t-test values were evaluated against predetermined critical values obtained using a two-tailed test. It was found from the results that paired test-t values were much lower than the critical values thus validating the composition attained through composite sampling. The composite sampling approach not only reduced the number of samples but also the chemicals used in the laboratory. The objective of improved analytical protocol to reduce the number of samples reaching the laboratory was successfully achieved without compromising the quality of analytical results.
文摘Recently, a number of large molybdenum (-copper) deposits have been discovered successively in the Laba area, Shangri-La county, northwestern Yunnan province. The investigation confirmed that there is a superlarge porphyry-skarn hydrothermal vein type molybdenum-polymetallic- metallogenic system with the total prediction reservoir of more than 150 mt molybdenum. The porphyry intrusions contributed to the mineralization closely, the superficial little vein molybdenum (-copper, lead, silver) ore-bodies are usually located in faults and fractures, and the deep porphyry type ore-bodies occurred in the granodiorite porphyries, the skarn type ore-bodies occurred in the contact zone intrused into Triassic limestone or Permian basalts. Laba ore block is a new exploration area with great prospecting potential. In order to reduce the target area and guide the further exploration work, the magnetic method measurement about 3.3 square kilometres was carried out in the ore field. This paper presents an application of analyzing the horizontal and vertical derivative, using Fast Fourier Transform (FFT) filter (FFT high-pass, low-pass, cosine roll-off, suscepbility), calculated spectra frequency energy to predict the depth and intensity of the apparent remanence magnetization of source (Hilbert). The calculated results and magnetic anomalous show that the remanence anomaly is caused by the intrusions into the Triassic limestone and Permian basalts with small anomalies, and the depth of located source is not great. We have identified a number of positions to the three drilled well, the drilled result specify interpretation with very high accuracy. The magnetic method is helpful to identify porphyry mineralization, and judge the shape and depth of the concealed ore-bearing intrusive bodies under the similar geological condition.
基金supported by the National Natural Science Foundation of China(Nos.51134002 and 51074036)
文摘Oolitic iron ore is one of the most important iron resources. This paper reports the recovery of iron from high phosphorus oolitic iron ore using coal-based reduction and magnetic separation. The influences of reduction temperature, reduction time, C/O mole ratio, and CaO content on the metallization degree and iron recovery were investigated in detail. Experimental results show that reduced products with the metallization degree of 95.82% could be produced under the optimal conditions (i.e., reduction temperature, 1250℃; reduction time, 50 min; C/O mole ratio, 2.0; and CaO content, 10wt%). The magnetic concentrate containing 89.63wt% Fe with the iron recovery of 96.21% was obtained. According to the mineralogical and morphologic analysis, the iron minerals had been reduced and iron was mainly enriched into the metallic iron phase embedded in the slag matrix in the form of spherical particles. Apatite was also reduced to phosphorus, which partially migrated into the metallic iron phase.
基金support by the National Natural Science Foundation of China(No.51274033)
文摘Iron nugget and boron-rich slag can be obtained in a short time through high-temperature reduction of boron- bearing iron concentrate by carbonaceous material, both of which are agglomerated together as a carbon composite pellet. This is a novel flow sheet for the comprehensive utilization of boron-bearing iron concentrate to produce a new kind of man-made boron ore. The effect of reducing agent species (i.e., carbon species) on the reduction and melting process of the composite pellet was investigated at a laboratory scale in the present work. The results show that, the reduction rate of the composite pellet increases from bituminite, anthracite, to coke at temperatures ranging from 950 to 1300~C. Reduction temperature has an important effect on the microstructure of reduced pellets. Carbon species also affects the behavior of reduced metallic iron particles. The anthracite-bearing composite pellet melts faster than the bituminite- bearing composite pellet, and the coke-bearing composite pellet cannot melt due to the high fusion point of coke ash. With anthracite as the reducing agent, the recovery rates of iron and boron are 96.5% and 95.7%, respectively. This work can help us get a further understanding of the new process mechanism.
基金the Key 0rientation Research Project of the Chinese Academy of Sciences (KZCX2-YW- 111);the National Natural Science Foundation of China (Grant Nos. 40172037 and 40072036) for its financial support.
文摘All the indium-rich deposits with indium contents in ores more than 100×10^-6 seems to be of cassiterite-sulfide deposits or Sn-bearing Pb-Zn deposits, e.g., in the Dachang Sn deposit in Guangxi, the Dulong Sn-Zn deposit in Yunnan, and the Meng'entaolegai Ag-Pb-Zn deposit in Inner Mongolia, the indium contents in ores range from 98×10^-6 to 236×10^-6 and show a good positive correlation with contents of zinc and tin, and their correlation coefficients are 0.8781 and 0.7430, respectively. The indium contents from such Sn-poor deposits as the Fozichong Pb-Zn deposit in Guangxi and the Huanren Pb-Zn deposit in Liaoning are generally lower than 10×10^-6, i.e., whether tin is present or not in a deposit implies the enrichment extent of indium in ores. Whether the In enrichment itself in the ore -forming fluids or the ore-forming conditions has actually caused the enrichment/depletion of indium in the deposits? After studying the fluid inclusions in quartz crystallized at the main stage of mineralization of several In-rich and In-poor deposits in China, this paper analyzed the contents and studied the variation trend of In, Sn, Pb and Zn in the ore-forming fluids. The results show that the contents of lead and zinc in the ore-forming fluids of In-rich and -poor deposits are at the same level, and the lead contents range from 22×10^-6 to 81×10^-6 and zinc from 164×10^-6 to 309×10^-6, while the contents of indium and tin in the ore-forming fluids of In-rich deposits are far higher than those of Inpoor deposits, with a difference of 1-2 orders of magnitude. Indium and tin contents in ore-forming fluid of In-rich deposits are 1.9×10^-6-4.1×10^-6 and 7×10^-6-55×10^-6, and there is a very good positive correlation between the two elements, with a correlation coefficient of 0.9552. Indium and tin contents in ore-forming fluid of In-poor deposits are 0.03×10^-6-0.09×10^-6 and 0.4×10^-6-2.0×10^-6, respectively, and there is no apparent correlation between them. This indicates, on one hand, that In-rich oreforming fluids are the material basis for the formation of In-rich deposits, and, on the other hand, tin probably played a very important role in the transport and enrichment of indium.
基金support by China Scholarship Council(No.201206370127)support from CSIRO,Australia
文摘The technology of direct reduction by adding sodium carbonate (Na2CO3) and magnetic separation was developed to treat Western Australian high phosphorus iron ore. The iron ore and reduced product were investigated by optical microscopy and scanning electron microscopy. It is found that phosphorus exists within limonite in the form of solid solution, which cannot be removed through traditional ways. During reduction roasting, Na2CO3 reacts with gangue minerals (SiO2 and A1203), forming aluminum silicate-containing phosphorus and damaging the ore structure, which promotes the separation between iron and phosphorus during magnetic separation. Meanwhile, Na2CO3 also improves the growth of iron grains, increasing the iron grade and iron recovery. The iron concentrate, assaying 94.12wt% Fe and 0.07wt% P at the iron recovery of 96.83% and the dephosphorization rate of 74.08%, is obtained under the optimum conditions. The final product (metal iron powder) after briquetting can be used as the burden for steelmaking by an alactrie a.re furnace to rer)la,ce scrar) steel.