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By Ming-Feng Ye, Jun Wang, Guang-liang Wu

In order to reduce the Al2O3 inclusions in 50Cr5MoV roller steel produced by EBT-LF-VD-VC process in a steelmaking plant, the LF refining slag was optimized and the influence of optimized slags with different w(CaO)/w(Al2O3) ratios on reducing inclusions were investigated in the laboratory. The results showed that, when w(CaO) = 50–55%, w(Al2O3) = 25–30% and w(CaO)/w(Al2O3) = 1.5–2.0, this optimized slag can not only reduce massive Al2O3 come from aluminium deoxidation, but also change the remain into plastic CaO-MgO-Al2O3 spherical compound inclusions with 1–5 lm diameter, the harm on the performance of the steel was minimized.

Mar 1, 2018

By Yuanbo Zhang, Zhixiong You, FENG ZHOU, Guanghui Li, Zhengwei Yu, Zhiwei Peng

Reduction disintegration of sinter significantly affects the coke consumption and productivity of blast furnace smelting. As we know, the reduction disintegration index (RDI+3.15) of sinter obtained from titanomagnetite concentrate is relatively worse than those from ordinary iron ores. In this study, the effect of sintering parameters, mainly involving coke breeze dosage and basicity on sintering indexes was investigated using titanomagnetite concentrate as raw material in an experimental-scale pot. Subsequently, RDI+3.15 of the sinter was detected according to the Chinese standard of GB/T13242-91. The results show that RDI+3.15 rises with the increase of coke breeze dosage, while it decreases with increasing basicity from 0.5 to 2.0 and then increases in the basicity range of 2.0-3.0. Finally, the microstructure of sinter before and after reduction was studied. And the mechanism of reduction disintegration was preliminary revealed by analyzing the morphologies and distributions of minerals in the sinter.

Jan 1, 2015

By Fengyu Ren, Kunpeng Yu, Gideon Chitomb, Qiangqiang Gao, Liqiang Ma, Jiangtao Zhai, Ichhuy Ngo

The penetration of rock fragments of overlying strata causes advanced ore dilution during drawing. The results of numerical and physical experiments showed that the proposed numerical simulation was applicable and the microscopic parameters of the model were reliable. The penetration under the variables of particle diameter ratio, density ratio, overlying strata thickness, and particle morphology was clarified. The penetration was quantitatively characterized by the discharge amount and the dilution rate. The experimental results showed that the diameter ratio and density ratio had a significant influence on the penetration. On the irregular shape of particles, the penetration is weakened. The overlying strata thickness had little effect on the penetration. This study could provide a theoretical basis for the full section uniform drawing, avoiding advanced ore dilution and further optimization of recovery rate.

Nov 13, 2023

By Qi Shifu, Guo Tao, Liu Haoquan, Yao Chaogui, Zheng Li

Abstract: To excavate oil-gas pipeline ditches in a rocky region or area the explosive method is needed. When a parallel ditch is to be dug by blasting near or in the vicinity of an existing pipeline, a safe criterion must be determined to ensure safety for the latter. In this investigation, with the construction of the second phase of the West-East Gas Pipeline Project, we carried out real blasting tests and numerical simulations to explore the safety criteria for the existing pipeline. Through this investigation, we obtained the safe strain elasticity threshold es2000µe, blast vibration velocity calculation formula, and the maximum vibration velocity Vmax=14cm/s(5.51in./s) for the pipe under blast shock loading, and worked out how to determine the charge size in the follow-up blasting excavation. These results can be used to determine the maximum explosive weight per delay and decide delays for the initiation circuit network in blasting a parallel pipeline ditch, and to make safety assessments for the existing pipeline in service. Having successfully been applied in the second and third phases of the West-East Gas Pipeline Project, China-Russia Oil Pipeline Project and China-Myanmar Gas Pipeline Project, these findings are very significant for other similar pipeline construction.

Jan 1, 2014

Study on Selective Reduction and Magnetic Separation of Low-Grade Nickel Laterite Ore to Produce High Nickel Concentrate

Sep 13, 2010

By Hongyang Cao

The iron constituents selectively separated from the modified copper slags by magnetic separation and flotation.were studied. The results of magnetic separation for modified copper smelting slags show that the grinding size, current intensity and dispersant agent had great influence on grade, and recovery ratio of TFe in preparation concentrate; The results of flotation for magnetic concentrate show that the positive flotation of sodium oleate negatively upgrade the grade of magnetic concentrate, but the reverse flotation of lauryl amine and soluble starch are effective. The grade of TFe can reach 54% and the recovery ratio can reach about 90% in magnetic concentrate, when the grinding size is 45.8µm and the current intensity is 2.5A. The optimal effect is obtained by using lauryl amine as collector and soluble starch as depressant to reverse flotate magnetic concentrate, and the grade of TFe is upgraded 2.37%.

Jan 1, 2009

By Y. G. Sun

This paper mainly reported separation manganese silver oxidized ores process by amylum de-gradation reduction and its influencing factors. When dosage is given according to nMn : nH2SO4 : n(C6H10O5)n : nH2O=1:k21.8: k116.66:30, the amount of up to 95.93% Mn leach rate and less than 2% silver loss can be obtained. Cyanidation process was used to extracted silver from leaching Mn residues. Silver leach rate could reach 94.15% at consumed amount of 1kg/t NaCN for 1h. Silver leach recovery rate was more than 92.27% by leaching Mn and cyanidation two-step processes so manganese and silver were separated effectively.

Jan 1, 2014

By Fang Liu, Xin Tan, Zhong-ming Wang, Yan-bo Shang, Jie Zhao

"The flotation separation of sulphides bulk concentrate containing Cu, Zn, Mo and Bi, which was obtained by both table-flotation of gross sand of gravity separation of wolframite and bulk flotation of wolframite slimes using butyl xanthate and oil No. 2, etc., has been conducted by using the cyanide process in the tungsten concentrator. The process has problems of high reagents consumption (25 tonne of cyanide dosage per year) and mineral processing cost (800~1000 RMB reagents cost per tonne of by-product concentrates), high mutual containing loss in the by-product concentrates and serious environmental pollution caused by lots of cyanide-containing wastewater. In order to solve this problem, a new cyanide-free separation technology is studied, which is used to process this sulphides bulk concentrate with 8.68% Cu, 8.98% Zn, 0.26% Mo, 1.58% Bi and 40.12% S. The results of the closed circuit test show that Cu, Zn, Mo and Bi can effectively be separated from this sulphide minerals concentrate by using the reasonable flotation-gravity flowsheet, high-efficiency collectors and regulators simultaneously. The metallurgical recovery and concentrate grade are as follows: molybdenum recovery is 94.63% with 50.62% Mo content; copper recovery is 85.18% with 29.29% Cu content; zinc recovery is 75.92% with 46.49% Zn content; total Bi recovery is 65.08% with 16.86% Bi content. The new technology is an alternative to the cyanide process due to its low cost for reagents, satisfying separation results and economic profits, and solves the problem of environmental pollution caused by the use of large quantities of cyanide. Some important parameters in separating the Cu-Zn-Mo-Bi sulphides concentrate are also introduced in this paper. This study provides pretty good technical support for separating the polymetallic sulphide ores containing Cu, Zn, Mo and Bi by cyanide-free technique."

Jan 1, 2014

Study on Separation Technology for Copper-Molybdenum Collective Concentrate

Sep 13, 2010

By Jing Chai

The Cenozoic unconsolidated strata with the thickness of 100 to 240m in the east area of China are composed of clay, sandy clay and hardpan, etc. Numerous shafts of the coal mines in these areas have been damaged to various degrees since 1987, with the main reason for this being the subsidence of the super-thick unconsolidated strata. To prevent the continuing settlement deformation of unconsolidated strata caused by groundwater removal, long-term water injection through multiple boreholes controlled the settlement deformation of unconsolidated strata. A new type of fiber Bragg grating (FBG) sensing system was successfully used for real-time strain monitoring of the unconsolidated strata during water injection at a coal mine in China. A mathematical model for the compression settlement induced strain calculation is proposed which can assist understanding of the effect of water injection on the ground. With the increase in water injection, the unconsolidated strata compressed state was improved by the transition of the stress state from compressive to tensile stress. The wavelength change of fiber Bragg grating sensors corresponded with the trend of the water level in the same strata. Engineering practice indicates that these sensors can normally, safely and reliably survive conditions associated with hydrous unconsolidated strata. The FBG sensing can be used for continuous lifetime monitoring of the system, starting with real-time monitoring during low-pressure water injection process of multi-borehole. The results will give important guidance for water injection and mastering stratum subsidence.

Aug 1, 2013

By Wenshan Zhang

Three important methods of removing Fe in hydrometallurgy of zinc, manganese, copper, nickel, cobalt and etc are described, including neutralized hydrolysis method, jarosite method and goethite method. The reactions, technical requirements and thermodynamic analysis during Fe removal process are also discussed in this paper.

Jan 1, 2006

By Huimin Lu, Qiang Li, Jingbo Xu

"The smelting reduction of V-Ti bearing beach placer by combined rotary hearth furnace and direct current arc furnace was studied in laboratory. It takes the aid of back propagation (BP) neural network theory to build the nonlinear mapping relations between the crucial process variables such as content of carbon, temperature and time and the degree of reduction. Then by the integrating BP neural network and genetic algorithm (GA), the optimized process parameters for the high degree of reduction were searched. The comparisons between experiment results and neural network simulation results show that GA-based on BP method can predict the degree of reduction with higher prediction accuracy. Calculations show that the integrated energy consumption of new technology is 580kgce/tHM, less than the current existing blast furnace.IntroductionThese V-Ti bearing beach placers (VTBBP) are secondary Fe-rich minerals formed by rivers, ocean waves, ocean tides and ocean currents on beach zones, their useful minerals are V-Ti magnetite ores. On Asia Pacific zone, such as Japan, China, Philippines, Indonesia, Australia and New Zealand, the VTBBP have large reserves and wide distribution. But so far, the VTBBP are not still comprehensively utilized. Therefore, in this paper, a combined rotary hearth furnace technology and arc furnace smelting method is studied for comprehensive utilization of the VTBBP. The main objective of this paper is to find optimum operation conditions for the production ofV-bearing iron and titania-rich slag from the VTBBP by means of the laboratory testing.Recently, neural network (NN) expected to be able to provide an effective tool because of its advantages, which describe nonlinear mapping relations. With the characteristics of strong selflearning, self-organization, robust error toleration and accurate nonlinear relation approximation, artificial neural network can be applied to nonlinear process modeling based on sufficient training. Back-propagation (BP) training algorithm is probably the frequently used one in practical application. Genetic algorithm has parallel search strategy and global optimization characteristics, which makes the trained neural network being higher classification accuracy and faster convergence speed. So it is necessary to combine neural network and genetic algorithm. The nonlinear relationship between input and output presented by NN and the global optimal function of GA are abroad applied in the engineering and scientific research [1, 2]. So these methods supply an efficient path to solve the above problems. At present, it is common to study the optimization of process parameters by orthogonal experimental design, the method combining neural network and genetic algorithm is a novel and better method than orthogonal experimental design. Tills study organized the above advantages to optimize the process parameters for comprehensive utilization of the VTBBP."

Jan 1, 2012

By Wang Jia, Chai Li-yuan, Zhang Jin-Long, Peng Bing, Zhang Qiang

"Electrolytic manganese dioxide (EMD) residue was mixed with shale and fly ash as the main materials to make solidification/sintering brick for the utilization of the residue from EMD production. The effects of sintering temperature, sintering time, solid waste content and cooling process on its mechanical properties and toxic elements solidification were investigated according to compressive strength and leaching toxicity. The results showed that the calcined residue had capability of solidifying toxic metals and exhibited perfect strength after treated in the optimal parameters of EMD residue below 50%, temperature at 1000-1100°C, time3-5h, and semi-quenched at 600°C1 InstructionSolid clay-brick holds the leading position among building materials for a very long time in China. The traditional technique of making clay-brick has the drawbacks of backward process, simple facilities and single product. Since Chinese Reform and Opening-up, urban-rural construction and real estate have been booming with the rapidly development of national economy and science technology. The problems of ruining fertile land, environment contamination and high energy consumption in the traditional technique of clay-brick making have not been solved yet. On the other hand, more than 7 billion tons of industrial wastes are accumulated over years which occupies over 6.7 million hectares filed and causes serious environmental problems[1-31. Strategy present in ""The Chinese Agenda of the 21st Century"" required the production of wall materials less energy conservation, land saving and waste recycling.Coal gangue[4-9l, fly ash[I0- 13l, sludge from waste water treatment and tailings of gypsum, pyrite, copper mine, high silicon containing iron, asbestos and ects [l4-lSJ are the solid wastes used for brick making around the world. There are two kinds of process for brick making, high temperature sintering and low temperature steam curing[19•201. Although the technology of two brick making made great progress and got widely application in construction field, no precedent for preparing sintering-bricks with EMD residue as materials occurred in China because of its complicated processing technics and lack of sufficient practical experience to guarantee the bricks' quality.In this study, EMD residue was mixed with shale and fly ash as the main materials to make solidification/sintering brick. The effects of sintering temperature, sintering time, solid waste content and cooling process on its mechanical properties and toxic elements solidification were investigated according to compressive strength and leaching toxicity."

Jan 1, 2011

By Jiawang Hao, Qinglong Zhang, Liang Han, Chuhan Wang, Shenfang Chen, Lan Qiao

The surface collapse and surrounding rock failure caused by goaf instability are the mining disasters that cannot be ignored. It is of great value to evaluate the stability of goaf accurately and treat it economically for the mine safety and the maintenance of ecological environment. However, in previous studies based on numerical simulation methods, the spatial complexity and the irregularity of actual goaf were not considered. Therefore, based on the internal space data of goaf obtained by high-precision laser detector, the goaf stability was comprehensively analyzed through Plaxis software and two-stage fuzzy judgment theory in this study. To effectively improve the goaf stability, the optimal backfill parameters for the goaf treatment were obtained by a series of mechanical tests. The research results provide some good references for the stability evaluation and the treatment of underground goaf.

Sep 26, 2023

In order to ensure safe mining and reduce surface damage in shallow multiple-seam mining, the failure characteristics of interburden strata with different coal pillar offset distances between pillars in the upper and lower seams, the distribution characteristics of stress concentration in coal pillars, and the development characteristics of stratum cracks and subsidence were physically investigated and also using UDEC2D software. Meanwhile, the effect of different coal pillar offset distances on the stress concentration of coal pillars and development of stratum cracks were studied. Based on those results, a formula for safe mining and reducing surface damage was established, which provided a theoretical basis for safe and environmentally friendly mining in shallow multi-seams. According to the results of the study, the optimal coal pillar offset distance (the side-to-side horizontal distance of the upper and lower coal pillars) between the upper and lower coal seams was developed to reduce the stress concentration of coal pillars and surface damage. The results of this study have been applied in Ningtiaota coal mine and have achieved good results in safe and environmentally friendly mining.

Jul 28, 2020

By Linghu Changjin

Based on the characteristics of typical marine sedimentary phosphate rock in Guizhou, Southwest China, together with the research findings made on the surface electric properties of pure collophanites taken from different areas in pure water and under the action of collectors, a pure minerals flotation test of collophanite was conducted in this research. The differences of collophanite flotation behavior and the effects of the different pH values, varieties, and dosage of collector on flotation separation of collophanite were studied. It is suggested that that in pure water, collophanite had a negative charge within a wide pH range. The electro negativity values of collophanite increased with the addition of collectors GJBW and WF-01. When GJBW and WF-01 were used as collectors, the collophanite was depressed in acid medium, but had a good flotability in basic medium.

Sep 1, 2012

By Zhucheng Huang, Zhikai Liang, Lingyun Yi, Tao Jiang

"In this study, reduction of iron ore pellets was carried out at 800-950°C by simulating the atmosphere of typical coal gasification gas. The effects of temperature, gas composition and reduction degree on swelling were investigated respectively. Reduction degree was obtained according to the weight loss records. And volume changes of pellets during reduction were evaluated by infrared photography. Results showed that the pellet swelling increased with temperature and decreased slightly with hydrogen content in the reducing gas. The swelling peaked when reduction degree reached about 40% and then decreased to be stable finally. The microstructures of pellets during reduction were examined by reflected light microscope and relatively rational explanations were proposed for their swelling behaviors.PrefaceDirect reduction iron is an important and indispensable raw material for high-purified and high-quality steel in the electric furnace smelting. Gas-based shaft furnace direct reduction process has very strong competitative ability; however, this technique requires natural gas as reducing agent, so its development has been restricted by gas source and area. Compared with gas-based reduction method, coal based reduction method has the disadvantages of higher production cost and lower productivity. In China, coal resources are abundant and coal gasification technology is mature, and the development of coal gasification shaft furnace direct reduction process is promising. [1] The gasification methods of fixed bed method (Lurgi method), fluidized bed method (Undok method), airflow bed method (Texaco coal water slurry method and Shell dry powder coal method) have been put into use successfully. These syngas generated by different methods can meet the actual production requirement of shaft furnace. However, the compositions of the effective reduction gas in the syngas are quite different. The ratios of hydrogen and carbon monoxide (H2/CO) of Undok or Shell coal gas, Texaco coal gas and Lurgi coal gas are 0.4, 0.6~ 1.0 and 1.6~2.3, respectively. [2] In the coal gas direct reduction process, the swelling behavior of iron ore pellets is various due to the differences of the gas composition, reduction temperature and reduction degree, and it seriously affects the normal operation ofDRI production. [3-9] Therefore, the research on the swelling behavior and its mechanism of iron ore pellets in direct reduction were carried out in this paper."

Jan 1, 2013

By F. Z. Dong

The paper is mainly about a study on the techniques of separating iron from pyrite cinder of a certain sulfuric acid plant in Shandong province. The main components of the cinder are Fe2O3 and SiO2, and the degree of liberation of iron mineral and gangue is very high. So the iron concentrate with higher degree of iron and lower grade of silicon and sulfur can be achieved by reverse flotation. The iron grade of the concentrate reaches 63% and the recovery of iron is no less than 63%. And the most important influencing factor of the flotation is the temperature of the pulp. A better guideline can be achieved by magnetic separation. The cinder is magnetizing roasted for 15 minutes with temperature of 800?, and the concentrate with the iron grade 64%, sulfur grade 0.2% and iron recovery 85% can be obtained by two stage magnetic separation. A rotary kiln has been built to deal with the pyrite cinder, and the result of the industrial magnetizing experiment and magnetic separation is satisfying.

Jan 1, 2014

By S. J. Lui

Sodium oleate was an effective diaspore collector, whereas chelate collector OL2 showed certain collecting power over diaspore and nonionic surfactant OL3 showed little collecting ability. Then experiments were carried out using sodium oleate as the main collector with the addition of OL2,OL3 to study the influences on diaspore flotation, it could be seen from the experiments that accelerants had a marked influence on the recovery of diaspore, which could be raised by 10%, and the addition sequence also affected the flotation behavior: the best results could be gained when the accelerants were mixed thoroughly before adding and the best ratio of collector OL1 and accelerant OL2, OL3 stood at 30:2:1. Based on the calculation of the ingredients in the sodium oleate solution, sodium oleate reacted with surface of the mineral and formed the acid-soap polymer [HOl?Ol-] when pH was about 9. Zeta potential test showed the accelerant promoted the absorption of collector on the mineral surface, which lowered zeta potential. As could be seen from surface tension experi-ments, the addition of accelerant OL3 lowered the CMC value of OL1 solution, which was equiva-lent to raise the power of the agents. Further Infrared Ray experiments showed the co-absorption of OL1 and OL2 make aluminum oleate on the mineral surface more stable. Up till now, the mixed reagents with sodium oleate as the main collector, combined with other two accelerants had been used in the Zhongzhou concentration plant, which is the first diaspore flotation plant in China.

Jan 1, 2014

By X. H. Li, Q. Zhang, X. Fei

Bauxite residue known as red mud (RM) is a by-product produced in massive quantities during alumina production by the Bayer process with a utilisation rate of less than 5%. A large amount of RM accumulated and produced continuously has had a seriously adverse impact on the surrounding ecological environment. The application of RM in building materials is considered to be the most effective and thorough way to make RM harmless and recycle resources for the reason that adding RM to concrete as a mineral admixture could not only consume a lot of RM, but also save cement and other energy-consuming industrial products. In this paper, the adaptability to cement and aggregate of RM was studied. The results showed that the compressive strength and flexural strength of concrete using ordinary Portland cement, slag Portland cement or fly ash Portland cement as cementing material showed different trends with the increase of the amount of RM. The influence rules of RM on the compressive strength of Portland cement, slag Portland cement and fly ash Portland cement concrete were similar, whether for silicate aggregate or carbonate aggregate. RM has a negative correlation to the flexural strength of silicate aggregate-ordinary Portland cement concrete, but a positive correlation to silicate aggregate-slag Portland cement, silicate aggregate-fly ash Portland Cement. RM promoted the formation of calcium carbonate crystals and inhibited the formation of ettringite and calcium hydroxide crystals in the matrix while ordinary Portland cement, Portland cement and fly ash Portland cement were used as cementing materials. This study provided support for the use of RM in concrete, the reduction of solid waste storage, and the saving of high energy consumption cement as well. Keywords: Red mud, cement, aggregate, adaptability, mechanical properties, mineral composition

Jan 1, 2020