25 August 2025, Volume 45 Issue 4
    

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    MINING
  • Energy Characteristics of Progressive Damage in Dolomite Under Dry-Wet Cycle and Cyclic Loading and Unloading Conditions
    ZHANG Feng, WANG Yunmin, LI Xiaoshuang, LU Jun, HOU Guoqing
    Mining and Metallurgical Engineering. 2025, 45(4): 1-7. https://doi.org/10.3969/j.issn.0253-6099.2025.04.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The mechanical properties and energy evolution law of dolomite under a combined action of dry-wet cycle and cyclic loading and unloading were explored. The results show that the structural damage caused by dry-wet cycles leads to the transformation of dolomite from brittle fracture to ductile fracture, which is manifested by an increase in the area of hysteresis loops and a decrease in peak strength. At the early stage of cyclic loading and unloading, a strengthening effect is observed, and then the dolomite develops into the strain-softening and damage stages. An energy analysis indicates that the total input energy is mainly stored in the form of elastic strain energy, and the proportion of dissipated energy increases slowly with the accumulation of damage. Additionally, based on the variation of the damage variable defined by dissipated energy, the damage evolution tends to be stable after a progressive and accelerated process.
  • Competitive Landscape and Coping Strategies for International Seabed Exploration Areas
    LIU Chengjun, LI Manhong, ZHENG Hao, SHUANG Zhi
    Mining and Metallurgical Engineering. 2025, 45(4): 8-13. https://doi.org/10.3969/j.issn.0253-6099.2025.04.002
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the characteristics of the exploration contracts approved by the International Seabed Authority (ISA), the global competition status and variation trend of the exploration contract areas are analyzed in terms of temporal changes, spatial distribution and mineral types. Based on the analysis results, strategies to cope with the variation in the situation of ISA exploration contract areas are proposed, including commercial companies acting as the main players, strengthening international cooperation with African countries and the Enterprise of ISA, giving priority to exploration of polymetallic nodules, cultivating advantageous contractors and safeguarding the rights and interests of contractors.
  • Analysis of In-Situ Leaching Characteristics and Scheme Optimization Based on 3D Heterogeneous Model
    LUO Guijun, JIA Mingtao, ZHANG Chuanfei, YANG Yihan, CHENG Meifang
    Mining and Metallurgical Engineering. 2025, 45(4): 14-21. https://doi.org/10.3969/j.issn.0253-6099.2025.04.003
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    A 3D heterogeneous numerical model was established based on the C6# mining area of the Bayan-Uul uranium deposit to analyze the effects of different horizontal permeability in the filter section on solute transport, pH value and uranium mineral leaching performance. The simulation results show that after 450 days, the uranium leaching rate is 13.56% at the vertical depth of 30 m in the filter section, presenting 22.71% higher compared to the leaching rate of 11.05% at the depth of 35 m. According to the sandstone permeability, grade of uranium in the stratum and heterogeneity, the vertical arrangement position and length of filter section can be optimized, so as to effectively improve the economically recoverable metal quantity.
  • Experimental Study on Fracture Characteristics of Rocks with Bent Cracks Under Saturated Conditions
    MA Yan, LIU Zelin, WANG Ze
    Mining and Metallurgical Engineering. 2025, 45(4): 22-27. https://doi.org/10.3969/j.issn.0253-6099.2025.04.004
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To investigate the fracture characteristics of rocks with bent cracks under saturated condition, uniaxial compression tests were conducted for rock specimen with different inclination degrees and numbers of crack bends under saturated conditions to study load-displacement curves, peak strength, acoustic emission characteristics, crack initiation modes, and penetration modes of the rock specimen. The results show that the load-displacement curve of saturated rock specimen with bent cracks presents one-peak or double-peak shape, with peak strength increasing after an initial decreasing as the crack inclination angle becomes larger. The acoustic emission signals become stronger as the crack inclination angle becomes larger and the number of crack bends increases. Cracks mainly initiate at the tip and bends, and mainly penetrate directly or run without penetration.
  • Impact of Near-Surface Ore Body Mining on Stability of Overburden and Dangerous Rock Masses on Slopes
    JIA Liang, JIANG Anmin, WANG Feifei, ZHENG Changhui, WU Kuan, REN Qingyang
    Mining and Metallurgical Engineering. 2025, 45(4): 28-32. https://doi.org/10.3969/j.issn.0253-6099.2025.04.005
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To explore the impact of near-surface ore body mining on the stability of overburden and dangerous rock masses of slopes, a phosphate mine was taken as an engineering project in the study. The stability of the dangerous rock mass of the slopes was determined by on-site investigation, and the evolution of deformation, stress and plastic zone of overburden under different mining schemes were simulated with FLAC3D software. The research results indicate that structural planes between layers of surrounding rock on the roof of stope are well-developed, probably causing falling debris in blocks or flakes. The strata are hard and brittle in lithology and have developed rock fractures. Under unloading effect of high and steep slopes, dangerous rocks are prone to be separated along the combination of fractures and strata plane, forming dangerous rock masses. The response law of the maximum stress in the overburden is similar to the law of the unbalanced force in numerical calculation. There is relatively small disturbance generated during mining process, which brings a little impact to the stability of adjacent stopes and surface. It is found that the ground surface is less affected by underground mining, with the deformation within the maximum limit value specified in the standard. If Ph2# ore body is mined after Ph1# ore body, the overburden can have relatively small displacement, and no connectivity in the plastic zones is occurred in the mining pillars, stopes and overlying strata.
  • Reasonable Drift Spacing for Eastern Stopes of Jinshandian Iron Mine Considering Influence of Moisture Content on Drawn Ore Blocks
    WU Zhongying, MEI Linfang, ZENG Yunchuan, WANG Wenjie
    Mining and Metallurgical Engineering. 2025, 45(4): 33-40. https://doi.org/10.3969/j.issn.0253-6099.2025.04.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To address the problems of poor fluidity and high viscosiy, ore rocks and higher ore losses and dilution due to the influence of moisture content on eastern stopes of Jinshandian Iron Mine, the variation laws of fluidity of ore blocks, shape characteristics of drawn ore blocks, as well as loss and dilution indices of two types of ore bodies in the eastern stopes under influence of different moisture content were analyzed by preforming physical tests and numerical simulation. A reasonable range of drift spacing for the eastern stopes was determined, which was then optimized from the perspectives of safety, technology and economy, based on the improved CRITIC-TOPSIS evaluation method. The results show that with the moisture content in a range of 0-8%, the drawn ore blocks in the eastern stopes are in a shape of an “inverted water drop”, and become shallow as the moisture content increases; with the moisture content in a range of 4%-8%, the natural angle of repose of ore rocks increases with the increase of moisture content, the recovery rates of those two ore bodies are negatively correlated with moisture content, and present an upward trend followed by a decline as the drift spacing becomes wider, while the dilution rate follows the opposite trend. With the moisture content at 6% on average, the optimal drift spacing in the eastern stopes of Jinshandian Iron Mine should be set at 15 m.
  • Stability Analysis of Concave Open-Pit Slope Based on FMM-SVR Model
    ZHOU Qingqing, MU Lin, WANG Lei
    Mining and Metallurgical Engineering. 2025, 45(4): 41-46. https://doi.org/10.3969/j.issn.0253-6099.2025.04.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The parameters of the Fuzzy Measure Method (FMM) in slope stability analysis are difficult to determine, thus a support vector regression (SVR) model was established and used to accurately predict parameters of the FMM, and a slope stability prediction model, FMM-SVR, was established, which was then used to predict the instability probability of the slope during the second-phase open-pit mining in Gaocun Iron Mine of Masteel Mining Resources Corporation. The results show that the maximum slope instability probability is 0.1208 as mining operation approaches the toe of slope in an open pit, indicating that the slope remains overall stable with a risk of partially instability. This conclusion is also consistent with the on-site measured results. The location of the most critical sliding surface of the slope was determined by the finite element strength reduction method, and the factor of safety is calculated to be 1.5, which further verifies the effectiveness of the FMM-SVR model.
  • Recognition of Rock Fracture in Open-Pit Mines by Borehole Imaging Based on Improved U-Net Model
    SONG Wenyao, ZHANG Mei, GUO Lianjun, DENG Ding, GAO Chong, ZHAO Xin
    Mining and Metallurgical Engineering. 2025, 45(4): 47-51. https://doi.org/10.3969/j.issn.0253-6099.2025.04.008
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the accuracy of fracture recognition in borehole images, a borehole fracture recognition approach for open-pit mine was proposed. First, borehole images of an open-pit mine is obtained with an intelligent borehole inspection camera, and then data augmentation is performed by using random cropping and image flipping, while median filtering is used for noise reduction and images are converted to grayscalere, so as to eliminate noise and reduce computational complexity. Next, spatial attention and channel attention mechanisms are integrated into the U-Net model to improve the semantic segmentation model for fractures, forming an AU-Net model, which can enhance the model′s ability to extract features from both overall and local image information. Experimental results show that compared to the original U-Net model, the AU-Net model can achieve lower loss and higher accuracy in the fracture recognition dataset by borehole imaging. Specifically, the mean intersection over union is improved by 4.38 percentage points, up to 82.34%, bringing better image segmentation effect.
  • Optimization of Mining Methods for Gently Inclined Phosphate Ore Body Based on Improved AHP-TOPSIS Model
    WU Shangrong, CHEN Banghong, FEI Zhiwen
    Mining and Metallurgical Engineering. 2025, 45(4): 52-57. https://doi.org/10.3969/j.issn.0253-6099.2025.04.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to solve the problems of fuzziness, randomness and uncertainty in optimization of mining method by traditional analytic hierarchy process (AHP), some measures, including introducing fuzzy theory, optimizing judgment scale and constructing optimal transfer matrix, were introduced to reduce subjective deviation and enhance the processing ability of uncertain information. Then, based on the combination of improved analytic hierarchy process (AHP) with the technique for order preference by similarity to ideal solution (TOPSIS), a comprehensive evaluation system with multi-level, multi-factor, multi-objective and multi-index characteristics was constructed and applied to the optimization of mining methods for a gently-inclined medium-thick phosphate ore body. The analysis shows that the relative closeness coefficients of those three mining schemes are 0.177 9, 0.822 5 and 0.648 3, respectively. Scheme 2, namely sublevel open stoping with subsequent backfill, is primarily determined as the suitable mining method for the mine. The numerical simulation of Scheme 2 also shows that the maximum surface subsidence in this scheme can be controlled within 72.94 mm, indicating that the mining operation at this stage brings little impact to the surface industrial zone on the mining site.
    • MINERAL PROCESSING
  • Experimental Study on Stepwise Flotation Recovery of Copper-Gold ore from Xizang
    JIANG Feng, WANG Pengyuan, WEN Zhisen, LIU Chunlong, HE Xiaomin, LIAO Jinling, SUN Wei
    Mining and Metallurgical Engineering. 2025, 45(4): 58-62. https://doi.org/10.3969/j.issn.0253-6099.2025.04.010
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A copper-gold ore from Xizang grades 0.50% Cu and 0.24 g/t Au, in which chalcopyrite as the dominant copper mineral is finely disseminated. It was proposed that a stepwise flotation process be employed to process this ore. At the first-stage roughing, a non-polar collector CM-2 was adopted under low-alkaline conditions to recover those easily floatable copper and gold minerals, and at the second-stage roughing, Z-200 was adopted to enhance copper flotation effect, so as to improve the recovery rates of copper and gold. A closed-circuit experiment yielded a copper-gold concentrate grading 22.33% Cu and 9.96 g/t Au at the corresponding recoveries of 90.57% and 79.83%, respectively. Compared to high-alkaline flotation processes with ethyl xanthate or Z-200 as collectors, this stepwise flotation process can increase gold recovery by more than 10 percentage points. This technical process can not only avoid depression effect of lime on gold minerals, but also strengthen the collecting effect of copper and gold minerals, thus achieving efficient resource recovery. This study can provide a reference for exploitation and utilization of similar ores.
  • Beneficiation Experiment of Low Grade Niobium Ore for Super Enrichment
    ZHOU Yulin
    Mining and Metallurgical Engineering. 2025, 45(4): 63-67. https://doi.org/10.3969/j.issn.0253-6099.2025.04.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A beneficiation experiment for super enrichment was carried out with the low-grade niobium ore from western zone of Bayan Obo mine. In the experiment, a process of magnetic separation followed by gravity concentration for tailings discarding was firstly adopted for pre-concentration, and the obtained rougher concentrate grading 2.61% Nb2O5 was subjected to a reverse flotation for desulfuration, followed by a direct flotation with CYN-7 as a collector and CYD-2 as a depressant  for recovering Nb minerals, resulting in efficient separation between Nb and other gangue minerals. It is found that the raw ore grading 0.06% Nb2O5, with a grinding fineness of -0.074 mm 85% is treated by magnetic separation and gravity concentration for tailings discarding, followed by a reverse flotation for desulfuration, and a direct flotation consisting of one stage of roughing and three stage of cleaning. As a result, a Nb concentrate grading 22.37% Nb2O5 at 33.64% recovery can be finally obtained.
  • Experimental Study on Combined Process of Magnetic Separation and Gravity Separation for an Ilmenite Ore
    SHI Yunpeng, LIANG Bin, LI Shiwei, LU Manman, ZHANG Hanquan
    Mining and Metallurgical Engineering. 2025, 45(4): 68-72. https://doi.org/10.3969/j.issn.0253-6099.2025.04.012
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to comprehensively recover titanium resources and iron resources from a low-grade ilmenite ore, an experimental study was performed for the ore by a process of low intensity magnetic separation (LIMS) followed by regrinding and re-concentration to recover Ti and Fe therein. The results show that LIMS with ore at a grinding fineness of -0.074 mm 84.78% can yield an iron concentrate grading 62.82% TFe and 3.62%TiO2 with iron recovery of 51.32%, presenting a good recovery of magnetic iron; the obtained LIMS concentrate is subjected to high-intensity magnetic separation (HIMS) consisting of one roughing and one cleaning, followed by gravity separation with a shaking table, resulting in the obtained Ti concentrate grading 40.81% TiO2 at 18.47% recovery. It is shown that both Fe and Ti therein can be comprehensively recovered.
  • Effect and Mechanism of Oxidation for Floatability of Chalcopyrite
    DONG Lixin, DAI Shujuan, LI Pengcheng, LIU Ziyuan, YANG Fangyuan, LUAN Jingchun
    Mining and Metallurgical Engineering. 2025, 45(4): 73-78. https://doi.org/10.3969/j.issn.0253-6099.2025.04.013
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    Single mineral flotation tests of chalcopyrite oxidized respectively in air and water were carried out under optimized conditions such as pulp pH and collector dosage. The mechanism for oxidation bringing effect to  the floatability of chalcopyrite was studied by measuring contact angle and Zeta potential, and using infrared spectroscopy. The results show that the recovery of oxidized chalcopyrite with collector JXZZ  is higher than those using DJHY and BXZX; the surface hydrophobicity of chalcopyrite oxidized in air and water can be improved; the area of CO2 absorption peak increases with the increase of air oxidation time, air oxidation temperature and water oxidation time, and all the three collectors can be chemisorbed on chalcopyrite. After oxidation, point of zero charge of oxidized chalcopyrite shifts positively, while the oxidization state of chalcopyrite in water is comparatively stable. It can be concluded that the floatability of chalcopyrite can be regulated by surface oxidation of this ore.
  • Influence of Pre-desliming on Flotation Performance ofCopper-Bearing Magnetite from Anhui Province
    LAI Fulai, SHEN Chong, ZHANG Chuan, REN Haibo, HU Yang
    Mining and Metallurgical Engineering. 2025, 45(4): 79-83. https://doi.org/10.3969/j.issn.0253-6099.2025.04.014
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    The ore in the concentrator of Anhui Taiping Mining Company cannot reach the expected flotation effect. In order to address the problem, the properties and particle size composition of raw ore were analyzed, and condition tests were conducted to rule out the influence of reagent system and flotation conditions on the flotation performance. Based on a test on pre-desliming  of the raw ore sample before grinding and the concentrate from pretreatment, it is found that the secondary slime has a significantly superior floatability than the primary slime, and too much primary slime is a contributing factor in the finally poor flotation performance. And based on a test on comparison of desliming, it is found that after pre-desliming process, the flotation effect of ore can be obviously improved, and the concentrate can have its final recovery improved by around 10 percentage points compared to that without pre-desliming process, due to significantly decreased slime content in concentrate and middlings. It is concluded that pre-desliming process is an effective approach for improving flotation performance of such kind of copper-bearing ore with serious sliming.
  • Experimental Research on Beneficiation of Complex Low-Grade Associated Fluorite Ore in Hunan Province
    YI Luan, LIU Ming, YANG Hualing, WANG Changfu, DOU Zeping
    Mining and Metallurgical Engineering. 2025, 45(4): 84-89. https://doi.org/10.3969/j.issn.0253-6099.2025.04.015
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    Under the current production conditions, the fluorite concentrate obtained from the associated fluorite resources in a mine of Hunan Province has its processing indicators undesirable and fluctuating widely. In view of this technical bottleneck, a new processing technique was developed to recover such kind of fluorite ore for improving the quality of resources. In this technique, a principle of alkaline environment followed by acidic environment was adopted in the cleaning stage, and also the middlings obtained from the cleaning stage are returned to be processed again. As a result, a full-process closed-circuit test yielded 13.67% high-grade fluorite concentrate grading 96.11% CaF2 at 60.13% recovery, and 3.93% low-grade fluorite concentrate grading 85.08% CaF2 at 15.34% recovery. The comprehensive concentrate has a CaF2 grade up to 93.65%, with total recovery of 75.47%. It is concluded that this low-grade associated fluorite ore can be efficiently and comprehensively recovered using this technique.
  • Experimental Study on Mineral Processing ofa High-Magnesium Copper-Sulfur Ore
    TANG Xin, JIAN Sheng, ZHANG Jing, ZHANG Shuguang, LYU XiangWen, LIU Meihua
    Mining and Metallurgical Engineering. 2025, 45(4): 90-94. https://doi.org/10.3969/j.issn.0253-6099.2025.04.016
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An experimental study was carried out for mineral processing of a Cu-S ore with grade of MgO at 11.86%, grade of S at 6.81%. In the experiment, a flotation process, consisting of preferential flotation of copper, Cu-S separation and reverse flotation of copper concentrate for removal of magnesium, was adopted, with SG-2 as a copper collector in combination with HD as a depressant for magnesium-containing gangue, producing a standard copper concentrate grading 23.47% Cu and 2.99% MgO, with copper recovery at 81.10%.
  • Process Mineralogy and Flotation Test of Niobium-Bearing Ore from Africa#br#
    LIU Chao, HU Hongxi, ZHANG Zhonghan, HUANG Wei, YANG Jiping, CHEN Zhiqiang
    Mining and Metallurgical Engineering. 2025, 45(4): 95-99. https://doi.org/10.3969/j.issn.0253-6099.2025.04.017
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A process mineralogy study was conducted for a niobium-bearing ore in eastern Africa. Based on the study results, the raw ore was ground to -0.10 mm (100% passing size), and then pretreated with a process consisting of desliming, iron removal and zircon flotation for reducing the influence of slime, magnetite, and zircon on flotation performance. Under weakly acidic conditions, a closed-circuit niobium flotation test was carried out, with water glass and aluminum sulfate as a combined depressant, lead nitrate as an activator, and a self-developed chelating collector GYX2, producing a niobium concentrate grading 26.87% Nb2O5 at 88.31% recovery, with a corresponding recovery of 80.86% from the raw ore. It is concluded that the niobium minerals in the ore can be effectively recovered.
  • Experimental Study on Beneficiation of Fine-Grained Refractory Fluorite Ore in Hunan
    CHEN Xianggen, LIU Xin
    Mining and Metallurgical Engineering. 2025, 45(4): 100-104. https://doi.org/10.3969/j.issn.0253-6099.2025.04.018
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    A beneficiation test was performed with a kind of fine-grained refractory fluorite ore in Hunan Province for rational development and utilization. In the test, a  process consisting of coarse grinding, pre-concentration, regrinding and re-concentration of rough concentrate was adopted, with CYP-01 as a collector, sodium carbonate as a modifier, and water glass as a depressant. Depression in steps was performed in the cleaning stage. With the coarse grinding fineness of -0.045 mm 50%, regrinding fineness of -0.045 mm 85%, a kind of chemical-grade fluorite product with CaF2 grade of 93.04% was obtained at 64.24% recovery after one stage of roughing and eight stages of cleaning. It is shown that such kind of fine-grained refractory fluorite ore can be effectively recovered and utilized.
  • Application of Heavy-Duty and Efficient Thickener with Large Processing Capacity
    ZENG Jianhong
    Mining and Metallurgical Engineering. 2025, 45(4): 105-108. https://doi.org/10.3969/j.issn.0253-6099.2025.04.019
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An intermittent sedimentation test was performed for vanadium-titanium magnetite tailings to obtain settling curves of flocculated tailings, and then the solid flux in sedimentation by flocculation was calculated by Coe-Clevenger equation and material balance calculation. An innovative Φ38 m heavy-duty and efficient thickener is designed to have a unit area processing capacity of 1000 kg/(m2·h). The industrial application of this thickener in dewatering of vanadium-titanium magnetic tailings show that with dry ore processing capacity of 1100 t/h and the feed concentration of 20%－25%, its underflow has concentration of 45% and the overflow has solid content less than 200 mg/L. It is concluded that such thickener can solve the technical problems in the production faced by enterprises, and also bring enterprises enhanced economic and environmental benefits.
  • Optimization and Upgrading of Grinding and Classification Processin Luzhong Concentrator
    LI Xiaolong, LUO Junkai, WU Chengyou, WANG Xiang
    Mining and Metallurgical Engineering. 2025, 45(4): 109-114. https://doi.org/10.3969/j.issn.0253-6099.2025.04.020
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    To address the problem in the existing grinding and classification system in Luzhong concentrator, the 5# grinding and classification system in the concentrator was optimized and upgraded by the following measures, including optimizing the working conditions of the autogenous mill, adding pre-concentration process with magnetic pulley for the oversized material of the drum screen and wet pre-concentration process before the ball mill, replacing the spiral classifier with a hydrocyclone group. Those measures can not only increase the actual processing capacity of 5# system to 232 t/h from 186 t/h, but also discard waste ore grading 7.05%TFe with a yield of 5.40%, presenting an iron loss rate of 1.25%. Meanwhile, +0.5 mm coarse sand can be produced with a yield of 12.63% and an iron loss rate of 3.86%. It is shown that in the first-stage overflow of the hydrocyclone, 44.09% product grading 53.00% TFe is yielded, indicating a good effect by optimization and upgrading measures.
    • METALLURGY
  • Mechanism and Process Optimization of Removing Calcium and Silicon Impurities from Chlorinated Slag by NaOH
    ZHANG Yaqi, HE Yongdong, WANG Huanghe, LIANG Feilong
    Mining and Metallurgical Engineering. 2025, 45(4): 115-121. https://doi.org/10.3969/j.issn.0253-6099.2025.04.021
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    To explore the removal mechanism of silicon and calcium and optimize the process, simulated chlorinated slag composed of silicon dioxide, calcium chloride and sodium chloride, was used as raw material in an experiment, with sodium hydroxide as an additive. The calcium and silicon ions were converted into high-melting-point solid phases, which were separated from the sodium chloride salt solution by filtration, thereby realizing regeneration and comprehensive utilization of the sodium chloride salt solution. Based on thermodynamic analysis, kinetic analysis, TG-DSC, XRD, ICP, SEM-EDS among other analysis measures, the conversion at high temperatures and removal mechanisms for calcium and silicon impurities, as well as the separation process of NaCl were all systematically explored. Thermodynamic analysis shows that a conversion can proceed spontaneously at temperatures ranging from 973 K to 1473 K. Fitting with the Kissinger method shows that the activation energy of the conversion at high temperatures is 296.21 kJ/mol, and the pre-exponential factor is 8.46×1010 s-1. The experimental results indicate that with calcium-silicon impurities and sodium hydroxide in a mass ratio of 1∶0.6, separation by filtration at 1123 K can lead to the removal rates of calcium and silicon up to 86.66% and 99.60%, respectively.
  • Extraction and Separation of Indium and Iron from Sulfuric Acid Leaching Solution of Volatile Dust from Zinc Smelting Process
    ZHANG Xilong, SHEN Yujun, PENG Jun, XIONG Weijiang, ZHOU Zhenghua, DING Jinze, CAI Yunzhuo
    Mining and Metallurgical Engineering. 2025, 45(4): 122-125. https://doi.org/10.3969/j.issn.0253-6099.2025.04.022
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    The process of extraction and separation of indium and Fe(III) requires a step of reduction of trivalent iron in advance and also emulsification is prone to occur. In order to solve the problems, an experimental study was carried out with acid leaching solution of volatile dust from a domestic large-scale zinc smelting enterprise to explore the processing technique of direct extraction with a extractant system of DY23 (a combination of extractant A and co-extractant M) to recover indium without a step of reduction of Fe(III) in advance. Based on the experiment, effects of organic phase concentration, phase ratio in extraction, extraction time and temperature on the separation between indium and Fe(III) were investigated. It is found that with a combined extraction system, consisting of 30% extractant A, 10% co-extractant M and 60% sulfonated kerosene, O/A ratio of 1∶1, the leaching solution of volatile dust is subjected to a two-stage countercurrent extraction at room temperature for 1.5 min, leading to indium extraction rate exceeding 99% and extraction rate of Fe(III) at only around 10%, presenting a good separation effect. The loaded organic phase is then subjected to a stripping process with 4 mol/L hydrochloric acid after being washed with 200 g/L sulfuric acid, leading to the stripping rate of indium exceeding 95%. After stripping of indium, the organic phase is subjected to another stripping with 70 g/L oxalic acid to remove Fe(III), resulting in the stripping rate of Fe(III) up to 98%. It is concluded that indium and Fe(III) therein can be effectively separated.
  • Experimental Study on Recovery of Scandium from Red Mud in Guizhou
    HUANG Yuanling, DENG Qiang
    Mining and Metallurgical Engineering. 2025, 45(4): 126-129. https://doi.org/10.3969/j.issn.0253-6099.2025.04.023
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    With the red mud from Guizhou as raw material, an experiment was carried out by adopting a process of low-temperature acidification  roasting followed by water leaching to recover scandium, and effects of factors, including sulfuric acid dosage, temperature and time for roasting process, liquid-solid ratio of leaching solution, leaching temperature and time, on scandium leaching rate were investigated. It is shown that after 4 h-roasting at 200 ℃ with sulfuric acid and raw ore in a mass ratio of 1∶1, and then 4 h-leaching at 80 ℃ with leaching solution and solid in a mass ratio of 6∶1,  the leaching rate of scandium can be finally up to  89.10%.
  • Visual Recognition of Float Flowmeter Readings in Sintering Process of Lithium-Ion Battery Cathode Materials Based on YOLOFFM
    HUANG Yong, LIU Yang, XIA Xing, XIAO Shengwang, LI Ran
    Mining and Metallurgical Engineering. 2025, 45(4): 130-136. https://doi.org/10.3969/j.issn.0253-6099.2025.04.024
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    To address problems of accuracy and efficiency in automatically reading of float flowmeter at low flow rates under a complex environment in sintering kilns for new energy materials, an innovative YOLOFFM algorithm was proposed. The core improvements include reconstructing the backbone network, enhancing the neck structure, introducing an asymmetric compression decoupling head, and optimizing the loss function, which can significantly improve the efficiency and detection performance of the algorithm. The results show that this YOLOFFM algorithm has accuracy up to 99.15% and a recall rate of 98.69%, significantly reducing the number of model parameters and computational costs. Compared with various advanced algorithm models, YOLOFFM can improve accuracy while reducing the computational cost by more than 90%, fully demonstrating its high efficiency and reliability for new energy materials in a complex environment of sintering kilns.
  • Application of Oxidative Precipitation for Iron Removal in Refining Nickel Sulfate
    JIANG Xuexian, WANG Lusen, ZHU Wenyun, HE Guixiang, LI Zhonglin, LI Yuanping, HE Zongqing, HUANG Caihong, YANG Yongming, CHEN Xiaolan
    Mining and Metallurgical Engineering. 2025, 45(4): 137-140. https://doi.org/10.3969/j.issn.0253-6099.2025.04.025
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In an experiment, oxidative precipitation method was adopted to remove iron from crude nickel sulphate solution. With H2O2 or Cl2 as oxidant, Fe2+ in the solution was oxidized to Fe3+, and then Fe3+ was precipitated in the form of Fe (OH)3 and FeOOH by adjusting the pH of the solution. It is found that under the optimum conditions for iron removal with H2O2 as the oxidant, including H2O2 dosage of 3.84%, temperature of 75 ℃, pH of 4.5, dropping of H2O2 solution at a rate of 0.33 mL/min, and the aging time of 90 min, the removal rate of iron can reach 99.74%. Under the optimal conditions for iron precipitation with Cl2 as oxidant, including reaction temperature of 70 ℃, pH of 4.5, Cl2 injection time of 60 min and aging time of 90 min, the iron removal rate can reach 99.72%. It is shown that the solution after iron removal with H2O2 or Cl2 as an oxidant can have the iron content therein up to the class I standard (iron content no more than 0.0005%) in GB/T 26524—2023 Refined Nickel Sulfates.
  • Experimental Study on Alkali Removal and Titanium Extraction from Red Mud with Tartaric Acid by Bayer Process
    LIU Wenbao, DING Rui, LI Weichao, LIU Wengang, SHEN Yanbai, ZHANG Qin
    Mining and Metallurgical Engineering. 2025, 45(4): 141-146. https://doi.org/10.3969/j.issn.0253-6099.2025.04.026
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With tartaric acid as a leaching agent, an experiment was conducted to investigate the effects of different leaching conditions on the leaching rates of sodium and titanium from red mud. The process parameters were optimized by orthogonal experiments, and the leaching mechanism was then analyzed in combination with the study of leaching kinetics and the properties of leaching residues. It can be seen from the leaching test and orthogonal experiment that with tartaric acid at a concentration of 1.00 mol/L, leaching temperature of 90 ℃, liquid-solid ratio of 8 mL/g, and leaching time of 60 min, the leaching rates of sodium and titanium from red mud can reach  93.50% and 76.66%, respectively. XRD analysis of red mud before and after tartaric acid leaching shows that the sodium in the leaching solution mainly comes from cancrinite and sodium hydroxide in the Bayer process, while the titanium mainly comes from perovskite and secondary titanium that dissolves and re-precipitates on the surface of red mud during the Bayer process. The leaching kinetics analysis shows that both alkali removal and titanium leaching from red mud conform to an unreacted shrinking core model, and the processes of alkali removal and titanium leaching are mainly controlled by interfacial chemical reactions.
  • Short-Process and Clean Preparation Technique for Battery-Grade Iron Phosphate
    MEI Zhenyong, YANG Li, GUO Qiang, LI Yongli, CUI Weiyong
    Mining and Metallurgical Engineering. 2025, 45(4): 147-152. https://doi.org/10.3969/j.issn.0253-6099.2025.04.027
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A new short-process preparation technique for battery-grade iron phosphate was explored with iron powder and phosphoric acid as main raw materials. The effects of iron powder dissolution mechanism, iron phosphate reaction conditions, and mother liquor recycle on product indicators were investigated. The results show that the dissolution rate of iron powder can reach 97.92% at a temperature of 70 ℃, with phosphoric acid at a concentration of 20%, iron and phosphorus at a ratio of 1/3, and iron powder at a size of 150 μm; after 1 h  precipitation at 100 ℃, with an addition of hydrogen peroxide at 110% of the theoretical amount, an iron phosphate with D50 of 2 μm was prepared with the precipitation rate of 98.86%. The obtained iron phosphate has stable crystal form with uniform crystal grains, and the contents of elemental impurities are significantly lower than the requirements specified in the HG/T 4701—2021 standard. The precipitated mother liquor in the process can be recycled, leading to actualization of  low-carbon and green production.
  • Experimental Study and Application of Membrane Distillation Technology in Treating High-Salinity Wastewater
    CHEN Boming, SUN Wei
    Mining and Metallurgical Engineering. 2025, 45(4): 153-157. https://doi.org/10.3969/j.issn.0253-6099.2025.04.028
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An experiment was carried out on treating high-salinity wastewater by air gap membrane distillation (AGMD). Effects of different operating conditions on the performance of AGMD were investigated, and membrane fouling and its control measures were also analyzed. It is shown that the permeation flux increases with the increase of temperature and flow rate of feed, and decreases with the increase of cooling water temperature and salt concentration. The salt rejection rate can maintain above 99.8% with the salinity less than 60 g/L, and still exceed 90% with salinity within the range of 60-100 g/L. It is concluded that AGMD technology can be adopted to treat high salinity wastewater.
    • MATERIALS
  • Sodium Storage Performance of Bamboo-Derived Hard Carbon Materials Prepared by Different Impurity Removal Processes
    DU Haojie, ZHANG Lei, WANG Qinmeng, GUO Xueyi, TIAN Qinghua, TONG Hui, XUE Zhiqiang, LUO Yuecheng
    Mining and Metallurgical Engineering. 2025, 45(4): 158-163. https://doi.org/10.3969/j.issn.0253-6099.2025.04.029
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With bamboo as a raw material, different hard carbon materials were prepared by different impurity removal processes, and the effects of those processes on the impurity content, physical structure and sodium storage performance of hard carbon were explored. The results show that after impurity removal treatment, the bamboo-derived hard carbon has reduced impurity content and specific surface area, and increased interlayer spacing. With the preparation cost and the sodium storage performance of hard carbon comprehensively taken into consideration, acid leaching is chosen as the impurity removal process for hard carbon. It is shown that at a current density of 30 mA/g, the anode material with prepared hard carbon can have an initial Coulombic efficiency of 83.87% and a reversible specific capacity of 308.96 mAh/g; it demonstrates a capacity retention rate of 96.57% after 100 cycles at a current density of 300 mA/g, showing excellent sodium storage performance.
  • Effect of Heat Treatment on Microstructure and Hardnessof W6Mo5Cr4V2 Steel
    LIU Dong, TAO Jun, KUANG Yuan
    Mining and Metallurgical Engineering. 2025, 45(4): 164-167. https://doi.org/10.3969/j.issn.0253-6099.2025.04.030
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Effects of quenching and tempering at different temperatures on the microstructure and hardness of annealed W6Mo5Cr4V2 steel were studied by means of OM, SEM, XRD analysis and hardness test. The results show that the microstructure of quenched W6Mo5Cr4V2 steel is mainly composed of martensite, MC carbide rich in V, W and Mo, and M6C carbide rich in W and Mo, as well as residual austenite. As tempering temperature rises, the carbide in the microstructure of W6Mo5Cr4V2 steel grows in size, and the hardness decreases after an initial increase. After quenching at 1160 ℃plus three times of tempering at 540 ℃, W6Mo5Cr4V2 steel has its carbide become smaller and evenly distributed, and its residual austenite almost eliminated, showing the hardness up to 64.2HRC.
  • Additive Manufacturing of Complex Shaped SiCp/AlComposite by Photocuring Process
    QIAO Congzhuo, LIU Zirui, XU Qikai, WANG Richu, PENG Chaoqun, WANG Xiaofeng
    Mining and Metallurgical Engineering. 2025, 45(4): 168-174. https://doi.org/10.3969/j.issn.0253-6099.2025.04.031
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The additive manufacturing of SiCp/Al606 by photocuring process was studied, and the effects of resin monomer and solid volume fraction on the stability, rheological properties and photocuring performance of SiCp/Al6061 slurry, as well as the compactness and microstructure of sintered product were explored. The results show that as photosensitive resins of PEG200DA and PEG400DA mixed at an appropriate ratio of 1∶1, the prepared slurry with content of 52.5%, viscosity of 5.05 Pa·s (shear rate of 10 s-1) and single-layer curing thickness of 100.3  μm can meet the requirements for photocuring in additive manufacturing. The SiCp/Al component manufactured by photocuring process can have a complete structure and good interlayer bonding, and the sintered product with no cracks and obvious necking presents relatively high compactness (94.07%).
  • Surface Descaling and Cleaning Process for High-End Plates
    HUANG Haihua, KE Yi, MAO Guiting, HAN Dekui, OUYANG Dengpei, GAO Bo
    Mining and Metallurgical Engineering. 2025, 45(4): 175-179. https://doi.org/10.3969/j.issn.0253-6099.2025.04.032
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To improve the surface quality of high-end plates by descaling and cleaning process, an experimental study was carried out with different process routes that are determined based on the combination of Steel Eco Descaling (SED) technology and other surface pretreatment processes. Based on the analysis of surface appearance, surface roughness, surface micromorphology and surface energy spectrum of the plates treated by different processes, an optimal descaling process is finally determined, consisting of SED, soaking with roller brush cleaner, polishing with scouring pad buffering wheel, and high-pressure flushing. After cleaning treatment with this process, the plate sample is overall in a uniform metallic color, with significantly reduced surface roughness and oxygen content. It is concluded that after treatment with this combined process, surface quality of the third-generation advanced high-strength steel (AHSS) plates for automotive can be effectively improved.
  • Finite Element Analysis of Electron Beam Welding Performance of TU2 Oxygen-Free Copper
    YIN Zhonghui, WANG Huichun, WANG Shaoqiu, MA Jianguo, LIU Zhenfei
    Mining and Metallurgical Engineering. 2025, 45(4): 180-185. https://doi.org/10.3969/j.issn.0253-6099.2025.04.033
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For reducing energy consumption while ensuring weld joint quality, the welding process parameters for electron beam welding of TU2 oxygen-free copper were optimized with SYSWELD simulation software, and a finite element model with appropriate boundary conditions was established for a 30-mm-thick TU2 copper plate. A heat source model was determined based on the actual situation of electron beam welding, and simulation analysis was made by imputing varied energy consumption value in the welding process, with the obtained simulation results compared with actual welding results. It is shown that with a double-ellipsoidal heat source input of 1260 J/mm and a 3D Gaussian heat source input of 5000 J/mm, a full penetration weld with the lowest energy consumption can be achieved. The simulation results show that the obtained morphology of molten pool is almost the same with that in the actual welding, proving that the welding parameters set in the simulation analysis are feasible for TU2 welding. It is concluded that this study can provide a reliable reference for optimizing the parameters in welding of TU2 oxygen-free copper.
  • Effect of Ferrite Content and Distribution on Microstructure and Properties  of Ultra-high Strength Martensite-Ferrite Dual-Phase Steel
    QIAN Yajun, LIU Wenjian
    Mining and Metallurgical Engineering. 2025, 45(4): 186-191. https://doi.org/10.3969/j.issn.0253-6099.2025.04.034
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Martensitic steel with different ferrite content and distribution was firstly fabricated by heat treatment. Then, the effects of ferrite content and distribution on the microstructure and properties of such ultra-high strength martensitic steel with yield strength more than 1100 MPa was explored based on microstructure characterization and mechanical property tests. The microstructure evolution and strengthening and toughening mechanism were also analyzed. The results show that with a small amount of ferrite uniformly distributed in the martensite matrix, the steel sample in the experiment can exhibit not only ultra-high yield strength (1245.44 MPa) and tensile strength (1411.96 MPa ), but also higher impact energy (80 J) at low temperature, presenting the optimal comprehensive mechanical properties. A small amount of ferrite in the local area continuously distributed  along the rolling direction can slightly improve the tensile strength, but the unevenly distributed  ferrite can improve the stress concentration and reduce the toughness. An increase in the content of continuously distributed ferrite can improve the tensile strength, but the formation of banded martensite and improved stress concentration make the toughness of the steel sample in the experiment substantially reduced.
  • Effect of Annealing Temperatures on Fatigue Properties of Al-Cu-Mg-Ag Alloys
    LAI Zhiwei, LIU Zhiyi, BAI Song, HE Guangyu
    Mining and Metallurgical Engineering. 2025, 45(4): 192-195. https://doi.org/10.3969/j.issn.0253-6099.2025.04.035
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Effect of annealing temperature on the mechanical properties and fatigue properties of Al-Cu-Mg-Ag alloy was explored by preforming fatigue crack propagation (FCP) rate testing, room-temperature tensile test and using characterization means such as X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the T4 state specimen annealed at 420 ℃ for 4 h presents higher yield and tensile strength, but poor plasticity. As the annealing temperature increases within the range of 400-430 ℃, the orientation density of the Goss texture in the alloy first increases and then decreases, and the T4 specimen after 4 h annealing at 420 ℃ presents an optimal fatigue performance, with lower FCP rate around 1.34×10-3 mm per cycle at ΔK≈20 MPa·m0.5.
    • BUSINESS ECONOMY AND MANAGEMENT
  • Two-Way Empowerment of Low-Altitude Economy andMining and Metallurgical Engineering: Coupling Mechanism of Technology Chain and Talent Chain
    XU Peng, HE Yueguang
    Mining and Metallurgical Engineering. 2025, 45(4): 196-200. https://doi.org/10.3969/j.issn.0253-6099.2025.04.036
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A discussion on collaborative development of low-altitude economy (LAE) and mining & metallurgical engineering (MME), as well as the two-way empowerment mechanism is presented. Low-altitude technologies, such as unmanned aerial vehicle (UAV) and electric vertical take-off and landing aircraft (eVTOL), can be used to reshape MME, while MME can provide core materials for low-altitude aircraft. However, the collaboration between them is limited by disciplinary barriers and talent gaps, so it is necessary to build a dual system of “technology chain-talent chain”. This can be achieved by adding interdisciplinary courses, establishing actual flight certification bases in mining areas, promoting  integration of relevant qualification certifications, and accelerating  incubation of key technologies based on low-altitude economic industrial parks. These measures can break down discipline barriers, shorten the cycle of technology transformation, and provide support for the in-depth integration and collaborative development of LAE and MME.
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