This study introduces a multilayer perceptron artificial neural network model to predict water split, cut size and sharpness of separation in hydrocyclone classifiers. The model is developed based on experimental data from 75, 100, 150 and 250 mm diameter hydrocyclones under different operating conditions and design parameters. The Levenberg-Marquardt training algorithm is found to be optimal based on the correlation coefficient and mean square error values. Pearson's correlation coefficient is used to assess the strength and direction between variables. The importance of input variables is estimated using the out-of-bag permuted predictor method. The ANN model employs 10, 10 and 8 hidden neurons achieving regression coefficients of R similar to 0.92, R similar to .99, R similar to 0.90 and MSE values of 21.98, 38.915, 0.34 for water split, cut size and sharpness of separation, respectively. Comparative analysis indicates that the ANN model shows superior performance than empirical and semi empirical models.
This article investigated the recoverability of the Ga in bauxite by carbothermal reduction. Currently, Ga is mostly manufactured from bauxite through the Bayer process as a by-product of alumina, but it is worthwhile to consider alternative processes under stricter environmental regulations and a shortage of high-quality bauxite. This study focused on the Pedersen process, which is the alumina production process consisting of carbothermal reduction and alkaline leaching. The metal and slag phases were prepared by carbothermal reduction of bauxite at 1873 K, and then aluminium in the slag was leached with (Na2CO3 + NaOH) solution at 348 K. Evaluation by inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry revealed that almost all Ga in bauxite was transferred to the metal phase, and the distribution to the slag phase was negligible in carbothermal reduction, which agrees with the thermodynamic consideration. These results suggest that the gallium recovery from pig iron is necessary to produce Ga in the Pedersen process.
The manufacture of phosphate fertilizers without prior uranium extraction leads to widespread dispersal of uranium compounds across agricultural fields, posing significant cumulative environmental and health risks. Furthermore, this represents a wasteful loss of a critical global energy resource. Against this backdrop, we propose an environmentally friendly method for extracting uranium from Egyptian Abu Tartur phosphate rocks using humic acid (HA). Almost complete dissolution of uranium with a 3% HA concentration, solid-to-liquid ratio of 1/2, and a leaching temperature of 60°C. The uranium was then effectively adsorbed from the HA solution, with a concentration of 0.026 g/L, onto activated carbon, influenced by variables such as: pH, contact time, and adsorbent amount per leach solution volume. Subsequent uranium regeneration from the activated carbon was accomplished using 0.5 M ammonium bicarbonate, achieving a desorption efficiency of 98.7%. This process culminated in the production of a sodium diuranate concentrate following uranium precipitation with NaOH solution.
In this work, the biomass charcoal from rubber wood, coconut shell, corn cob, palm kernel shell, as a reductant in the smelting process of saprolitic nickel laterite has been observed in a laboratory submerged arc furnace. A total of 5 kg of saprolite, some reductant and limestone were smelted together in this furnace, which was adjusted to 0.8 of carbon stoichiometric and 0.8 of slag basicity. The smelting process was carried out for 1 h, and the pouring temperature was 1400 degrees C-1500 degrees C. From the result, the smelting process using corn cob charcoal and palm kernel shell charcoal showed almost similar nickel grade and recovery compared with using coke as a reductant, which is above 12% and 90%, respectively. It also has the same slag phase, that is, diopside, with a low melting point. These two types of biomass waste reductants could be replaced using coke in the future.
Artisanal and small-scale gold mining (ASGM) faces challenges in accessing capital, technology, and responsible practices, hindering sustainable operations and contributing to environmental and health impacts from mercury use. This study evaluated optimizing direct smelting of gold concentrates as an alternative to mercury amalgamation for efficient and responsible production. 50 kg of ore from Nholi mine was concentrated using a Knelson concentrator and analyzed (XRF, fire assay with AAS, XRD). Response surface methodology with a face-centered composite design investigated smelting temperature (1100–1400 °C), duration (30–90 min), and concentrates-to-flux ratio (1:1–3:1) effects. The impact of sulfide concentration (pyrite varied 6.7–48%) on gold recovery was explored. Low-sulfide concentrates associated with pyrite and sphalerite yielded best recovery (>80%) at 1250 °C for 90 min with 2:1 concentrates-to-flux ratio. Direct smelting with ≤6.7% sulfide enabled over 87% gold recovery, facilitating responsible ASGM production.
In the current study, elemental analysis and microscopic investigations were conducted to characterize the minerals present in an iron ore sample. The iron content was below 24%, with the dominant iron-bearing minerals being hematite and magnetite. Consequently, gravity and magnetic separation methods were employed to enhance the iron content. However, the processing results less than what was expecting due to incomplete sample characterization. The sample was further analyzed using quantitative X-ray diffraction analysis. This more comprehensive examination revealed additional iron-bearing minerals as goethite, ankerite, and limonite. The behavior of these minerals likely contributed to the unsuccessful separation process which was thoroughly explored in this article. Understanding the mineralogical composition of iron ores is paramount for optimizing processing operations and achieving successful outcomes.
Two billion tons of iron ore is mined globally/year, still, a comprehensive protocol for obtaining discrete element method parameters is missing. A slight improvement in operational difficulties can translate into significant financial benefits. A direct measurement of discrete element method interaction parameters, such as sliding and rolling friction and cohesion energy between a pair of particles, is very difficult. Therefore, a bulk calibration approach is used to obtain discrete element method parameters that involve performing laboratory scale tests (angle of repose, wall friction angle, etc.), which are subsequently reproduced in the discrete element method model and adjusted through a novel, sequentially coupled central composite experimental design. Results are demonstrated through simulations of 14.5 wt-% moisture-containing iron ore (representing the most difficult scenario) flow through an industrially operational transfer chute. Four different liner materials were investigated. Interestingly, cohesion and frictional forces are found to be flow-determining rather than inertial forces, and the nature of the liner plays the most significant role.
The study on the technology of producing neodymium metal using the calciothermic reduction process is reported in this article. The process primarily involves the conversion of neodymium oxide (Nd2O3) into neodymium fluoride (NdF3) followed by the reduction of neodymium fluoride to neodymium metal using calcium as reductant. Fluorinating conditions were standardised to obtain the desired product (NdF3) free of any unwanted impurities. The calciothermic reduction of the resulting neodymium fluoride was studied in detail to establish the reduction conditions to achieve maximum yield and purity of the neodymium metal. This process obtained the neodymium metal with a purity of 99.6% before refining step.
This study develops an intelligent data-driven approach for optimising slag grinding systems. Slag grinding exhibits complex nonlinear dynamics that challenge control. The proposed system monitors key operating parameters to assess machine health and automate control adjustments. Operating data are collected, and features linked to health status are identified using data mining techniques. Cluster analysis categorises historical data into healthy/unhealthy modes to build a condition library. Real-time data are then evaluated against this library. A predictive model forecasts future trend. The system was implemented in an industrial slag mill. Results demonstrated reduced vibration and energy use versus manual control. Validation confirmed improved accuracy in predicting mill responses. Significant energy savings were achieved annually through optimised control. The system enhances safety by automating adjustments while minimising costs and environmental impacts. Data-driven strategies overcome the limitations of traditional methods, representing an advance for intelligent management of industrial processes. Benefits were confirmed through rigorous factory implementation and performance monitoring.
In this study, the recovery of copper from ammonia–ammonium chloride (NH3–NH4Cl) leach liquor using sterically hindered beta-diketone (β-diketones), a well-known extractant, was investigated. The experimental approach entails studying how various factors, including extraction time, concentration of the extractant, pH, phase ratio, and temperature, impact the effectiveness of copper extraction. The most favourable conditions for extracting copper from ammoniacal solutions containing 871.27 mg/L Cu2+, 1.75 mol/L NH3, and 0.5 mol/L NH4Cl were determined. Optimal copper extraction was achieved through a one-stage solvent extraction process at a phase ratio of 1 : 1, utilising sulphonated kerosene containing 0.25 mol/L of β-diketones. This extraction process lasted for 10 min and yielded a copper extraction efficiency of 75.10%. Additionally, a stripping ratio of 98.52% was achieved from the loaded organic phase through a one-stage stripping procedure at a phase ratio of 1 : 1, conducted at a temperature of 298 ± 0.5 K.
The study focused on leaching complex copper–cobalt oxide ore from Zebesha Mine in Zambia. The chemical analysis indicated the presence of cobalt, copper, nickel, manganese and iron as base metals. Copper is predominantly found in malachite and a small portion in heterogenite mineral along with cobalt, iron, manganese and nickel. The leaching process involved using solutions containing iron: ferrous sulphate, FeSO4·7H2O; ferrous ammonium sulphate, (NH4)2Fe(SO4)2·6H2O; and ferric sulphate, Fe2(SO4)3. The effects of temperature and salt concentrations were studied alongside metal content determination through titration-atomic absorption spectroscopy techniques. It was observed that the preferential dissolution of copper occurred with Fe2 (SO4)3 while temperatures above 70°C leaching with FeSO4·7H2O resulted in the recovery of over 80% of manganese and cobalt. This study suggests that ferrous containing lixiviants can effectively promote the manganese and cobalt dissolution but are not efficient for extracting copper. Furthermore, using Fe2(SO4)3 may allow for selective leaching of copper.
This study introduces a multistage hydrometallurgical process designed for the recovery and individual separation of Nd and Pr from NdFeB magnet scrap. Following demagnetization, the magnet underwent crushing, grinding, and leaching using a sulfuric acid solution. The pH of the resultant leachate was subsequently adjusted to 1.2 using a NaOH solution, leading to the precipitation of Nd and Pr as sodium double sulfates. The produced double sulfate was then mixed with a saturated NaOH solution, resulting in the formation of rare earth hydroxide. The hydroxide was further decomposed into oxides (REO) after calcination at 500°C. The REO was dissolved in hydrochloric acid and nitric acid solutions to investigate the individual separation of Nd and Pr using the D2EHPA–TOA extractant system and compare the results with D2EHPA-only system. It was concluded that the extraction mechanism of D2EHPA–TOA system is highly dependent on the acidity of the solution, with TOA having a synergistic effect on the REE extraction when pH > 3, and an antagonistic effect when pH ≤ 3. In terms of extraction efficiency, both extractant systems demonstrated efficiency levels exceeding 99% when the pH was ≥2, with similar behavior when extraction was performed in HCl and HNO 3 media. Although both extractant systems yielded unsatisfactory outcomes in the separation of Nd and Pr, a marginal improvement was observed with the incorporation of TOA into the extractant system. This observation implies the potential of exploring analogous combinations in future studies.
In this study, the effects of truncated ellipsoids and cubes on the particle size distribution of a UG2 ore were compared to the spheres using the response surface methodology for experimental design, modeling, and optimization. The response surface methodology demonstrated that it can be useful in optimizing grinding operations. It provides lenses to see and analyze the behavior of the ball filling, interstitial filling, and % solids parameters which are complex and interactive, and their effects on the production of the desired product (−75 µm) for different grinding media. Spherical grinding media outperformed truncated ellipsoids and cubes, producing the highest amount of the desired size class (82.58%), followed by 80.41% for truncated ellipsoids and 77.07% for cubes. Spheres also consumed the least power followed by cubes and lastly truncated ellipsoids. The differences in optimal grinding conditions were attributed to different contact mechanisms, surface area, and load behavior of the grinding media.
Blast furnace (BF) operation depends on the smooth upward movement of gas and its pressure drop. The slag properties like viscosity affects the gas flow inside the furnace. It is well-known that Al 2 O 3 contributes to the increase of slag viscosity. For smooth BF operation, the maximum limit of Al 2 O 3 in the Indian BF slag is around 18.5%. Higher Al 2 O 3 contents make tapping of the BF slag difficult. In the present work, FACTSAGE calculations were carried out to estimate the viscosity and melting temperature of 20% Al 2 O 3 slag varying MgO% between 7 and 13 and basicity (B2, defined as wt% CaO/wt % SiO 2 ) between 0.9 and 1.2 to find an optimum MgO% and basicity for easy tapping of the slag. The results of the calculations provide three combinations of MgO (12,12.5,13%) and B2 (0.95) of slag for operating 20% Al 2 O 3 in slag which were validated through experimental studies involves the inclined plane test, hot stage microscopy and X-ray diffraction.
In 2025, it is projected that global sales of battery-based electric cars (electric vehicle [EV]) will reach 145 million units, exceeding those of fuel vehicle-based cars (internal combustion engine [ICE]), so that in the future the demand for electric batteries (EBs) will be even greater. In managing the large nickel resources as raw material for electric vehicle batteries, new policies, and breakthroughs are needed so Indonesian electric vehicle batteries have high competitiveness in facing the global market. This study aims to analyse the condition of the electric vehicle battery industry sector in the global competitive arena, which consists of 14 countries with the world’s largest nickel resources and reserves. The results of the analysis show that, first, it is necessary to master technology and utilise qualified and professional human resources. Second, increasing the availability of supporting infrastructure for the establishment of electric vehicle battery factories, as well as improving the quality of electric vehicle batteries so that they are highly competitive to seize global market opportunities. The analysis can be used as input for the government to improve the competitiveness of electric vehicle batteries in facing the global market and the fulfilment of nickel needs for the domestic electric vehicle battery industry.
Cyanidation is the most widely used technique for gold extraction worldwide. However, its efficiency in gold extraction has decreased due to gold association with base metals such as copper. Copper is known to form different complexes with cyanide depending on the pulp pH. These Cu-CN complexes deplete the pulp of free cyanide, thereby decreasing gold leaching. The study examined the application of diethylenetriamine (DETA) in cyanidation to minimise copper ions effect on gold cyanidation. Leaching tests performed in the presence of copper ions reduced gold recovery from 93% to 15% at a copper sulphate concentration of 1% and increased cyanide consumption by 10%. The introduction of DETA (between 0.2% and 1%) however restored gold recovery back to normal as the baseline without copper ions and also enabled gold extraction at a reduced cyanide strength. Based on the study, DETA could be used during gold-copper cyanide leaching to minimise the copper ion effect and enhance gold extraction.
This review discusses the electrochemical principles involved in the recovery of metals from aqueous solutions and fused salt electrolytes. In this article we concentrate on electrolytic processing of different types of metals with an emphasis on the significant role of electrochemical principles together with free energy and activity in electrowinning and electrorefining of common and reactive metals. Based on discharge potentials, metals are classified into three categories with respect to their characteristics of deposition from aqueous electrolytes without hydrogen evolution, under hydrogen over-voltage, and only from fused electrolytes.
