Low-grade Manganese Ore Research Articles

Modeling and optimization of low-grade Mn bearing ore leaching using response surface methodology and central composite rotatable design

The application of leaching process to extracting Mn from a low-grade manganese ore was investigated using a software based design of experiments. Four main parameters, i.e. sulfuric acid concentration, oxalic acid concentration, time and temperature were considered in a central composite response surface design. The recoveries of Mn and Fe were selected as response of design. The optimum conditions under which the Mn and Fe recoveries were the highest and the time and temperature were the lowest were determined using statistical analysis and analysis of variance (ANOVA). The results showed that Mn and Fe recoveries were 93.44% and 15.72% under the optimum condition, respectively. Also, sulfuric acid concentration was the most effective parameter affecting the process. The amounts of sulfuric and oxalic acid were obtained to be 7% and 42.50 g/L in optimum condition and the best time and temperature were 60 min and 65°C.

Reductive leaching of pyrolusite ore by using sawdust for production of manganese sulfate

Manganese compounds, such as manganese sulfate, can be obtained from pyrolusite, a manganese ore. Low-grade manganese ores is usually treated by hydrometallurgical methods. In this study, the leaching and recovery of manganese from pyrolusite ore in sulfuric acid solutions containing sawdust as reducing agent was investigated. The effects of experimental parameters, such as sulfuric acid concentration, sawdust amount, solid-to-liquid ratio, stirring speed, particle size, reaction temperature, and leaching time, on the manganese extraction from ore were examined. The results showed that the leaching rate of pyrolusite ore increased with an increasing sulfuric acid concentration, sawdust amount, stirring speed, reaction temperature and leaching time, and decreasing in solid to liquid ratio and particle size. The kinetic analysis of leaching process was carried out, and it was determined that the reaction rate was controlled by diffusion through the product layer under the experimental conditions in this work. The activation energy was found to be 22.35 kJ mol−1. Manganese can be recovered as manganese sulfate by the evaporative crystallization of the purified leach liquor.

Microbial Recovery of Manganese using <i>Staphylococcus Epidermidis</i>

Manganese minerals are widely distributed throughout the globe. The most important industrial uses of Mn are in the manufacture of steel, non-ferrous alloys, carbon-zinc batteries and some chemical reagents. Microbial recovery of manganese from low grade manganese ores using bioleaching was investigated in this paper. A bacterial strain, Staphylococcus epidermidis (MTCC-435) was collected from microbial type culture collection, IMTECH Chandigarh and used for the experiment. The experimental results for bioleaching with S. epidermidis showed that under pH 5.5, particle size –150 μm, pulp density 10%, temperature 35℃ and agitation 200 rpm, about 80% of Mn was recovered within 20 days of incubation.

Reductive Acid Leaching of Low Grade Manganese Ores

Manganese recoveries from low-grade ores using organic acids as reducing agents were investigated in the present work. The acid leaching potential of both oxalic acid and citric acid were estimated. Manganese leaching amount were measured by using standard manganese curve and estimated by titration method. Effects of various acid concentrations on leaching efficiency were studied. The observed result suggested prominent manganese recovery of 66% by oxalic acid at 2 M concentration whereas citric acid had less effect on leaching showing leaching percentage upto 40% in 6 days. Acid leaching of manganese ore with both the acids gave a comparative data stating that oxalic acid leached better than citric acid.

Investigation on the Beneficiation of Low-Grade Manganese Ore in Sichuan

Flotation, magnetic separation and leaching experiments have been carried out for the beneficiation of low-grade manganese ore. The results indicated that flotation and magnetic separation could improve the grade of Mn concentrate while the recovery was lower. Better recovery of Mn could be achieved by leaching on optimum conditions, 91.78% of Mn could be recovered by 30 minutes leaching with 25g of sulphuric acid at the liquid/solid ratio of 3:1.

Beneficiation and agglomeration process to utilize low-grade ferruginous manganese ore fines

Characterisation, beneficiation and agglomeration studies were carried out to develop a utilization strategy for typical Indian low grade manganese ore fines. The major mineral phases found are pyrolusite, hematite, goethite, clay, feldspar and quartz. QEMSCAN and Sink–Float studies suggested that 40% of manganese minerals are in liberated form, whereas 30% are locked with iron minerals. Classification followed by two-stage high intensity magnetic separation (1.7 & 1.1 Tesla) process can recover 35–40% material of ferromanganese grade with 47–49% Mn recovery. The recovered material was briquetted adding molasses (7%), cement (3%) and bentonite (1%) to use in the submerged arc furnace for metallurgical applications. A cost effective process flow sheet has been developed to utilize these fines.

Pb(II), Cd(II) and Zn(II) adsorption on low grade manganese ore

Low grade manganese ore (LMO) of Orissa containing 58.37% SiO2, 25.05% MnO2, 8.8% Al2O3, and 5.03% Fe2O3 as the main constituents was taken to study its adsorption behaviour for Pb(II), Cd(II) and Zn(II) from aqueous solutions. The XRD studies showed the crystalline phases to be quartz, ß-MnO2, d-MnO2 and Fe2O3. Batch adsorption studies were carried out by varying the experimental parameters which included contact time, pH, adsorbate and adsorbent concentrations and temperature. The time data fitted well to pseudo second order kinetics for Pb(II), Cd(II) and Zn(II) adsorption. With the increase in adsorbent dose, loading capacities decreased. With the increase in pH from 2.0 to 5.5, Pb(II) adsorption increased while Cd(II) and Zn(II) adsorption increased till an initial pH of 3.0. Positive ?H° values confirmed the adsorption process to be endothermic and positive ?S° values suggest the increased randomness at the solid-solution interface during the adsorption of cations on the sample. The adsorption data showed good fit to both Langmuir and Freundlich isotherm models for the three cations. The Langmuir monolayer capacities for Pb(II), Cd(II) and Zn(II) were estimated to be ~142.85, 59.17 and 98.0 mg per gram of LMO sample respectively. From the XRD studies of loaded samples, it was observed that Pb((II) adsorption affects silica phase whereas Cd(II) adsorption affects both silica and ß-MnO2 phases. With Zn(II) adsorption both the intensity and peak position of silica phase were disturbed. From the electron probe micro analysis (EPMA) it was observed that Pb(II), Cd(II) and Zn(II) adsorption are more prone to silica, iron oxide and ß-MnO2 phase respectively though their distribution in other phases was also marked but to a lesser extent. Due to high loading capacities obtained for Pb(II) and Zn(II), low grade manganese ore can be regarded as a potential adsorbent for these metals. Keywords: Low grade manganese ore, adsorption, Pb(II), Cd(II), Zn(II), EPMA

Kinetics of reductive leaching of manganese oxide ore with molasses in nitric acid solution

The kinetics of reductive leaching of manganese from a low grade manganese ore in dilute nitric acid in the presence of molasses is examined. The rate is controlled by diffusion through the “product” layer composed of the associated minerals. The leaching process follows the kinetic model 1 − 2/3 X − (1 − X) 2/3 = kt with an apparent activation energy of 25.7 kJ/mole. It is concluded that the concentration of HNO 3 and molasses as well as temperature are the main factors influencing the leaching rate. The results indicate a reaction order of 1.2 for HNO 3 concentration and 1.9 for molasses concentration.

Analyzing Leaching Data for Low-Grade Manganese Ore Using Neural Nets and Multiobjective Genetic Algorithms

Existing acid leaching data for low-grade manganese ores are modeled using an evolving neural net. Three distinct cases of leaching in the presence of glucose, sucrose and lactose have been considered and the results compared with an existing analytical model. The neural models are then subjected to bi-objective optimization, using a predator–prey genetic algorithm, maximizing recovery in tandem with a minimization of the acid concentration. The resulting Pareto frontiers are analyzed and discussed.

Enrichment of Cobalt Values by Dry Magnetic Separation from Low-Grade Manganese Ores of Bonai-Keonjhar Belt, Orissa

Resource potential of cobalt in India is practically negligible. Cobalt in marine manganese nodule though known since long, its report from terrestrial manganese ore is least observed. This paper reports the occurrence of cobalt in low-grade manganese ores of Bonai-Keonjhar belt, Orissa, eastern India and describes methods for its possible enrichment. Cobalt is associated with manganese minerals like lithiophorite (~CoO: 1.2%) and cryptomelane (~CoO: 0.2%). A feed of low-grade siliceous manganese ore containing 26% Mn and 32% SiO2 and 0.08% Co was subjected to physical beneficiation. By processing the low-grade siliceous ore on a dry belt magnetic separator, a product with 47% Mn at 60% recovery could be obtained. It was observed that along with manganese the cobalt value gets enriched (~Co: 0.38%) more than four times in comparison to the feed. Some other traces like Ni, Cu, Zn, Ga, Li etc. also get enriched in the magnetic product. Thus, through simple dry magnetic separation a low-valued material cannot only be converted to usable product but two valuable metals can also be recovered from it.

Multiobjective Optimization of Manganese Recovery from Sea Nodules Using Genetic Algorithms

Treatment of low grade manganese ores is receiving widespread attention due to major use of manganese (85–90%) as ferromanganese alloy in the rapidly growing iron and steel sector and also in other important industrial products like electrolytic manganese dioxide (EMD) used in the energy sector. Manganese bearing polymetallic sea nodules containing less than 40% Mn fall in the category of lean grade ores and besides manganese these nodules are the reserve for other metals like copper, nickel, and cobalt. In this present work, treatment of these polymetallic sea nodules in an acid-based hydrometallurgical route has been proposed using two different schemes, batch and parallel in nature. Both processes have been optimized using multiobjective genetic algorithms.

Reducing acid leaching of manganiferous ore: Effect of the iron removal operation on solid waste disposal

The process of reducing acid leaching of manganiferous ore is aimed at the extraction of manganese from low grade manganese ores. This work is focused on the iron removal operation. The following items have been considered in order to investigate the effect of the main operating conditions on solid waste disposal and on the process costs: (i) type and quantity of the base agent used for iron precipitation, (ii) effective need of leaching waste separation prior to the iron removal operation, (iii) presence of a second leaching stage with the roasted ore, which might also act as a preliminary iron removal step, and (iv) effect of tailings washing on the solid waste classification. Different base compounds have been tested, including CaO, CaCO3, NaOH, and Na2CO3. The latter gave the best results concerning both the precipitation process kinetics and the reagent consumption. The filtration of the liquor leach prior to iron removal was not necessary, implying significant savings in capital costs. A reduction of chemical consumption and an increase of manganese concentration in the solution were obtained by introducing secondary leaching tests with the previously roasted ore; this additional step was introduced without a significant decrease of global manganese extraction yield. Finally, toxicity characteristic leaching procedure (TCLP) tests carried out on the leaching solid waste showed: (i) a reduction of arsenic mobility in the presence of iron precipitates, and (ii) the need for a washing step in order to produce a waste that is classifiable as not dangerous, taking into consideration the existing Environmental National Laws.

Reductive leaching of manganese from low-grade manganese ore in H 2SO 4 using cane molasses as reductant

Manganese extraction from a low-grade ore was investigated using cane molasses as a reducing agent in dilute sulfuric acid medium. The effects of concentrations of cane molasses and sulfuric acid, leaching temperature as well as reaction time were discussed. The results showed that high manganese recovery with low Fe and Al extraction yield could be obtained by analyzing the leaching efficiencies of Mn, Fe and Al during the leaching process. The optimal leaching condition was determined as 1.9 mol/L H 2SO 4 and 60.0 g/L cane molasses for 120 min at 90 °C while using particles smaller than 0.147 mm. The leaching efficiencies were 97.0% for Mn, whereas 21.5% for Al and 32.4% for Fe, respectively.

Leaching of manganese ores using sawdust as a reductant

In this study sawdust was used as reductant for sulphuric acid leaching of manganese ore. Effects of pulp density, amount of acid, temperature, particle size of ore and amount of sawdust were studied. Manganese extraction of ∼98% was achieved under the conditions: leaching time 8 h, 5% H 2SO 4 (v/v), 10% pulp density, 90 °C and 5% sawdust (w/w), i.e. 0.5 g/g ore. Other Mn containing materials like low grade manganese ore, manganese nodule and Mn-nodule leach residues were tested and all these materials responded well giving more than 98% Mn extraction.

Manganese metallurgy review. Part I: Leaching of ores/secondary materials and recovery of electrolytic/chemical manganese dioxide

The world rapidly growing demand for manganese has made it increasingly important to develop processes for economical recovery of manganese from low grade manganese ores and other secondary sources. Part I of this review outlines metallurgical processes for manganese production from various resources, particularly focusing on recent developments in direct hydrometallurgical leaching and recovery processes to identify potential sources of manganese and products which can be economically produced.High grade manganese ores (>40%) are typically processed into suitable metallic alloy forms by pyrometallurgical processes. Low grade manganese ores (<40%) are conventionally processed by pyrometallurgical reductive roasting or melting followed by hydrometallurgical processing for production of chemical manganese dioxide (CMD), electrolytic manganese (EM) or electrolytic manganese dioxide (EMD).Various direct reductive leaching processes have been studied and developed for processing low manganese ores and ocean manganese nodules, including leaching with ferrous iron, sulfur dioxide, cuprous copper, hydrogen peroxide, nitrous acid, organic reductants, and bio- and electro-reductions. Among these processes, the leaching with cheap sulfur dioxide or ferrous ion is most promising and has been operated in a pilot scale. The crucial issue is the purification of leach liquors and the selective recovery of copper, nickel and cobalt is often difficult from solutions containing soluble iron and manganese. For treatment of manganese bearing materials including waste batteries, spent electrodes, sludges, slags and spent catalysts, a leaching or reductive leaching step is generally needed followed by various purification steps, which makes the processes less economically viable.It is concluded that the recovery of manganese from nickel laterite process effluents which contain 1–5 g/L Mn offers a growing low cost resource of manganese. Part II of this review considers the application of various solvent extraction reagents and precipitation methods for treating such manganese liquors.

Synthesis and magnetic properties of manganese ferrite from low grade manganese ore

Manganese ferrite MnFe 2O 4 powders have been produced from low grade manganese ore after leaching of the ore in sulfuric acid and hydrogen peroxide. The produced solution was precipitated by using 5 M sodium hydroxide until pH 9–12 after correction Fe:Mn mole ratio to 2:1 using waste ferrous sulfate from iron and steelmaking. The produced precursors were thermally treated at temperature from 600 to 1200 °C. Effects of calcination temperature, calcination time and pH on the manganese ferrite phase formation and magnetic properties were studied. The results showed that a well-defined manganese ferrite crystal phase was formed when the calcination temperature increased to 1000–1200 °C. The maximum saturation magnetization (27.24 emu/g) was achieved at calcination temperature 1000 °C, calcination time 120 min and pH 10.

A Comparative Study on Acid Leaching of Low Grade Manganese Ore Using Some Industrial Wastes as Reductants

AbstractLocal pyrolusite ore from Om‐Bogma, Sinai, has been treated by sulfuric acid leaching process using either sawdust (C6H10O5)n or lactose (C12H22O11) as reducing agent to produce manganese sulfate. The manganese recoveries were 92.5 and 90.5% at sawdust and lactose respectively.

Leaching of low-grade manganese ores by using nitric acid and glucose: optimization of the operating conditions

Manganese extraction from low-grade ores was investigated by using glucose as a reducing agent in dilute nitric acid medium. Ore characterisation by X-ray and SEM denoted that manganese is present as a mixed oxide Mn 7O 13 (6MnO 2·MnO) surrounding and joining together aluminosilicate fragments. The effects of temperature, particle size, glucose and nitric acid concentrations were investigated and compared with previous results using H 2SO 4. The operating conditions of leaching were optimised to obtain maximum manganese extraction and purity by performing sequential factorial designs and evaluating the statistical significance of the different factors by analysis of variance (ANOVA). The optimised conditions are 90 °C, stoichiometric nitric acid, −20% below stoichiometric glucose and 295–417 μm size fraction. The stoichiometric reagent concentrations were evaluated according to the following reaction assuming all manganese in the ore as Mn(IV): C 6H 12O 6+12MnO 2+24H +=6CO 2+12Mn 2++18H 2O Optimised leaching conditions with HNO 3 give up to 99% manganese extraction, <0.05% iron dissolution and reduced reagent consumption compared to previous tests using H 2SO 4.

Laboratory study: simultaneous leaching silver-bearing low-grade manganese ore and sphalerite concentrate

Rich silver-bearing low-grade manganese ore can be found in great supply in China's Yunnan Province. This paper describes an experiment in which silver-bearing low-grade manganese and sphalerite concentrate were leached and manganese, silver and zinc recovered. First the chemical composition and mineralogical structure of silver-bearing low-grade manganese ore were determined. Then, by studying the effects of adding amounts of reducing agents and sulfuric acid as well as reaction time, the temperature and the liquid-to-solid ratio on the leaching process, optimum technological conditions were achieved. The leaching rate of manganese reached 98%. The silver in the slag was leached by adding an ammonia solution. By adding hydrazine hydrate, sponge silver with purity of up to 99% was obtained. The recovery rate of silver reached 87%.

Mechanism of Reduction in an Oxygen Reactor for Ore–Coal Pellets Prepared with Low-Grade Manganese Ore

Mechanism of Reduction in an Oxygen Reactor for Ore–Coal Pellets Prepared with Low-Grade Manganese Ore