Raw Ore Research Articles

Effect of microwave radiation on the magnetic properties of ludwigite and iron-boron separation

To effectively separate and recover the valuable elements iron and boron from ludwigite, this study investigated the magnetic properties and the magnetic separation efficiency. And the reactivity of boron component in the B-bearing tailing was studied. The results indicated that the saturation magnetization of ore samples was increased with the increase of microwave power and heating time. Under condition of 40 s with 4 kW, the saturation magnetization of ore samples increased from 12.73 emu/g for the raw ore to 24.70 emu/g for the treated ore, an increased of 94.03%. After magnetic separation, the grade and recovery rate of iron in the iron concentrate and the boron grade in the tailing for the treated sample with 4 kW for 40 s were increased by 19.74%, 31.46% and 86.46% in comparison with those of the untreated ore. The sample was heated to 600 °C at 4 kW and held for 20 min, the reactivity of boron component in the B-bearing tailing reached 86.68 wt%, which increased by 34.01% compared with that of the raw ore and 4.43% compared with that of the optimal traditional roasting value at 700 °C for 2 h, indicating that the roasting temperature and time were obviously decreased and the reactivity was significantly improved by the microwave radiation.

Isolation and Molecular Characterization of Two Bacterial Strains with Higher Bioleaching Potentials, from Agbaja Mines (Kogi State, Nigeria)

Bacterial strains with higher bioleaching capacity (BC) are relevant for the mining industry, being more eco-friendly methods, for instance more than cyanide based extraction. Microbiological samples were collected from selected sites in Agbaja Mines, which after a growth enrichment step, cultures were screened for iron BC, including chemical quantification of iron species. Strains with the highest BC were morphologically, biochemically and molecularly characterized. Two bacterial strains with iron BC Leptospirillum sp. And Acidithiobacillus sp. (AGBAJA-1 and AGBAJA-2, respectively) were isolated from Agbaja Mines of Kogi State Nigeria. Bioleaching studies carried out shows that prior to inoculation of the iron ore solution with the organisms, raw Agbaja iron ore had a concentration of 25.10 mg/g iron while Zinc, Copper and Lead were 1.3903 mg/g, 0.094 mg/g, and 0.2813 mg/g respectively from X-ray diffraction analysis. The degree of bioleaching as a function of the amount of iron leached into solution was higher (in four weeks bioleaching test) than the other metals. Molecular characterization by sequencing the 16S ribosomal unit, amplification with universal primers, yielded high quality amplicons that were sequenced. Their phylogenetic/Blast comparison showed more than 97% relationships with Acidithiobacillus ferroxidans ATCC 23270 and Leptospirillum ferrovirans DSM 15468, families of bacteria in the National Centre for Biotechnology Information (NCBI) data bank. These are moderately thermophilic acidophilic bacteria that may represent an opportunity for developing a greener iron extraction process.

Studies on properties of concrete prepared with partial replacement of Coarse aggregate by Electric Arc Furnace Slag

In recent decades, the construction industry is facing a difficulty arising out of decline in the availability of natural resource material for the preparation of concrete due to depletion. An investigation is carried out on the reuse of waste slag as an alternative material to natural material in concrete production, satisfying relevant international standards. Electric Arc Furnace Slag (EAFS) is a material which is obtained from the steel industry during the production of steel from its raw ore. It can be used as both fine and coarse aggregate in concrete. This paper presents about the usage of EAFS in concrete preparation and results of some tests conducted on it. This study concentrates on 50% replacement of EAFS as coarse aggregate in concrete preparation. The mechanical properties of the EAFS is addressed. The compressive and split tensile strength is analysed for the age of 7, 14 and 28 days. The test results revealed that partial replacement of EAFS as coarse aggregate showed more or less similar results when compared to conventional concrete. Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) techniques are used to study topographic, crystallographic of material and chemical composition of slag and the corresponding results are included.

Synthesis and Characterization of Polyaluminum Ferric Chloride (PAFC) Coagulant with Superior Turbidity Removal Capacity from K-feldspar/NaOH Extraction Residues

The aim of this work was to synthesize polyaluminum ferric chloride coagulant with significant coagulation performance employing K-feldspar/NaOH leaching residue as precursor. Potassium extraction from K-feldspar through sodium hydroxide calcination method is carried out at optimum, activation temperature, time, mass ratio of NaOH to K-feldspar ore in a muffle furnace followed by deionized water conventional leaching. The extraction residues are engaged in co-polymerization of aluminum and iron for the synthesis of polyaluminum ferric chloride (PAFC). The favorable conditions, concentration of hydrochloric acid, hydrochloric acid to residue ratio (v/m), temperature, time and pH are comprehensively investigated. Main process conditions for K extraction are: ore particle mass ratio of NaOH/ore 1.5:1, calcination temperature at 500 °C, and calcination duration of 2 hours, which all jointly yielded an extraction of 95% potassium, whereas polyaluminum ferric chloride (PAFC) synthesis favorable conditions are: HCl concentration of 5M, HCl/residue 5.5:1(v/m), time 2 hours, temperature 100 ℃ and pH 7. 99.8% turbidity elimination efficacy from an initial turbidity of 125 NTU kaolin suspension is obtained. The XRD study is implemented for raw ore, slag and leach residue and proved existing all possible structural changes occurred in extraction routes, additionally FTIR and ICP-MS employed in investigation of polyaluminum ferric chloride (PAFC) to reveal the functional group configuration within the elements of a coagulant and component analysis respectively.

Structural Economic Assessment of Polymetallic Nodules Mining Project with Updates to Present Market Conditions

This paper presents the economic structure, assumptions, and relations of deep-sea mining project assessment and the results of its evaluation, based on exploration activities and research in the field of geology, mining technology, processing technology, and environmental and legislative studies. The Interoceanmetal Joint Organization (IOM) and cooperating organizations conducted a study incorporating those elements of the project that are recognized as most important for commercial viability. On the basis of formulated financial flow of operating and capital expenses of one processing technology the possible market unit price of polymetallic nodules was estimated and the result is presented in this paper. The rapidly changing economic situation, affected inter alia by the COVID-19 pandemic, is reflected in the study and updated results are based on recent changes in metal prices. Although assumptions related to mining costs need to be confirmed during pilot mining tests, promising results have been shown in the case of the use of high-pressure acid leaching processing technology (HPAL) as well as in the case of raw ore sales. A pre-feasibility study of the project will focus on the two most promising variants of the model.

Low-carbon production of iron and steel: Technology options, economic assessment, and policy

Summary Given increased urgency to transition the global economy to net-zero CO2 emission, governments and industry have increased focus on decarbonizing hard-to-abate sectors, including steel making, which contributes roughly 6% of global CO2 emission and 8% of energy-related emission (including power consumption emission). This paper reviews current global iron and steel production and assesses available decarbonization technologies, including hydrogen injection, solid biomass substitution, zero-C electricity substitution, carbon capture and storage (CCS) retrofit, and combinations of these decarbonization approaches. Blast furnace-basic oxygen furnace (BF-BOF) dominates production (71%) and is particularly stubborn to any decarbonization technology. Direct reduced iron to electric arc furnace (DRI-EAF) production is 5% and growing, it appears to have better decarbonization potential to move toward net-zero. Secondary steel production using mainly steel scrap in electric arc furnace (EAF-scrap) is 24% of global production and has both the lowest energy consumption and is technically simplest to decarbonize through electrification but is limited in market share to recycled steel capacity. Of the options assessed, blue hydrogen, carbon neutral biomass, and CCS appear to have the lowest cost and highest technical maturity. However, no single approach today can deliver deep decarbonization to the iron and steel industry and all approaches lead to substantial production cost increase. No uniform ideal solution exists, and different geographies, infrastructure, and economies will determine the local optimum solution with viability and cost. Policy measures will be required to provide financial incentives for decarbonization and to avoid unwelcome outcomes such as emissions leakage or job loss.

Recycling iron from oolitic hematite via microwave fluidization roasting and magnetic separation

Oolitic hematite is an iron ore resource with complex refractory characteristics, abundant reserves, and significant recycling value. In this study, a clean and innovative microwave fluidization roasting method was developed. Iron concentrate with an iron grade of 58.72% and iron recovery of 89.32% was obtained via microwave pretreatment at 1050 °C for 2 min, followed by magnetization roasting at 650 °C for 5 min at a CO content of 30% and total gas volume of 700 mL/min. A vibrating-sample magnetometer analysis indicated that the saturation magnetization increased from 0.33 A·m2/kg for the raw ore to 42.52 A·m2/kg for the roasted products. Scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed that microwave pretreatment promoted the formation of microcracks at the interfaces between minerals, offering the advantages of a rapid reaction and phase transformation during the magnetization roasting. X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy analyses indicated that the iron mineral phase was selectively transformed from weakly magnetic hematite into strongly magnetic magnetite and that the iron mineral was effectively recycled from the roasted samples via magnetic separation.

Selective flotation of galena using a novel collector S-benzyl-N-ethoxycarbonyl thiocarbamate: An experimental and theoretical investigation

A novel collector S-benzyl-N-ethoxycarbonyl thiocarbamate (BET) was used for selectively recovering galena from a polymetallic sulfide ore, and its flotation performance, structure-property relation and adsorption mechanism to galena were investigated. The raw ore flotation experiment demonstrated that compared with two conventional collectors sodium diethyl dithiocarbamate (SDD) and ammonium dibutyl dithiophosphate (ADD), BET displayed superior flotation performance to galena. Pure mineral flotation and adsorption tests also illustrated that among the three collectors BET possessed the strongest collecting ability and the best selectivity toward galena. The structure-property relation study based on density functional theory (DFT) calculation supported the above conclusion. The adsorption mechanism analysis through DFT calculation indicated that BET was chemisorbed on galena surface via formation of normal covalent bond between carbonyl S atom and Pb atom and back donation covalent bond between carbonyl O atom and Pb atom, which was verified by the result of Fourier Transform Infrared (FTIR) spectra analysis. This new collector exhibits not only strong collecting ability but also good selectivity to galena, and therefore it has wide industrial application prospect.

New depression mechanism of polymeric depressant on titanaugite in ilmenite flotation

In this paper a polymer reagent, sodium polystyrene sulfonate (PSSNa), was introduced as the effective depressant of titanaugite in ilmenite ore flotation, in contrast to that most of the organic sulfonate were usually used as the collector. And the selective adsorption and depression mechanisms of PSSNa were investigated through diverse methods. The results of the exploratory trial on raw ilmenite ore flotation show that polymeric PSSNa is qualified for the depressant of titanaugite in ilmenite ore flotation, and has better depression performance relative to the traditional SS depressant. From the results of artificial ilmenite ore micro-flotation, PSSNa exhibited almost no effect on the ilmenite flotation but depressed strongly the titanaugite mineral, may being due to its selective adsorption onto ilmenite and titanaugite surface. This was determined by the consequences of surface micro-polarity detection. PSSNa on titanaugite cause the increase in surface polarity, thus the enhancement in hydrophilicity, and further the depression of its flotation. FTIR results illustrate that the adsorption of PSSNa on both minerals surface are mainly the chemisorption, and on ilmenite it is a weak adsorption while it is a stronger adsorption on titanaugite surface, which is the origin of its selectivity in ilmenite ore flotation.

ENRICHMENT OF APATITE-BEARING IRON ORE BY MAGNETIC SEPARATION AND FLOTATION

In this study, enrichment possibility of apatite-bearing iron ore sample was investigated to obtain iron and phosphate concentrates, separately. It was determined that the raw iron ore contains 35.75% Fe and 5.36 P2O5. Magnetite from the ore can be enriched with low field strength wet magnetic separators, and apatite can be enriched from magnetite residues by flotation. For this purpose, the raw ore was ground to minus 106 m size and then subjected to magnetic separation and following flotation. According to experimental result, a magnetite concentrate containing 63.55% Fe and 0.65% P205, and a phosphate concentrates containing 25.33% P2O5 and 6.45%Fe were obtained. The results show that there are still difficulties in obtaining low iron-containing apatite concentrate. It is concluded that it is difficult to separate the iron and phosphorus minerals from each other, probably due to complex mineralogical composition and poor mineral liberation of the ore.

Effect of scrubbing medium’s particle size on scrubbing flotation performance and mineralogical characteristics of microcrystalline graphite

Scrubbing is a suitable method for cleaning fine slime on the surface of microcrystalline graphite, improving its flotation performance. However, little attention has been paid to the effect of the scrubbing medium’s particle size on enrichment efficiency of scrubbing flotation of microcrystalline graphite. In this work, scrubbing parameters (i.e., scrubbing medium’s particle size, stirring speed, and solid concentration) were optimized via response surface methodology using Box-Behnken design to yield the maximum enrichment efficiency of graphite ore. The scrubbing medium’s particle size was found to be the most important influencing factor. The optimal conditions for scrubbing process were obtained and tested to confirm the results predicted by the Design-Expert software. The enrichment efficiency of graphite treated with scrubbing media of different sizes was compared under optimal stirring speed and solid concentration conditions. The effect of the scrubbing medium’s particle size on the scrubbing flotation of graphite was investigated by a comparison of the graphite particle size distribution before and after scrubbing, and field emission scanning electron microscopic examination of raw ore and flotation concentrates.

Effects of High Proportion Unground Sea Sand Ore on the Preparation Process and Reduction Performance of Oxidized Pellets

The New Zealand sea sand ore is a kind of vanadia–titania magnetite formed by erosion in the coastal zone. Because of its coarse particle size, smooth spherical particles, complex chemical composition, it has been added to sinter as an auxiliary material. Based on the principle of optimizing ore blending to strengthen advantages and weaken disadvantages, this paper used New Zealand sea sand raw ore that has not undergone any pretreatment as the main material and prepared it into oxidized pellets using a disc pelletizer and explored the influence of high-proportion unground sea sand ore on the preparation process and reduction performance of oxidized pellets. The influence of unground sea sand ore on the falling strength, compressive strength, reduction swelling index, and reduction degree of pellets was analyzed by the ICPAES, XRF, XRD, SEM-EDS, and other detection methods, and the change laws and influencing factors of oxidized pellets were analyzed. With the increase of the amount of unground sea sand ore used, the falling strength and compressive strength of the green pellets first decreased and then gradually increased, while the compressive strength of the oxidized pellets first increased and then decreased. At the same time, as the amount of sea sand ore used increased, the reduction process of pellets was restricted. The reduction swelling index and the reduction degree index generally show a downward trend. However, the compressive strength of the pellets gradually increased after reduction. Through the research on the pellet-forming performance and reduction properties of unground sea sand ore, it is shown that when the amount of unground sea sand ore used was 40%, it can still be used as raw material for blast furnace ironmaking. Thus, this research provided specific data support for iron and steel enterprises to improve the ratio of unground sea sand ore and reduce production cost.

Sustainable Underground Iron Ore Mining in Ukraine with Backfilling Worked-Out Area

The present paper considers aspects of underground iron ore mining in Ukraine, in particular the level of mine production and reserves of basic ore fields. It analyzes and generalizes the practice of using cemented rockfill under difficult mining and hydrogeological conditions of the Pivdenno-Bilozerske high-grade iron ore field. The Belozersky iron ore district is the only one in Ukraine that, without any technological cycle of beneficiation, can provide both domestic and foreign consumers with high-quality raw iron ore as required by world markets. The PJSC Zaporizhzhia iron ore plant extracts iron ore from the Pivdenno-Bilozerske field with an iron content of more than 60% using the low-waste, environmentally friendly technology of backfilling the mined-out area with a hardening mixture. The peculiarities of the technology for steep deposit mining and the main processes of backfilling operations in terms of preparation, transportation, and construction of the backfill mass with its stability assessment are explained in detail in this paper. As a result of using cemented rockfill, rock mass stability is provided, a considerable part of industrial waste is disposed of in the mined-out area, and the earth’s surface subsidence within the area is prevented (in comparison with mining enterprises in other fields).

Study on microwave-assisted grinding and liberation characteristics for Ludwigite

To effectively separate the valuable minerals in ludwigite, this study investigated the grinding fineness behaviour and liberation characteristics. The results indicated that the particle yield of −75 μm with a microwave power of 4 kW for 40 s was increased by 18.22% in comparison to that of raw ore. The D(50) and D(90) raw-ore grinding products reached 53.52 and 215.16 μm, both of which were larger than microwave-treated samples. The particle-size distribution of the grinding products for treated ore was more uniform, and the amount of coarse and over-ground particles decreased significantly. The specific surface area, pore volume and pore diameter of the large particles were effectively increased after microwave heating, which improved the crushing and grinding characteristics of the grinding products by lowering the relevant mechanical properties. The monomer liberations of magnetite, ascharite and serpentine of microwave-treated ore samples were 55.33%, 35.48% and 74.98%, respectively, which represented an increase of 12.06%, 9.37% and 6.22% in comparison to untreated ore samples. The bonding characteristics among different minerals were altered through microwave treatment to weaken the bonding force and reduce the proportion of interlocked minerals, which allows these complex minerals to easily liberate after secondary grinding.

Study on Technological Process Innovation of Non-Cyanide Leaching

Nowadays, there are many gold leaching processes, and the dominant one is cyanidation, but the virulence of cyanidation seriously endangers the environment and human health. In order to reduce environmental pollution and improve the recovery rate of gold, metallurgical workers put forward a variety of new gold leaching methods, which can be roughly divided into two types: one is to develop pretreatment technology on the basis of traditional cyanidation method; The other is non-cyanide leaching of gold. Based on the existing Non-Cyanide leaching technology, this paper puts forward the process innovation of Non-Cyanide leaching technology, thiourea method and dilute nitric acid pre-oxidation treatment process. The thiourea non-cyanide leaching system was investigated. According to the leaching situation of gold and silver in raw ore, the innovative scheme of gold and silver leaching technology was selected. Compared with other treatment methods, thiourea method and dilute nitric acid pre-oxidation treatment technology overcome the danger of high pressure, and the nitrogen oxide gas produced in the dilute nitric acid oxidation process can be recycled, which basically does not pollute the environment.

The practice of geological mapping of the Zhdanov deposit ores in the Kola peninsula

Geological mapping is included in each stage of geological prospecting. How detailed and consistent the obtained data are directly depends on how thoroughly an object has been studied. The main purpose of geological mapping is to identify areas with uniform ore and to give recovery projections. Gipronikel Institute has been engaged in such work for 30 years and has accumulated a great number of successful practices. As an example, this paper describes the results of geological mapping that was done for the Zhdanov deposit of copper-nickel sulphide ores in the Kola Peninsula. This study resulted in identifying geological types of ores (such as raw, refractory and talcose ores), which can be processed following the same process sequence but with different performance. The key differentiation criteria included the concentration of valuable components, the share of coarsely disseminated sulphides in the total amount of sulphides contained in a sample, the concentration of the easily floatable mineral — i.e. talc. Due to high variability in the material composition of striking and dipping ore bodies, the deposit has seen geological mapping conducted continuously for more than 10 years. Over that period, a database was created showing the distribution of different geological types of ore and the variability in the estimated recovery of nickel and copper, which is used for concentrator plant operations planning based on prospecting data.

A circular economic approach to the phytoextraction of Zn from basic oxygen steelmaking filtercake using Lemna minor and CO2

Two billion tonnes of alkaline metallurgical waste is generated per year as a product of industry, mining, and metal processing. Filtercake is one such residue formed as a bi-product of steelmaking. Metal rich bi-products can be both an environmental concern and potential resource. High concentrations of heavy metals, if accessed, could be utilised and reprocessed reducing both pollution and the demand for raw metal ores. Phytoextraction is one such method of recovering metals from contaminated mediums. Research interest in Lemna sp. has grown due to their phytoremediation potential. Facilitated by rapid growth and accumulation of nutrients and metals, Lemna minor has been described as one of the most effective macrophytes for remediating contaminated water. The present study outlines a system using L. minor to extract Zn from filtercake when submerged in static water. To facilitate phytoremediation, CO2 carbonation can be employed to solubilise elements and utilise this greenhouse gas, another a bi-product of steel industry. The addition of CO2 to vessels of water containing filtercake lowered the pH from as high as 8.8 to 5.6 and significantly increased Zn in solution compared to vessels receiving no CO2. Results suggest the potential of L. minor to accumulating 68.7 kg Zn per year from 20.5 Mt. filtercake ha−1. This system facilitates a circular economy with re-use of multiple existing bi-products. In addition, the potential employment of biomass in biofuel production and use of remediated filtercake in carbon sequestration adds further environmental and socio-economic impact. The extent to which the approach was consistent with circular economy was discussed and its wider integration considered.

Effect of calcination temperature on rare earth tailing catalysts for catalytic methane combustion

AbstractBayan Obo tailings are rich in rare earth elements (REEs), iron, and other catalytic active substances. In this study, mine tailings were calcined at different temperatures and tested for the catalytic combustion of low-concentration methane. Upon calcination at 600°C, high catalytic activity was revealed, with 50% CH4 conversion at 587°C (space velocity of 12,000 mL/g h). The physicochemical properties of catalysts were characterized using thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, hydrogen temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). Compared to the raw ore sample, the diffraction peak intensity of Fe2O3 increased post calcination, whereas that of CeCO3F decreased. A porous structure appeared after the catalyst was calcined at 600°C. Additionally, Fe, Ce, Ti, and other metal elements were more highly dispersed on the catalyst surface. H2-TPR results revealed a broadening of the reduction temperature range for the catalyst calcined at 600°C and an increase in the reduction peak. XPS analysis indicated the presence of Ce in the form of Ce3+ and Ce4+ oxidation states and the coexistence of Fe in the form of Fe2+ and Fe3+. Moreover, XPS revealed a higher surface Oads/Olatt ratio. This study provides evidence for the green reuse of Bayan Obo mine tailings in secondary resources.

Effect of separating tank of compound dry separation bed on oil shale separation performance

Oil shale is an unconventional oil and gas resource, and because of its high utilization value, it has been listed as an important alternative energy source of the 21st century. In this study, through the analysis of raw ore, design and development of a composite dry sorting machine was proposed to sort the original ore, and the distribution rule of oil shale particles in separation tank was analyzed. The effects of trough height, amplitude, and frequency on layered separation of oil shale in trough were also systematically investigated. The results showed that under the best operating parameters (height = 55–60 mm, amplitude = 3.2–3.6 mm, and frequency = 36–39 Hz), the groove on the surface of the composite dry separation bed exhibited good sorting effect. The particles were clearly layered on the bed surface according to density. The oil content of the original ore was 4.39% and that of the obtained concentrate was 10.05%, and the yield was 40.57%. Moreover, the oil content of the tailings was 0.51%, and the yield was 59.43%. The composite dry separator shows a good separation effect on the recycling of oil shale.

Laboratory Testing of Scheelite Flotation from Raw Ore in Sangdong Mine for Process Development

Tungsten is an essential metal for the manufacture of special alloys, which is in constant demand due to the development of the industry. The recovery of scheelite from undeveloped tungsten ore in South Korea was investigated to improve the flotation performance for high grade and recovery of concentrate. To investigate the interaction between the flotation reagents and the minerals, the adsorption experiments of oleic acid as a collector on Ca-bearing minerals, such as scheelite, calcite, and fluorite were carried out. This reaction was confirmed chemical adsorption by analysis of zeta potential and FTIR analysis. The batch test was performed using a raw ore to enhance the grade and recovery of the scheelite concentrate. It was obtained at the optimal conditions for high WO3 grade and recovery of scheelite concentrate by using a simple process. In particular, the sodium carbonate used as a pH modifier was investigated to increase scheelite flotation performance by supporting the selective depression of Ca-bearing gangue minerals. Furthermore, a locked cycle test (LCT) was carried out based on batch test results for the design of a continuous pilot plant.