Ore Blending Research Articles

Mineralogical Prediction on the Flotation Behavior of Copper and Molybdenum Minerals from Blended Cu–Mo Ores in Seawater

The copper ore in Chilean copper porphyry deposits is often associated with molybdenum minerals. This copper–molybdenum (Cu–Mo) sulfide ore is generally mined from various locations in the mining site; thus, the mineral composition, oxidation degree, mineral particle size, and grade vary. Therefore, in the mining operation, it is common to blend the ores mined from various spots and then process them using flotation. In this study, the floatability of five types of Cu–Mo ores and the blending of these ores in seawater was investigated. The oxidation degree of these Cu–Mo ores was evaluated, and the correlation between flotation recovery and oxidation degree is presented. Furthermore, the flotation kinetics of each Cu–Mo ore were calculated based on a mineralogical analysis using mineral liberation analysis (MLA). A mineralogical prediction model was proposed to estimate the flotation behavior of blended Cu–Mo ore as a function of the flotation behavior of each Cu–Mo ore. The flotation results show that the recovery of copper and molybdenum decreased with the increasing copper oxidization degree. In addition, the recovery of blended ore can be predicted via the flotation rate equation, using the maximum recovery (Rmax) and flotation rate coefficient (k) determined from the flotation rate analysis of each ore before blending. It was found that Rmax and k of the respective minerals slightly decreased with increasing the degree of copper oxidation. Moreover, Rmax varied greatly depending on the mineral species. The total copper and molybdenum recovery were strongly affected by the degree of copper oxidation as the mineral fraction in the ore varied greatly depending upon the degree of oxidation.

A framework for near real-time ROM stockpile modelling to improve blending efficiency

PurposeIn the mining industry, a run-of-mine (ROM) stockpile is a temporary storage unit, but it is also widely accepted as an effective method to reduce the short-term variations of ore grade. However, tracing ore grade at ROM stockpiles accurately using most current fleet management systems is challenging, due to insufficient information available in real time. This study aims to build a three-dimensional (3D) model for ROM stockpiles continuously based on fine-grained grade information through integrating data from a number of ore grade tracking sources.Design/methodology/approachFollowing a literature review, a framework for a new stockpile management system is proposed. In this system, near real-time high-resolution 3D ROM stockpile models are created based on dump/load locations measured from global positioning system sensors. Each stockpile model contains a group of layers which are separated by different qualities.FindingsAcquiring the geometric shapes of all the layers in a stockpile and cuts made by front wheel loaders provides a better understanding about the quality and quality distribution within a stockpile when it is stacked/reclaimed. Such a ROM stockpile model can provide information on predicating ore blend quality with high accuracy and high efficiency. Furthermore, a 3D stockyard model created based on such ROM stockpile models can help organisations optimise material flow and reduce the cost.Research limitations/implicationsThe modelling algorithm is evaluated using a laboratory scaled stockpile at this stage. The authors expect to scan a real stockpile and create a reference model from it. Meanwhile, the geometric model cannot represent slump or collapse during reclaiming faithfully. Therefore, the model is expected to be reconcile monthly using laser scanning data.Practical implicationsThe proposed model is currently translated to the operations at OZ Minerals. The use of such model will reduce the handling costs and improve the efficiency of existing grade management systems in the mining industry.Originality/valueThis study provides a solution to build a near real-time high-resolution multi-layered 3D stockpile model through using currently available information and resources. Such novel and low-cost stockpile model will improve the production rates with good output product quality control.

Effect of Bonding Area Formation During Sintering on the Reaction Characteristics of Iron Ores

This study aims to understand the effect of sintering at 1623 K on the reaction characteristics of iron ores. By investigating the reaction characteristics of nine different iron ores with disparate properties, new reactivity indices including the iron ore reactivity index (IRI) and iron ore blending reactivity index (IBRI) independent of the sample size are derived based on the melt penetration depth of preformed cubicalironore tablets. Furthermore, the effect of sintering on the reactivity of iron ore is also identified. Using a rapid heating/cooling infrared furnace equipment, duplicate iron ore reaction tests are conducted to increase the reproducibility of the results. The case of a high IBRI in the sintering process increases the product yield and average particle size of the sinter. When the IBRI increases by 0.1, the product yield increases by 0.4% and the average size of the sintered ore increases by 0.1 mm. The results show that the degree of reaction between iron ore and additives can be estimated during the iron ore blending step and be easily applied in managing commercial‐scale sinter production and quality.

A Method of Ore Blending Based on the Quality of Beneficiation and Its Application in a Concentrator

Ore blending is an essential part of daily work in the concentrator. Qualified ore dressing products can make the ore dressing more smoothly. The existing ore blending modeling usually only considers the quality of ore blending products and ignores the effect of ore blending on ore dressing. This research proposes an ore blending modeling method based on the quality of the beneficiation concentrate. The relationship between the properties of ore blending products and the total concentrate recovery is fitted by the ABC-BP neural network algorithm, taken as the optimization goal to guarantee the quality of ore dressing products at the source. The ore blending system was developed and operated stably on the production site. The industrial test and actual production results have proved the effectiveness and reliability of this method.

Visible-NIR spectral characterization and grade inversion modelling study of the Derni copper deposit

At present, chemical analysis is the main method for copper ore grade verification. Because of its long test cycle and lag effect relative to mining and ore blending processes, this approach cannot effectively reduce losses in mineral resource mining. An effective way to solve this problem is to conduct research on in situ grade determination methods for ore bodies based on visible-near-infrared hyperspectral grade modelling techniques. However, the accuracy of the modelling is seriously reduced by the large redundancy of hyperspectral data and the self-limiting nature of some machine learning methods. Therefore, the accurate selection of dimensionality reduction algorithms and machine learning algorithms determines the accuracy of the inverse model, and the setting of parameters such as dimensionality reduction, number of nearest neighbour points and number of hidden layers in neural networks is crucial. In this paper, 190 ore samples were collected from the open pit of the Derni copper deposit in Dawu town, Guoluo Tibetan Autonomous Prefecture, Qinghai Province, China. First, the visible-near-infrared spectral data for the sample set were obtained with an SVC HR-1024 spectrometer. The copper grade of the sample set was verified by chemical analysis. Three algorithms—the Laplacian eigenmap (LE), local tangent space alignment (LTSA) and local linear embedding (LLE)—were used to reduce the dimensionality of the original hyperspectral data. The original data and the three hyperspectral datasets after dimensionality reduction were used as data sources. Several Derni copper grade inversion models based on two machine learning algorithms, the backpropagation neural network and radial basis function (RBF) neural network, were developed. Finally, the coefficient of determination (R2), mean absolute error (MAE) and root mean square error (RMSE) were used to evaluate the accuracy of each model. The results show that the accuracy of the model built with spectral data processed by the dimension reduction algorithm is higher than that of the model constructed with the original spectral data. Among the above combined models, the LLE-RBF model has the highest inversion accuracy. The MAE of the model is 0.117%, the RMSE is 0.136, and R2 is 0.934.

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.

ВАРІАТИВНІСТЬ ФІЗИЧНИХ І ХІМІЧНИХ ВЛАСТИВОСТЕЙ МАГНЕТИТУ ТА КВАРЦУ ПІВНІЧНОГО РАЙОНУ КРИВОРІЗЬКОГО БАСЕЙНУ

Physical properties of minerals represent a function of their chemical composition, features of morphology and anatomy. Their variability is influenced by geological syngenetic and epigenetic processes that occur within the iron ore deposits of Kryvyi Rih basin. The latter is represented by nine deposits, which are exploited by five ore mining and enrichment works (GZKs). The Northern region of Kryvyi Rih basin includes Hannivske and Pervomayske deposits. The productive strata of both deposits consist of low-grade magnetite ores of the fifth and sixth ferruginous horizons. They are characterized by the authigenic-metamorphogenic mineralogical zonation. The purpose of the work is conditioned by the need for a detailed study of the laws of variability of chemical composition and physical properties of rock-forming minerals (magnetite and quartz), taking into account their position within zonal ore deposits. The study of the physical properties of rock-forming minerals was carried out according to standard methods using a microhardness tester, the chemical composition was investigated by segregating monomineral fractions of magnetite and quartz from ores of metamorphic or metasomatic origins of various mineral composition using a magnetic separator. The chemical analyzes were carried out in a standardized chemical laboratory. Statistical studies were performed using Excel software and Corel Draw. Result of the researches showed the nature of variability of the chemical composition, physical properties of magnetite and quartz in the sections of metamorphogenic and metasomatically altered ore strata of iron ore deposits. Practical significance is conditioned by the necessity of conducting detailed topomineralogical study of the productive strata of iron ore deposits of Kryvyi Rih basin in relation to the work on updating the mineralogical and technological map of the deposit, compiling an optimal scheme for ore blending in order to increase efficiency of the use of natural technological potential of magnetite quartzites on the basis of studying physical and chemical properties of the main rock-forming minerals of ferruginous quartzite.

Hyperspectral Characteristics of Oil Sand, Part 1: Prediction of Processability and Froth Quality from Measurements of Ore

This study is the first of two companion papers using hyperspectral data to generate predictive models of oil sand ore and froth characteristics as a potential new means for process control. In Alberta, Canada, shallow oil sands deposits are accessed by surface mining and crushed ore is transported to a processing plant for extraction of bitumen using flotation processes. The ore displays considerable variability in clay, bitumen, and fines which affects their behavior in flotation units. Using oil sand ore spanning a range of bitumen and fines characteristics, flotation experiments were performed to generate froth in a batch extractor to determine ore processability (e.g., separation performance) and froth characteristics (color, bitumen, solids). From hyperspectral observations of ore, models can predict the %bitumen content and %fines (particle passing at 44 and 3.9 µm) of ore but the models with highest r2 (>0.96) predict the solids/bitumen of froth and the processability of ore. Spectral observations collected on ore upstream of the separation vessels could therefore offer a first order assessment of froth quality for an ore blend before the ore enters the plant. These models could also potentially be used to monitor and control the performance of the blending process as another means to control the performance of the flotation process.

Sintering Characteristics of Iron Ore Blends Containing High Proportions of Goethitic Ores

Two ore blends containing substantial channel iron deposit (CID) and Marra Mamba (MM) ores were assessed. The blends granulated well with addition of hydrated lime, which was found to improve the morphology and strength, and consequently the bed permeability of the resultant green granules. Compared with Blend 2 (a simulated industry blend), Blend 1, containing more MM and less CID ores was slightly less permeable but required similar moisture to achieve its optimum permeability. Both blends showed similar sintering characteristics as evidenced by sintering productivity and sinter quality, suggesting that Blend 1 was comparable to Blend 2. This was further supported by observations of sinter macro- and microstructure. Addition of hydrated lime improves the bed permeability and the formation and fluidity of sinter melt, consequently leading to improved sinter yield and strength along with sintering productivity. To achieve sinter return balance, the sinter return ratio had to decrease as the coke addition increased.

Phase Development in the Sintering of a Hematite–Ilmenite Ore Blend

The use of low-grade iron ores has attracted a lot of interest where fines from these ores are sintered to improve their strength. Ti-containing ores are one of the abundantly available iron ores of low-grade. The sintering of the hematite–ilmenite ore blends has several challenges, which include the formation of perovskite. The sintering behavior of a hematite–ilmenite ore sinter blend was investigated in 75 vol% N2, 24 vol% CO2, and 1 vol% CO in the temperature range of 1373 to 1523 K. Phase development and distribution of metallic elements were investigated by x-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and electron probe microanalysis (EPMA). The addition of ilmenite ore to hematite ore increased the temperature of melt formation. More titanium (Ti) was distributed in the glass phase with increasing temperature. Morphological change showed that the amount of sinter-bonding phase generated was low, below 1473 K. Weak sinter bonding strength might be caused by the presence of Ti in the glass phase at high temperature. This might affect the fracture toughness of the glass phase.

A Process Mineralogical Evaluation of Chromite at the Nkomati Nickel Mine, Uitkomst Complex, South Africa

A process mineralogical study based on three texturally and mineralogically different chromite-bearing ore types at the Nkomati nickel mine was undertaken, with focus on chromite. Chromite is a by-product of the Ni-Cu-Co-PGE ore at Nkomati Nickel mine. These being the PCMZ_MG (medium-grade Ni-Cu sulphide silicate ore with disseminated chromite), PCMZ_HG (high-grade Ni-Cu sulphide silicate ore containing disseminated chromite) and MCHR (massive chromite unit) ore types. These were processed using benchtop flotation followed by gravity concentration using a shaking table at different grind sizes. Quantitative mineralogical data was obtained using a 600F Mineral Liberation Analyser for the unprocessed and processed ores at three selected target grinds. The Mineral Liberation Analyser data indicated that increased milling does not relate to increased chromite grades and recoveries, particularly for the disseminated PCMZ type ores based on laboratory-scale gravity concentration. The recovery is controlled largely by the chromite chemistry. The results also showed that the MCHR samples that underwent a pre-flotation stage before gravity separation had better Cr2O3 grades (45% to 47%) and recoveries (52% to 61%) than MCHR ore that did not undergo a pre-flotation stage, which recorded grades ranging from 44% to 46% and recoveries ranging from 43% to 60%. This holds promise for the blending of MCHR ores with the PCMZ ores. The PCMZ ores also displayed better Cr2O3 grades and recoveries at coarser grinds. The optimal target grind to process all three ore types is a P80 of 75 μm, which is the current grind size employed at Nkomati Nickel mine. Due to the low nickel price and grade the Nkomati Nickel mine is currently under care and maintenance.

Improving the Softening and Melting Properties of Ferrous Burden with High Al<sub>2</sub>O<sub>3</sub> Content for Blast Furnace by Ore Blending

Improving the Softening and Melting Properties of Ferrous Burden with High Al<sub>2</sub>O<sub>3</sub> Content for Blast Furnace by Ore Blending

Sintering Properties of Magnetic Separation Nonferrous Metallurgical Tailings

In this paper, the tailings produced by non-ferrous metallurgy were magnetically separated to obtain magnetic separation tailings. The sintering performance of magnetic separation tailings was studied by sintering cup experiment platform. In the research process, the differences in sintering process of different magnetic separation tailings were compared, including vertical sintering speed, sintering coefficient, drum strength, finished product rate, end point temperature and other sintering indexes. At the same time, the obtained sinter was subjected to chemical analysis to obtain its specific components. The influence of magnetic separation tailings with different contents on sintering was obtained by ore blending. The experimental results showed that the copper tailings are not sintered and the yield is only 0%. Tin tailings are not sintered and the yield is only 22.30%. The aluminum tailings can be sintered into lumps with a yield of only 57.10%. As the proportion of magnetic separation tailings increases, the vertical sintering speed decreases, the sintering utilization coefficient decreases, the sinter drum index decreases, the yield decreases, the sinter grade decreases, and the SiO2, S and P contents increase. In actual production, the proportion of magnetic separation tailings should be controlled below 10%.

Studies on Beneficiation of Manganese Ore through High Intensity Magnetic Separator

Upgradation techniques like wet sieving and magnetic separation were used to evaluate the beneficiation potential of manganese ore. During wet sieving, manganese content in raw ore was upgraded from 27% to a maximum value of 38% in the concentrate with a recovery of 30%. Size classification was found to have no measurable effect on manganese grade in magnetic separation. In the unsieved ground ore, manganese content of 45% was achieved with a recovery of 23% and Mn/Fe ratio of 19% at a magnetic intensity of 8500 Gauss. At the same operating conditions, SiO2 was reduced from 56% in the raw ore to 30% in the magnetic fraction. So, wet sieving technique leads to a comparatively lower manganese grade but better recovery. Conversely, a magnetic separation technique produced higher manganese grade but relatively lower recovery. Blending of the upgraded manganese ore with high grade iron ore can be done to achieve the required Mn/Fe ratio.

Effects of Furnace Slope and Rotational Speed on the Carbothermic Reduction of Celestite in a Laboratory-Scale Rotary Kiln Furnace

The carbothermic reduction of celestite is the first step in producing many strontium products. The way materials move in the rotary kiln has an essential effect on the carbothermic reduction efficiency as well as the temperature. In this study, the reduction of celestite ore and excess carbon blend in a laboratory-scale rotary kiln was investigated. In the experiments carried out at three different temperatures, the rotational speed and slope of the furnace tube were altered, and their effects on the reaction efficiency were examined. The leachability of the reduced powders and the content of the unburned coke indicated the optimal parameters for the reaction. When the speed was increased to 10 rpm, the powders were more mobile in the stack and could react more easily with the furnace atmosphere. According to the results, celestite can be reduced by carbon at temperatures of 1000–1200 °C, at rates of between 5% and 75%. The maximum reaction yield (75%) was obtained with a slope of 2° and a rotational speed of 6 rpm at 1100 °C.

Just‐in‐time learning for the prediction of oil sands ore characteristics using GPS data in mining applications

AbstractFor the mining based oilsands industry, it is desirable to determine the quality of the ore delivered to the extraction processes in real‐time to make optimal operational decisions such as optimal ore blending to achieve maximal bitumen recovery. Currently, the industry determines the real‐time ore characteristics for any given shovel Global Positioning System (GPS) location by first determining the shovel elevation from the topological mine map and then using the determined geological coordinates in the 3D geological block model. It should be noted that the block model is built based on the widely spaced core hole samples, and it is updated only on a yearly basis due to high cost of narrower core hole sampling. Thus, the block model predictions are often inaccurate in between the core hole spacing. On the other hand, mining operations data are available that contain accurate ore characteristics information in the already mined area. Therefore, in this work, we present a just‐in‐time based data‐driven modelling strategy that utilizes the recently available mining operations data to obtain reliable ore characteristics given the GPS data. The prediction capability of ore characteristics using the proposed modelling strategy is validated at core hole locations. Further, the prediction of ore characteristics at non‐core hole points demonstrate promising results.

An Optimization for Ore Blending Schedules Using Mathematical Programming Methods

An Optimization for Ore Blending Schedules Using Mathematical Programming Methods

Geometallurgy study of the Catalão I Nelsonite bodies aiming to increase the niobium production

Increasing the recovery of the niobium metal contained in the Nelsonite rocks presents a great challenge, considering the standards and the production targets of the China Molybdenum Company (CMOC) that produces phosphate and with tailings material, concentrate niobium minerals. At Chapadão mine, located in Goiás, a mid-west Brazil’s state, the weathering profile reaches up to 100 meters and the ore is subdivided into three basic types, from top to bottom: Oxidized (OX), Top Micaceous (TM) and Base Micaceous (BM). In this study, samples from these three main bodies of Nelsonite were collected and tested in laboratory scale to identify which weathering level is more favourable to niobium concentrate production. In the niobium concentration process, there can be metal losses that can jeopardize the recovery of the niobium crystals. To evaluate these losses microscopy analysis was performed using samples from industrial plant survery. The results from flotation batch tests showed that BM presented the higher mass recovery and production capacity. According to the mineralogical results the main niobium losses were identified in the barite concentrate from apatite circuit and in the screening stage in the Niobium Plant feed. The batch test results showed that adjusting the cut size of the Niobium Plant there is a potential niobium recovery upgraded to 90% from Ba-pyrochlore, and, adding the barite concentrate product as an additional mass in the tailings feed, it will result together in more than 1 t/day of niobium concentrate final product, reducing the losses and utilizing better the ore blend recovery potential.

Ore-blending optimization for Canadian iron concentrate during iron ore sintering based on high-temperature characteristics of fines and nuclei

Canadian iron concentrate (CIC) can elevate the ferrous grade and lower the contents of gangue components and harmful elements in the sinter. To understand high-temperature characteristics of CIC and typical iron ore, the formation of the melt was calculated mainly through FactSage 7.2, and melt fluidity (MF) test for iron ore fines and penetration characteristic test of CIC melt into iron ore nuclei were carried out via micro-sintering method. The results show that hematite, calcium ferrites, dicalcium silicate, and magnetite take part in the formation of the melt in N2. The formation temperature of the liquid for CIC is higher than that for hematite/limonite ore. The MF of CIC is lower than that of hematite/limonite ore fines. The MF of hematite/limonite ore fines is dominated by the liquid amount and melt viscosity. The penetration depth (PD) of CIC melt into limonite ore nuclei is smaller than that into hematite ore nuclei. The PD is related to the reaction ability of the nuclei with the melt. Based on above results, sinter pot tests were conducted. The result shows that in the base ore blends including two hematite ores and two limonite ores, adding CIC deteriorates the sintering indexes. Increasing the proportion of high-MF and small-PD hematite ore can significantly improve the sintering indexes. 10 mass% is a suitable proportion for adding CIC in ore blends.

Some basic properties of granules from ore blends consisting of ultrafine magnetite and hematite ores

Some basic properties of granules, including the granule size distribution, packed-bed permeability, and chemical composition of the adhering layer, were investigated in this study for four iron ore blends consisting of 5wt%, 25wt%, and 45wt% ultrafine magnetite and 25wt% ultrafine hematite concentrates. The effects of varying the sinter basicity (CaO/SiO2 mass ratio = 1.4 to 2.2) and adding ultrafine concentrates on the variation of the adhering-layer composition and granule microstructure were studied. Moreover, the effect of adhering-layer compositional changes on sintering reactions was discussed in combination with pot sintering results of ore blends. Increasing sinter basicity led to an increase in the basicities of both the adhering layer and the fine part of the sinter mix, which were higher than the overall sinter basicity. When the sinter chemistry was fixed and fine Si-bearing materials (e.g., quartz sand) were used, increasing the amount of ultrafine ores in the ore blends tended to reduce the adhering-layer basicity and increase the SiO2 content in both the adhering layer and the fine part of the sinter mix, which will induce the formation of low-strength bonding phases and the deterioration of sinter strength. The adhering-layer composition in granules can be estimated in advance from the compositions of the −1 mm fractions of the raw materials.