Process Mineralogy Study Research Articles

Influence of Mineralogy and Mineralogy Approach to Optimize Processing: A Case Study of Tin–Copper Polymetallic Ore

Tin-Copper polymetallic ore is a type of typical ore that cassiterite is closely associated with sulfide minerals. In mineral processing of tin–copper polymetallic ore, flotation is generally used to recover valuable sulfide minerals, while gravity separation is used to recover cassiterite. A mine in Yunnan, China, uses the traditional “flotation–gravity separation” process to recover copper and tin but faces several problems during processing, such as an insufficient copper grade in Cu concentrate, a much higher grade of As in S concentrate, and a grade of S in Sn concentrate that exceeds the standard. A process mineralogy study was conducted, with a focus on Cu–S mixed concentrate, S concentrate, and Sn rough concentrate. It was determined that the main cause of these problems is not the liberation or size distribution of valuable minerals but the superstructure of pyrrhotite, which represents one of the most abundant minerals in the products. Based on EMPA, SEM-EDS, and XRD data, both monoclinic pyrrhotite and hexagonal pyrrhotite occurred in all samples. The abundance of different superstructures of pyrrhotite in one sample was determined by means of particle extraction and area calculation from microscopic images, and the distribution characteristics of monoclinic pyrrhotite and hexagonal pyrrhotite in the whole process were clarified. This process mineralogy study indicates that the strong magnetic hexagonal pyrrhotite mainly affects the copper recovery during flotation, and the hexagonal pyrrhotite mainly affects the recovery of cassiterite during gravity separation. Strong magnetic monoclinic pyrrhotite and weak magnetic hexagonal pyrrhotite should be fully considered in the optimization of mineral processing, and the magnetic separation of pyrrhotite should be adopted to optimize the overall environment of copper flotation and tin gravity separation.

Process mineralogical study of U/Th occurrence states and the carrier minerals in refractory tantalum slag

Large quantities of work have been done previously on mineralogical properties and elements extraction of tantalum ores. However, the occurrence states and carrier minerals of U/Th in refractory slag still have not been studied in detail. The objective of this study was to investigate the tantalum slag, in order to determine the distribution and occurrences of uranium–thorium and their carrier minerals. Various techniques were used to detect the slag for chemical compositions, surface morphology and mineral dissociation. The result indicated that the U content was 1.09 × 103 mg/kg and Th was 4.62 × 103 mg/kg, thus the slag had great recovery prospect. Based on diversified characterizations, U was distributed in rare earth minerals as quantities of insoluble tetravalent forms (e.g., UF4, UO2) and a small amount of hexavalent (e.g., UF6, UO3, UO2F2), similarly Th was present in tetravalent state (e.g., ThF4, ThO2). According to AMICS (Automatic Mineral Characterization System) statistical calculation, the carrier minerals of U/Th were fluocerite, monazite and xenotime. The occurrences of U/Th were mainly in adsorption and isomorphism states in carriers, without monomers. There were high proportion of siderite and pyrolusite in slag, and radionuclides had closely relation to rare earth elements and metals. The carrier minerals were predominantly independent grains, some of which were intergrown to Fe-Mn minerals, the rare earth minerals were also associated and symbiotic with each other. By characterizing the U/Th distribution and the properties of carrier ores, this paper provided a theoretical basis for the process of recovering radionuclides from tantalum slag.

The effect of grinding circuit efficiency on the grade and recovery of copper and molybdenum concentrates

ABSTRACT The efficiency of grinding and flotation process in copper-molybdenum processing circuit, largely affected by performance of thickeners and hydrocyclones devices. The goal of this paper is to investigate the effect of the rate-limiting factors on the performance of these devices and consequently on grinding and separation efficiency of the molybdenum processing circuit. So, a full process mineralogical study have been carried out on outputs of thickeners and hydrocyclone of the molybdenite flotation circuit. According to the results, coarse-grained fractions (>50 μm) of the planar molybdenite will not necessarily be recovered by thickener and hydrocyclones. This is especially true for hydrocyclones when the inlet-load rate is high, i.e., the erroneous discharge of planar molybdenite particles from the overflow of hydrocyclone, as well as their floatability in the thickener overflow, can be attributed to the effect of particle shape and size. This issue harms the grade and recovery of flotation due to the increase in the amount of circulating load (regrinding) and consequently the generation of fine particles (<10 μm) in the hydrocyclone-milling circuit. On the other hand, the almost spherical particles of copper minerals, as well as the nonplanar molybdenite fine-grained particles, are easily removed from the hydrocyclone underflow or settled in thickeners. The introduction of copper mineral particles into molybdenum concentrate and vice versa has reduced the quality of the produced concentrate and undesirable flotation performance.

Process Mineralogy of the Tailings from Llallagua: Towards a Sustainable Activity

There are significant tin reserves in the dumps and tailings from Llallagua. Currently, this waste is being processed using gravity concentration or a combination of gravity concentration with a final stage of froth flotation. A process mineralogy study of the tailings and their products after processing in Llallagua was carried out to determine the failings of the processing system in order to contribute to designing an improved new processing scheme. The mineralogy of the feed tailings, concentrate, and final tailings was determined by X-ray diffraction, scanning electron microscopy, and mineral liberation analysis. The tailings were composed of quartz, tourmaline, illite, K-feldspar, plagioclase, cassiterite, rutile, zircon, and monazite. The concentrate essentially contains cassiterite (57.4 wt.%), tourmaline, quartz, hematite, rutile and rare earth minerals, mainly monazite and minor amounts of xenotime and florencite. The concentrate contained 52–60 wt.% of SnO2 and 0.9–1.3 wt.% REE. The final tailings contained 0.23–0.37 wt.% SnO2 and 0.02 wt.% of Rare Earth Elements (REE). Only 57.6 wt.% of cassiterite from the concentrate was liberated. The non-liberated cassiterite was mainly associated with quartz, tourmaline, and rutile. The average grain size of monazite was 45 µm and 57.5 wt.% of this was liberated. In other cases, it occurs in mixed particles associated with tourmaline, quartz, cassiterite, and muscovite. To improve the sustainability of this mining activity, the concentrate grade and the metal recovery must be improved. Reducing the particle size reduction of the processed tailings would increase the beneficiation process rates. In addition, the recovery of the REE present in the concentrate as a by-product should be investigated.

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.

Process Mineralogical Study of the Arsenical Zone from a Carlin-type Gold Deposit

In this study, mineralogical and microanalysis characterization, as well as diagnostic leaching and cyanidation tests, were performed to gain a better understanding of the refractory nature of the arsenical zone of a Carlin-type gold deposit and also to evaluate possible treatment routes to maximize gold recovery. The results obtained showed that only 56% of the ore’s gold content is amenable to direct cyanidation. The majority of the remaining gold was found as submicroscopic gold and in association with sulfide minerals, such as orpiment, pyrite, and sphalerite. It was also found that despite the abundance of silicate and carbonate minerals in the arsenical zone, they do not play a key role in the refractory nature of the ore, and gold can be liberated from such minerals by appropriate grinding. The analyses further revealed that orpiment dissolves readily during cyanidation, and this dissolution retards the kinetics of gold extraction. Pyrite and sphalerite were generally found to occur in fine network texture and in association with quartz. Flotation of such auriferous sulfides may be difficult due to their oxidized surface. Fine grinding (−20 μm) was found to be partially effective in improving gold extraction.

Application of LA-ICP-MS trace-element analysis for precious metal deportment: a case study of the Kevitsa mine, Finland

The Kevitsa mine, located in northern Finland, contains disseminated Ni–Cu–Fe sulphides and platinum-group minerals. Earlier studies had reported trace concentrations of platinum-group elements in several minerals using the electron microprobe. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), which has much lower limits of detection, was used in the present study to target potential carrier minerals (sulphide, sulpharsenide, and arsenide) as part of a process mineralogy study of the ore, with the data used to determine the deportment of the precious metals. Trace precious-metal data were obtained on pentlandite, pyrite, gersdorffite, maucherite, and nickeline for Rh, Pd, Os, Ir, Pt, and Au. A unique feature of the data was the new discovery that nickeline is a significant carrier of Au (up to 74.1 ppm), in addition to Rh, Pd, Os, Ir, and Pt. The unexpected concentration of gold in nickeline demonstrates the versatility of LA-ICP-MS analysis when using an appropriate calibration standard and established protocols.

Recovery of iron from copper tailings via low-temperature direct reduction and magnetic separation: process optimization and mineralogical study

Currently, the majority of copper tailings are not effectively developed. Worldwide, large amounts of copper tailings generated from copper production are continuously dumped, posing a potential environmental threat. Herein, the recovery of iron from copper tailings via low-temperature direct reduction and magnetic separation was conducted; process optimization was carried out, and the corresponding mineralogy was investigated. The reduction time, reduction temperature, reducing agent (coal), calcium chloride additive, grinding time, and magnetic field intensity were examined for process optimization. Mineralogical analyses of the sample, reduced pellets, and magnetic concentrate under various conditions were performed by X-ray diffraction, optical microscopy, and scanning electron microscopy–energy-dispersive X-ray spectrometry to elucidate the iron reduction and growth mechanisms. The results indicated that the optimum parameters of iron recovery include a reduction temperature of 1150°C, a reduction time of 120 min, a coal dosage of 25%, a calcium chloride dosage of 2.5%, a magnetic field intensity of 100 mT, and a grinding time of 1 min. Under these conditions, the iron grade in the magnetic concentrate was greater than 90%, with an iron recovery ratio greater than 95%.

Study of process mineralogy for hydrometallurgical extraction of vanadium and aluminum from bone coal

A process mineralogy study was conducted to guide the development of a process for the extraction of vanadic oxide (V2O5) and aluminum compounds from bone coal and its ash as well as the production of byproducts. Results show that to extract the targeted metals at higher recovery rates, one must find a suitable agent capable of destroying the structure of the mica and breaking down the lattices in which these metal-bearing minerals occur. For such minerals, metal extraction efficiency is usually low if the approach is simply adding an oxidant that cannot destroy the structure. In this research, a byproduct fluosilicic acid (H2SiF6 at 20 percent concentration from an operating phosphate fertilizer plant was found to be powerful and effective for the leaching of vanadium-bearing minerals such as mica. This environmentally friendly process improved the teachability of valuable constituents in the bone coal significantly, with the leaching rate of V2O5 increased to 94 percent, from 83 percent, and that of aluminum oxide (Al2O3) increased to 75 percent, from 40 percent. X-ray diffraction and chemical analyses showed that the structure of mica can be destroyed using fluosilicic acid either alone or in combination with sulfuric acid. Based on the process mineralogy study, a processingflowsheet was tested, which resulted in a final V2O5powder product with purity of 99.2 percent and an overall recovery rate of higher than 85 percent. The flowsheet consists of leaching, ion exchange and ammonium precipitation. With this process, various byproducts could also be generated, including aluminum fluoride, cryolite, aluminum sulfate, calcium sulfate, ammonium chloride, sodium chloride and cement admixtures.

Process Mineralogy of an Oolitic Hematite Ore and its Implications for Mineral Processing

Based on process mineralogical study of an oolitic hematite ore in SW China, the texture and structure of the ores, the occurrence of iron minerals and the dissemination of them are determined in detail, which provides scientific reference for forthcoming mineral processing technology. The mineralogical results show that the sizes of the grains are generally under 0.01mm, so the minerals cannot be liberated completely by traditional grinding technology. Moreover, the objective minerals are the assemblages of hematite and chlorite, whose amount is highly variable, so the magnetism also varies widely. Therefore, during the coming magnetic separation tests, the increment of the magnetic intensity should be strictly manipulated to determine the best condition for the ores.

Process Mineralogy of a Low Grade Cu-Ni-PGM Sulphide Ore and its Implications for Mineral Processing

Based on process mineralogical study of a low-grade Cu-Ni-platinum group metal(PGM) sulfide ore in SW China, the occurrence of Cu and Ni, the distribution of platinum group minerals (PGMs) and their relationships with other minerals are determined in detail, which provides scientific reference for forthcoming mineral processing and extractive metallurgy. The mineralogical results show that 18 individual PGMs containing all the 6 platinum group elements (PGEs) are investigated, and it can be concluded that the PGMs in the ores mainly occur as individual minerals. SEM images show that the PGMs are mainly disseminated in sulphides, most occur as inclusions or semi-inclusions, and part are inlayed along the other minerals to form coarse compound grains. Due to the the complex mineral composition and texture, processing the Cu-Ni-PGM ores by traditional flotation may be difficult to get a good processing performance.

Process Mineralogy of a Gold multi-metal Ore in Beiya, Yunna

Abstract Based on the chemical analysis data, Beiya Gold multi-metal Ore contains Au 2.17 g/t, Ag 59.36 g/t, Fe 38.51%, Cu 0.57%, Pb 2.00%, and Zn 0.48%. Chemical phase analysis shows that 95.72% Au exists as nature gold; 67.22% Fe exists as limonite and hematite, and only 23.65% exists as magnetite; 26.41% Cu exists as malachite and only 12.14% exists as sulfide minerals such as chalcopyrite and covellite; in the same way only 3.98% Pb exists as galena and 26.09% Zn exists as sphalerite. So the Systemic process mineralogy study is very necessary to guarantee separating these valuable elements from the ore reasonably and economically. Based on the process mineralogy research, reasonable technology flowsheet is worked out: the ore is ground to 90% under 0.074 mm, leaching Au firstly, then enriching Fe by low-intensity and high-magnetic separation. The Cu, Ag, Pb and Zn in the ore are unavailable now.

Study on Technological Mineralogy and the Experimental of Hematite in Fengyang Anhui

The paper researched on hematite’s characteristic of process mineralogy in Fengyang Anhui province. The chemical compositions of the ore were analyzed. The species, components of the hematite are determined, and the grain size and embedded characteristic of the ore are statistical. Some suggestions are proposed to improve the recovery of Fe2O3 according to the result of the process mineralogy study.

Characterization of the mode of occurrence of gold in Jokisivu pilot feed and products

The best processing methods for recovering gold are determined essentially by the mineralogy and particle size distribution of the gold. Therefore detailed and quantitative mineralogical work is essential for process optimization. This paper describes the process mineralogical study carried out for pilot testwork feed and products of Jokisivu gold ore. The occurrence of coarse and liberated gold particles favors gravity separation, the ensuing bulk sulfide flotation recovering the remaining sulfides. The gold lost in the tailings occurs mainly as fine-grained inclusions in silicates and also rarely as coarse grains that by-passed the gravity circuit and did not float.