Insights into gangue reagent interactions using process mineralogy

Process mineralogy is an important field within the mining industry. It is widely known that the application of process mineralogy can be used to solve problems and challenges, and as a tool for optimization, in the mineral processing plant. The field also contributes to an increased value of ore concentrates produced. However, how can the knowledge from, and experience with process mineralogy be applied to unconventional mineral deposits? The term “unconventional mineral deposits” is used for non-metallic industrial mineral deposits, construction materials, and the different types of deep sea mineral deposits.Case studies are provided from quartz and quartzites used for silicon production, the production of calcite marble as filler in paper, and deep sea mineral deposits. Emphasis is on important parameters for mineral deposits, where the ore grades are at different scales than for many metallic ores, or where the ore grade is not even relevant, but other mineralogical properties are crucial for the performance.

Modern practice of laboratory flotation testing for flowsheet development – A review

Anglo American Platinum has invested strongly in its mineralogical capability in recent years, taking advantage of the advances in hardware and software in the last decade. Currently, the Anglo American research facility in Johannesburg has 15 MLA and 5 Qemscan instruments in operation. These machines provide support to Anglo American Platinum Concentrator operations. A comprehensive monthly composite sample analyses programme was initiated in 2004 to support a drive to improve metals’ extractions and to enhance product specification—the feedstock to the downstream smelting stage. Over the last 20 years, the ore profile mined by the group’s mining operations has changed significantly with the proportion of UG2 reef and Platreef growing exponentially—the easier to process Merensky reef proportion has dropped to low levels in the same period. UG2 and Platreef Concentrator extractions are compromised by the more ‘difficult’ mineralogy—finer platinum group minerals (PGMs) and larger proportion of dissociation from sulfides. Guided by process mineralogy a change in processing technology has resulted—driven by the pressure to maintain or improve metal-extraction efficiencies. The recent adoption of stirred milling employing ceramic media has proven to be a ‘step change’ process step to meet this objective. A total of 23 stirred milling units have been installed and commissioned in the period 2003–2009 at the majority of Anglo American Platinum Concentrator plants. The development of a large-scale IsaMill™ unit—10,000 L with 3 MW of installed drive power—was a milestone decision allowing the economic mainstream application of stirred milling to follow shortly afterwards when a suitable ceramic grinding medium was identified. The mill scale-up was a successful partnering initiative with Anglo American Platinum working closely with Xstrata Technology of Australia and the manufacturers Netzsch Feinmahltechnik GmbH. A period of flow-sheet evolution guided by process mineralogy in the last decade has led to a new process flowsheet at the UG2 Concentrators. The impact of this flowsheet has led to a step change in PGM metal recoveries. Since the mainstream regrind circuit additions or ‘MIG’ stirred milling applications have settled in after an early operational ramp-up and learning period, UG2 recoveries at the two main production units of Anglo American Platinum—the Rustenburg and Amandelbult mining sites—have increased by more than 5%. This is the largest step change increase in these operations’ history. Further improvement and flow-sheet modification guided by process mineralogy are confidently expected in the next decade.

The Bayan Obo is the largest carbonatite-type rare earth deposit in the world. It not only has a large amount of light rare earth element (LREE) resources but also hosts approximately 9 million tons of medium and heavy rare earth element (M+HREE) resources. However, the M+HREE resources have not received enough attention, which hinders their further utilization. In this study, we conduct a systematic investigation of the distribution and process mineralogy properties of M+HREE in different types of ores in the Bayan Obo deposit. The high-value area (>0.1%) of M+HREE elements is found concentrated in the central and deeper parts of the Main and East orebodies. The content of M+HREE varies among different types of ores, with the Aegirine type (1005 ppm) and Fluorite type (1204 ppm) showing a higher average M+HREE concentration. The minerals rich in M+HREE include bastnäsite, monazite, Ca-fluorocarbonate, Ba-fluorocarbonate, allanite, aeschynite, and fergusonite, each with concentrations exceeding 4000 ppm. Aeschynite and fergusonite, in particular, exhibit high M+HREE concentrations and are enriched in fluorite-type and aegirine-type ores. Analysis of the mixed raw ores from the production line at the concentrating plant reveals an M+HREE concentration of approximately 0.2% and a concentration of the seven target minerals at around 12%. However, the particle size distribution and monomer dissociation degree are limited to below 22.3 µm and 40%, respectively. Based on these integrated analyses, we propose that the fluorite-type and aegirine-type ores within the Main and East open-pits are potential M+HREE targets. Furthermore, the recycling and utilization of M+HREE resources in the Bayan Obo deposit require a well-structured process flow and the selection of advanced processing equipment in the future.

Refractory iron ore is often discarded as tailings. This causes a great waste of iron resources. In this paper, the flash roasting-magnetic separation process was designed by combining the magnetic separation process of magnetite and the process mineralogy of iron tailings. The flash suspension roasting effects with 3–4 s roasting time were evaluated by magnetic separation. The MLA results show that the tailings are ground to a fineness of P90 −75 μm, where the distribution of siderite and M/H in the −75 μm particle size is 85.37% and 92.75%, respectively. Moreover, M/H and siderite are mainly associated with muscovite and quartz. This indicates that regrinding for contiguous bodies of M/H and siderite is beneficial for improving the grade and recovery of iron concentrates. The results of the flash roasting-magnetic separation process show that a mixed iron concentrate containing 60.10% Fe with an iron recovery of 81.13% would be achieved after selective grinding and staged magnetic separation of the roasted ore. The result indicates that the flash suspension roasting effects with 3–4 s roasting time are achievable. The study provides an efficient approach for recovering refractory iron from tailings.

The significance of applied or process mineralogy in the minerals industry has been fully recognized only in the last ten years. The various mineralogical techniques that are routinely applied by economic geologists and mineralogists to the study of ores can be very usefully applied to the solution of a wide variety of industrial problems and to the improvement of the efficiency of those industrial processes. Publications dealing with applications of process mineralogy have been connected principally with presentations before three professional organizations.

In this paper, a typical zinc sulfide concentrate has been studied in detail by process mineralogy. Its main mineral composition and occurrence state of elements were identified. In addition, the effects of technological conditions such as temperature and acidity on the pressure leaching were investigated. The phase transformation of iron was analyzed and the related mechanism was explained. At the same time, the latest experimental progress in the field of zinc pressure leaching, such as leaching process, leaching kinetics, elemental behavior, and phase transformation in the process of pressure leaching, is also introduced.

Understanding the performance of a pilot vermiculite exfoliation system through process mineralogy

Feasibility Assessment of X-Ray Transmission (XRT) Sorting for Gold Ores Based on Process Mineralogy: Targeting Gold-Hosting Minerals

In order to improve the reasonable utilization of mineral resources and reduce unnecessary energy consumption in the process of mineral processing, the study of ore technological properties provides a theoretical basis for this purpose. This subject conducted a process mineralogy study on a mine in Xinping County, Yunnan Province and found that the ore's valuable element is iron with a grade of 28.98wt.%. And the main iron-bearing minerals are magnetite, ilmenite and limonite. Iron-bearing minerals are embedded in the ore with a finer grain size. According to the nature of the ore, a reasonable technological process for sorting the ore was determined. The iron concentrate with a grade of 60.32wt. % was obtained. The recovery rate of valuable element iron in the concentrate is 75.72%, and the beneficiation index is good. The results show that the study of process mineralogy has a strong guiding significance for beneficiation production.

The grade of the crude hematite-limonite ore is 39.79%. The main metallic minerals are hematite-limonite. Hematite has disseminated structure distributed in the gangue. Limonite was inlayed as stars in hematite. Due to their fine dissemination and close association with gangue minerals, the hematite and limonite particles are hard to be fully liberated, bringing difficulty in their separation. Staged grinding-separation process consisting of high intensity magnetic separation and reverse floatation wag adopted in the beneficiation test on the regionally representative hematite—limonite ore resource. At a grind of 70.0% -200 mesh for the primary grinding and 98.7% -200 mesh for the secondary grinding, the final iron concentrate grade 58.26% and having an iron recovery of 8.33% can be achieved after reverse flotation process test on magnetic concentrate.

Titanium-bearing blast furnace slag is an important resource among the by-products of the steel industry, and the recycling of titanium elements holds significant economic and environmental importance. This study conducts a detailed process mineralogy analysis of Panzhihua-Xichang titanium-bearing blast furnace slag samples, exploring the mineral composition, occurrence state of titanium elements, the dissemination characteristics and particle size distribution of the main titanium-bearing minerals, as well as micro-area composition analysis of titanium elements. The research findings indicate that ilmenite and perovskite are the primary titanium-bearing minerals in the samples, with titanium elements mainly residing in these two minerals. Through analysis of the particle size distribution and degree of liberation, potential pathways for enhancing the recovery rate of titanium elements are proposed, providing a theoretical basis for the resource utilization of titanium-bearing blast furnace slag.

This study aims to investigate the process mineralogy of the Dishui copper ore in Xinjiang and determine the flotation kinetic equations of this copper ore during the sulfuration flotation process. The results indicate cuprite is the main form of oxide copper minerals, which is difficult to be vulcanized and floated. The fitting of flotation date to a flotation kinetic equation shows that the copper oxide ore, cuprite, malachite and chrysocolla in this ore are consistent with a first order kinetic equation. The rate constants for copper oxide, cuprite, malachite and chrysocolla are 0.152, 0.104, 0.248 and 0.210 respectively. Thus, the flotation of cuprite in the ore is very important to improve the total recovery of the copper oxide ore.

Mineralogical characterization of an ore deposit is an essential on-going activity in a continuum of evaluation exercises and decisions which operate from the very first recognition of mineralization to the cessation of mining and beyond. The main input of the mineralogist to ore evaluation is through the provision of a detailed qualitative and quantitative mineralogical representation of an ore that is specifically targeted to the needs of the process engineer in determining metallurgical recovery, especially during the exploration and pre-production stage. This process mineralogical input is often related to fine-tuning in mining and processing resulting from unexpected variations in the mineralogy of the ore to the mill. Mineralogical characteristics of platinum ore, refractory gold ores, and complex Cu-Zn-Pb ores are used to illustrate aspects of process mineralogical input at various stages in the life cycle of a mine. It is concluded that it is difficult for the mineralogist to become established as an essential and ongoing participant of exploration and mine evaluation exercises. It is thus important that both process engineers and geologists are given a better training in process mineralogy than is presently the case. Most mineralogical training and research in geology departments is exclusive of industrial applications.

The Fen carbonatite complex, situated in Vestfold and Telemark County, South Norway, is one of the largest known rare earth elements (REE) deposits in Europe with ongoing exploration drilling. Literature regarding the complex processing of the Fen ore is lacking, and thus, the present work investigates for the first time its beneficiation potential and applies process mineralogy studies to understand in a sound manner the performance variations during the processing of REE ore. Flotation kinetics studies revealed that (i) high concentration of total REE-oxide (TREO) can be achieved during rougher flotation; (ii) the high concentration of sulphur (in form of pyrite as main sulphide) can be achieved at the beginning of flotation; (iii) the highest concentration of TREO can be reached after flotation of S. Further processing (i.e., by the addition of cleaning stages and grinding) has a potential to improve the overall recovery of TREO and S. However, the decision of further processing will depend, among other factors, on the definition of following hydrometallurgical routes (e.g., leaching, solvent extraction) and the economic aspects of the overall process. So far, the reported results show that a rather flexible process can be achieved for the material from the Fen deposit.