The Separation of Carbonaceous Matter from Refractory Gold Ore Using Multi-Stage Flotation: A Case Study

As a pre-treatment method of refractory gold ore, carbonaceous matter (C-matter) flotation was investigated with multi-stage flotation by rougher, scavenger, and cleaner stages. Different dosages of kerosene and MIBC (4-Methyl-2-pentanol) were applied and the optimum dosage was selected by testing in each flotation stage. With the combination of each stage, four circuit designs were suggested, which were a single-stage rougher flotation (R), rougher-scavenger flotation (R+S), rougher-scavenger-scavenger cleaner flotation (R+S+SC), and rougher-rougher cleaner-scavenger-scavenger cleaner flotations (R+S+RC+SC). The results indicated that the scavenger flotation increased C-matter recovery but reduced C-matter grade compared with single-stage rougher flotation. Cleaning of the scavenger flotation concentrate improved C-matter grade significantly, but reduced recovery slightly. Cleaning of the rougher flotation concentrate achieved overall improved selectivity in flotation. A combination of rougher-scavenger flotation followed by cleaning of both concentrates (R+S+RC+SC) resulted in 73% C-matter recovery and a combined cleaner concentrate grade of 4%; the final tailings C-matter grade was 0.9%, where the C-matter remaining in the tailings was locked, and fine grained. The results demonstrate the need for the multi-stage flotation of C-matter from refractory gold ore to achieve selective separation and suggested the potential of C-matter flotation as the pre-treatment for efficient gold production.

Decoupling the effects of alteration on the mineralogy and flotation performance of Great Dyke PGE ores

Ores from a single deposit may exhibit extensive variability in their mineralogy and texture. The ability to quantify this variability and link it to mineral processing performance is one of the primary goals of process mineralogy. This study focuses on the effect of alteration in three platinum group element ore samples from the Great Dyke in Zimbabwe - two of which were more pristine compared to the third, which was locally classified as 'oxidized' ore. These ores are known to be characterized by varying degrees of alteration, resulting in numerous challenges in flotation and affecting both grade and recovery. Alteration, by near-surface oxidation, of the valuable base metal sulphides and platinum group minerals resulted in lower flotation recoveries of Cu, Ni, Pt, and Pd. Evidence of incipient oxidation was more readily observed in the base metal sulphide assemblage than the platinum group mineral assemblage, even though the loss in recovery (because of oxidation) was most significant for Pd. Alteration through hydration resulted in a significant increase in mass pull and dilution of concentrate grade through the inadvertent recovery of naturally floating gangue comprising composite orthopyroxene and talc particles. In this study, the amount of naturally floating gangue was more strongly correlated with the talc grain size distribution than the grade of talc in the flotation feed. The oxidation and hydration alteration reactions are not necessarily mutually exclusive, although one may be more dominant than the other, giving rise to ore variability.

Multi-Objective Optimization of Forth Flotation Process: An Application in Gold Ore

In order to improve production control ability in the gold ore flotation process, the output index in this process was studied. Flotation is an effective gold recovery process. Gold concentrate grade and gold recovery rate are the key output indicators of the flotation process. However, in the existing studies exploring the impact of parameter changes on the output indicators, the control ability of the output indicators is insufficient, and the interaction between variables is inadequately considered. Therefore, a multi-objective optimization model based on response surface methodology and the non-dominated sorting genetic algorithm-II (NSGA-II) is proposed in this paper. Firstly, the experiment was designed based on the Box-Behnken principle. Based on the experimental results, the interaction between variables was analyzed and the response polynomial was fitted. Secondly, a multi-objective optimization model was constructed, and the NSGA-II was used to solve the model. Finally, an example of gold ore flotation was used to verify the effectiveness of the method. The optimal solution was a gold concentrate grade of 75.46 g/t and a gold recovery rate of 85.98%.

Control of Sulfide Oxidattion and its Effect in Galena Flotation

Pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite (ZnS) and galena (PbS) generate hydrogen peroxide (H2O2) when placed in water, that pyrite the most amount of H2O2. The order of these minerals for generate of H2O2 in presence water is pyrite > chalcopyrite > sphalerite > galena. In the previous research, the methods of generation of H2O2 in the grinding mill have been studied but its effect on the oxidation of pulp components and hence in deteriorating the concentrate grade and recovery in flotation has not been explored yet. In this study, some parameters investigated to control the deleterious effects of H2O2 in flotation. The data from experimental have been attached by using MODDE 9 software for 6 parameters consist of composition of water, grinding media, particle size, pH, adding collector among the grinding, adding depressant. Finally, the optimize condition has been achieved: particle size 75 μ, process water, adding all collector, without depressant and pH 10. These changes in flotation response of sulphides have been discussed and explained with the formation of H2O2 quantitatively and the results are presented and discussed in terms of H2O2 generation vis-à-vis concentrate grade and recovery in flotation.

The Recovery and Concentration of Spodumene Using Dense Media Separation

In coming years, global lithium production is expected to increase as the result of widespread electric vehicle adoption. To meet the expected increase in demand, lithium must be sourced from both brine and hard-rock deposits. Heavy liquid separation (HLS) and dense media separation (DMS) tests were conducted on the pegmatites from Hidden Lake, NWT, Canada to demonstrate the potential role of this technology in the concentration of spodumene (LiAlSi2O6) from hard-rock sources. A continuously operated DMS circuit test, conducted on +840 µm material, produced a concentrate grading 6.11% Li2O with ~50% lithium recovery. The circuit rejected 50% of the original mass to tailings, with only 8% lithium losses. Sensitivity analysis showed that minor changes (+/−0.05) in the DMS-specific gravity cut point resulted in significant changes to the mass rejected and to the concentrate grade produced; this may limit the feasibility and operability of the downstream grinding and flotation circuits. The results demonstrate the potential for DMS in the concentration of spodumene from the Hidden Lake pegmatites, and by extension, the potential for DMS in the concentration of spodumene from other hard-rock occurrences.

Fine hydraulic screening for staged separation of titanium-magnetite concentrate

This article covers the applications of fine hydraulic screening for the staged separation of titanium-magnetite concentrates upstream of the last grinding stage and provides an evaluation of its process efficiency options for the Kachkanarsky GOK. In all screen operating modes tested, the mass fraction of iron in the undersize was higher than its mass fraction in the oversize, but failed to reach the target value for the concentrate of 61 %. Therefore, the undersize must be subjected to additional magnetic concentration. Staged separation of the concentrate by fine screening allows either to improve concentrator performance (by up to 10 %) or to increase the concentration process indicators without changing the grinding equipment volume. In this case, the undersize yield averages 55 %. The use of the staged concentrate separation technology with fine screening at constant process parameters and steady factory performance allows reducing the tertiary mill volume in relative terms, not exceeding half of the undersize yield from the operation, which shall be 65–70 %. The minimum permissible values of the mass fraction of iron and of the –0.071 mm class in the screen feed and the undersize must be ensured for obtaining the required concentrate grade. The values of these indicators depend on the material composition of the ore and the concentration process used.

Reverse Combined Microflotation of Fine Magnetite from a Mixture with Glass Beads

Magnetite is an essential iron-bearing mineral. The primary method of magnetite ore beneficiation involves successive steps of crushing, grinding, and magnetic separation. Reverse cationic flotation is used at the final stage to remove silicate and aluminosilicate impurities from the magnetite concentrate and reduce silica content to 1–3%, depending on metallurgical processing route (electrometallurgy, direct iron reduction). In view of the stringent demands of the magnetite concentrate grade, before flotation, the ore is currently routinely ground down to a particle size below 35 µm, and magnetite particles are ground to a size below 10 µm. This significantly reduces the efficiency of flotation and increases iron loss in the tailings due to the hydraulic report in froth being up to 15–25%. Combined microflotation (CMF) looks to be a promising method of increasing fine-particle flotation efficiency, as it uses relatively small amounts of microbubbles alongside conventional coarse bubbles. Microbubbles act as flotation carriers, collecting gangue particles on their surface, which then coarse bubbles float. The purpose of this study is to explore the effectiveness of CMF for processing a model mixture that contained magnetite particles smaller than 10 µm and glass beads (Ballotini) below 37 µm in size when the initial iron content in the mixture was 63.76%. Commercial reagent Lilaflot 821M was used as both collector and frother. The flotation procedure, which included the introduction of 15 g/t of the collector before the start of flotation, and the addition of 5 g/t of the collector in combination with a microbubble dose of 0.018 m3/t 6 min after starting flotation, ensured an increase in the concentrate grade to 67.63% Fe and iron recovery of 91.16%.

Simulating the Effect of Water Recirculation on Flotation through Ion-Spiking: Effect of Ca2+ and Mg2+

Froth flotation is a multifaceted complex process which is water intensive. The use of recycled water as an alternative source of water to meet water demands of the process may introduce deleterious inorganic ions that affect the mineral surface, pulp chemistry, and reagent action, hence the need to establish whether threshold ion concentrations exist beyond which flotation performance will be adversely affected. This is of paramount importance in informing appropriate recycle streams and allowing simple, cost-effective water treatment methods to be applied. Here we report that increasing ionic strengths of synthetic plant water (SPW); 3, 5, and 10 SPW respectively, resulted in an increase in water recovery in the order 0.073 mol·dm−3 (3 SPW) < 0.121 mol·dm−3 (5 SPW) < 0.242 mol·dm−3 (10 SPW), indicating an increase in froth stability as higher water recoveries are linked to increased froth stabilities. This behavior is linked to the action of inorganic electrolytes on bubble coalescence which is reported in literature. There was, however, no significant effect on the valuable mineral recovery. Spiking 3 SPW to 400 mg/L Ca2+ resulted in higher copper and nickel grades compared to 3 SPW, 5 SPW, and 10 SPW and was deemed to be the Ca2+ ion threshold concentration for this study since 3 SPW spiked with further Ca2+ to a concentration of 800 mg/L resulted in a decrease in the concentrate grade. The spiking of 3 SPW with Mg2+ resulted in higher copper and nickel grades compared to all other synthetic plant water conditions tested in this study.

A Novel Pneumatic Planar Magnetic Separator for Magnetite Beneficiation: A Focus on Flowsheet Configuration

In our previous studies, we investigated the performance of a novel pneumatic planar magnetic separator (PMS) for the dry beneficiation of a selected magnetite ore. In the present study, we have extended the studies on the PMS with the focus on investigating how various PMS processing flowsheet configurations influence its performance. The outcomes were subsequently compared with those of a Davis tube recovery (DTR) tester. The study demonstrated that the use of PMS in the dry beneficiation of magnetite ores is feasible, and operating the PMS in different flowsheet configurations positively influences the magnetite concentrate grade and purity. Finally, the study showed that the PMS performance compares well with that of DTR and can potentially replace DTR in operations that are carried out in arid regions.