This paper compares model predictions from a novel kinetic model with data from five fundamental single-mineral literature flotation datasets. The empirical correlations proposed by Safari and Deglon (2018) are modified to improve their robustness, requiring only a single best-fit regression coefficient per mineral type. Experimental and model-predicted rate constants were compared on a parity chart where a reasonable linear correlation was observed, with a gradient of 0.95 and an overall R² value of 0.97. Thereafter experimental and model-predicted trends from the flotation datasets were compared for particle size, contact angle, agitation, and gas flow rate. Model-predicted trends were reasonably accurate for most of the flotation datasets, but under-predicted the rate constant for larger particles for the data of Pyke (2004). In general model predictions were reasonably accurate, which is considered quite good, as these were obtained by fitting a single parameter per mineral type to several large flotation datasets, totaling 330 rate constants.

Coarse particle flotation (CPF) is one of the strategies employed to reduce energy consumption in mineral-processing circuits. Hydrofloat^TM (HF) technology has been successfully applied in the coarse flotation of industrial minerals and sulphide middlings. However, this technology has not yet been applied in platinum group minerals (PGMs)’ flotation. In this paper, the amenability of platinum group minerals to CPF was investigated. Extensive flotation testwork was conducted to optimise the hydrodynamic parameters, i.e., bed level, air and water flow rates, in the flotation of coarse PGM feed using Hydrofloat. Mineralogical analysis of the feed and selected flotation products was conducted to understand the reasons for the recovery and loss of the valuable minerals. The results showed that the HF separator could upgrade the PGM ore with particles as coarse as +106 − 300 µm. For the optimised test, a reasonable Pt, Pd and Au recovery of 84% was achieved at a grade of 10 g/t and 16.5% mass pull, despite the platinum group minerals being poorly liberated (4.5 vol% fully liberated). The results demonstrated that HF achieved high recovery efficiencies across the 150–300 microns size fraction. The HF was therefore able to substantially increase the upper particle size that can be successfully treated by flotation in PGM operations. It was found that an increase in bed height, water rate and air flow rate resulted in an increase in recovery to a maximum. A further increase in the hydrodynamic parameters resulted in a decline in recovery. Hydrofloat outperformed the conventional Denver flotation machine across the following size fractions: +106 − 150 µm, +150 − 212 µm, +212 − 250 µm and +250 − 300 µm. The practical implications of the findings on the modification of existing circuits and the design of novel flowsheets for the processing of PGM ores with less water and energy consumption are discussed.

Variations in the recovery of platinum group metals (PGMs) are often attributed to mineralogical and other natural ore-type variations. To increase the recovery of PGMs by the flotation process, a comprehensive understanding of gangue and valuable minerals is essential for optimising the extraction and processing of metals. Recoveries may be improved if the questions of how, where, and why losses occur can be answered with a certain degree of confidence. A requirement is the availability of statistically reliable mineralogical data. The PGMs of MG-1–4 chromite tailings dumps of the western limb of the Bushveld complex (BC) were studied in detail to unravel the PGMs and the nature of the platinum group minerals in the sample. Characterisation of the chromite tailings via deportment analysis revealed that the sample contained a significant amount of 3E PGM + Au (Pt, Pd, Ru, and Au) and was concentrated in the -25 µm fraction. The results of automated mineralogical analysis showed that the sample was composed of the PGE-sulphides group, comprising 63.6 vol%, PGE-sulfarsenides 10.4 vol%, PGE-arsenides 1.3 vol%, PGE-bismuth tellurides 3.3 vol%, PGMs-alloy 4.1 vol%, and Laurite comprising 17.3 vol% of the total PGE population. The sample was composed of 66.5 vol% of liberated PGMs, 0.2 vol% attached to liberated BMS, 27.3 vol% of PGMs attached to or locked within silicate or oxide gangue composite particles, 0.2 vol% of PGMs associated with BMS attached to silicate or oxide gangue particles, and a low proportion (5.8 vol%) of PGMs reported being locked within gangue or oxide particles. The majority of PGM grains observed were reported in the fast-floating category (64.4 vol%), 27.6 vol% in the slow-floating 1 category, 2.2 vol% in the slow-floating 2 category, and 5.8 vol% to the non-floating category. The results of the study revealed that the PGMs of MG 1–4 chromite tailings were liberated; however, the low liberation index (<0.2) suggested that a significant portion of PGMs remained trapped within gangue, hindering their recovery. This highlights the need for effective comminution (crushing and grinding) to achieve better liberation. The sample contained fine particles that were more prone to being lost in the tailings and to lowering recovery due to the slimes coating valuable minerals. The recovery of the PGMs from this complex’s polymetallic bodies of low-grade and complex mineralogy will be insufficient with traditional methods and thus innovation is needed. Innovation like advanced comminution, novel flotation equipment or reagents, selective leaching and bioprocessing can overcome these challenges.

This research assesses the effect of carbonated pyrolysis oil (CPO) derived from scrap car tires on the metallurgical efficiency of coal flotation as a flotation additive. Using a statistical experimental design, the influence of various operational variables, including solid percent of feed pulp and dosages of reagents, i.e., CPO as an additive, diesel oil as a collector, and pine oil as a frother, on the ash content and yield of the final concentrate were investigated. Experimental data vary significantly based on operational conditions, ranging from 6.6% ash content with a 15% yield to 19.1% ash content with a 76.8% yield. The composition of the pyrolysis oil was identified by using Fourier transform infrared spectroscopy (FTIR). The analysis of variance (ANOVA) of experimental results demonstrated that almost all variables had a substantial effect on the flotation responses, positive or negative, depending on the variable or variable interaction. It was discovered that the usage of CPO intensified the total yield and ash content of concentrate in a nonlinear fashion in a range of 15% and 4%, respectively. The results revealed a non-selective interaction effect between CPO and pine oil, as well as competitive adsorption between diesel oil and CPO, which contributed to the curved behavior of flotation measurements. The detrimental effect of CPO on the flotation response of the studied coal sample was also related to the interaction of the hydrophilic groups in the CPO structure and the oxide groups of ash material in coal particles. This work shows the potential of carbonated pyrolysis oil to enhance coal flotation performance and sheds light on the underlying mechanisms.

This study introduces a controlled laboratory-scale method for synthesizing barium sulfate, with promising potential for industrial scalability to meet increasing demand for quality and sustainable production. Statistical tools—specifically, design of experiments (DOE) and the D-optimal methodology via DX12.0.3.0 software—were employed to determine optimal reaction parameters. The synthesis process involved the precise control of barium chloride and sulfate concentrations, feed rate, and temperature to ensure the production of barium sulfate. Under optimized conditions (BaCl₂ = 1.5 M, SO₄²⁻ = 0.41 M, flow rate = 2.53 mL/min, temperature = 20.03 °C), a yield of 9.20 g of barium sulfate with a density of 4.25 g/cm³ was achieved. The analysis confirmed the purity of the product, validating its suitability for demanding industrial applications. This approach not only improves product quality but also minimizes waste and reduces operational costs, offering a sustainable and scalable solution for barium sulfate production. These findings mark a meaningful step forward in mineral processing and purification technologies.

With the continuous consumption of mineral resources, ore grades worldwide are declining, and their increasingly fine-grained, low-grade, mineralogically complex, and highly heterogeneous characteristics have led to a marked rise in the energy consumption and processing costs of mineral separation