Process Mineralogy Characteristics and Flotation Application of a Refractory Collophanite from Guizhou, China

A refractory phosphate ore obtained from Guizhou, China, contains high amounts of detrimental metal impurities (e.g., Fe, Al, and Mg) which affect the deep wet processing of phosphorus products before use. In this study, mineralogy parameters of the ore such as mineral composition, disseminated particle size, mineral liberation degree, and intergrowth relationship were investigated using X-ray fluorescence spectrometer (XRF), X-ray powder diffractometer (XRD), and advanced mineral identification and characterization system (AMICS). The mechanism for flotation separation was also discussed. The results showed that the ore was a fine-grained calcareous-siliceous collophanite with high P2O5 grade. The gangue minerals such as quartz, sericite (muscovite), pyrite, and dolomite were finely disseminated and encapsulated by fluoroapatite particles in a rather complex relationship. A double reverse flotation process was carried out based on the separation principle of less flotation and more inhibition. A phosphorous concentrate with a P2O5 grade of 35.53%, SiO2 content of 5.88%, MgO content of 0.91%, sesquioxide (Fe2O3+Al2O3) content of 1.98%, MER value of 8.13%, and phosphorus recovery of 75.04% was obtained. Based on the flotation test results and the analysis of process mineralogy parameters, we concluded that the main causes of difficulty in separation of collophanite are fine disseminated particle size, poor mineral liberation degree, and serious argillization. The selection of foam-controlled collectors, efficient dispersing inhibitors and classified desliming process will be necessary for improving flotation index. These results provide a technical reference for subsequent development and utilization of collophanite resources.

Study on process mineralogy of limonite

In this paper, the process mineralogy, such as the composition and content of elements and minerals, and the chemical composition of main minerals, was studied by the method of mineral liberation analyser. The results show that the ore is limonite bearing-zinc ore, the content of the main mineral limonite is 95.982%, most of limonite is monomeric, a few limonite is associated with pyrite and muscovite, with quartz, with sericite and quartz, limonite contains sericite, synbiote of limonite and sericite. Zinc occurs mainly in limonite, a small amount of zinc in the form of sphalerite, smithsonite and hemimorphite. This study will lay a mineralogical foundation for the follow-up development and utilization of this type of ore.

Flotation and Tailing Discarding of Copper Cobalt Sulfide Ores Based on the Process Mineralogy Characteristics

The mineral composition of copper–cobalt ores is more complex than that of copper sulfides, and it is also difficult to discard tailing efficiently in primary flotation for the fine-grained disseminated of ore. In this work, a mineral liberation analyzer (MLA) was employed to study the characteristics of minerals. As a significant mineralogical characteristic, the liberation degree of useful mineral aggregates was determined after grinding, and a correlation was established between the ore grinding size and mineralogical characteristics. The results showed that the adopted ore occurred in sulfide form. However, the particle size of the mineral’s monomer was fine grained, whereas its aggregate was coarse. The sulfide mineral aggregate obtained after primary grinding was selected as the recovery object, and its mineralogical characteristics, such as liberation degree and particle size, were investigated to promote total recovery in primary flotation. The copper–cobalt sulfide concentration was obtained at the following optimal conditions: the grinding size of −0.074 mm (65%), the aggregate’s liberation degree of 67%, a collector dosage of 50 g·t−1, a collector combination of 35% aerofloat + 65% butyl xanthate, a pH of 8.5, and 2# oil (a terpineol type foaming agent) dosage of 60 g·t−1. The recovered rough Cu and Co concentrates were 89.45% and 88.03%, respectively. Moreover, the grades of Cu and Co were 13.4% and 4.81%, respectively, with 85.07% of the ore weight discarded as tailing. The consideration of sulfide aggregates instead of singeral minerals mineralogy characters in primary grinding and primary flotation provides an effective theoretical guide for the sorting of sulfide minerals and reduction in the power consumption of grinding.

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.

3D Ore Characterization as a Paradigm Shift for Process Design and Simulation in Mineral Processing

Current advances and developments in automated mineralogy have made it a crucial key technology in the field of process mineralogy, allowing better understanding and connection between mineralogy and the beneficiation process. The latest developments in X‑ray micro-computed tomography (µCT) have shown a great potential to let it become the next-generation automated mineralogy technique. µCT’s main benefit lies in its capability to allow 3D monitoring of the internal structure of the ore sample at resolutions down to a few hundred nanometers, thus excluding the common stereological error in conventional 2D analysis. Driven by the technological and computational progress, µCT is constantly developing as an analysis tool and successively it will become an essential technique in the field of process mineralogy. This study aims to assess the potential application of µCT systems, for 3D ore characterization through relevant case studies. The opportunities and platforms that µCT 3D ore characterization provides for process design and simulation in mineral processing are presented.

Configuration of flowsheet and reagent dosage for gilsonite flotation towards the ultra-low-ash concentrate

Gilsonite has a wide variety of applications in the industry, including the manufacture of electrodes, paints and resins, as well as the production of asphalt and roof-waterproofing material. Gilsonite ash is a determining parameter for its application in some industries (e.g., gilsonite with ash content < 5% used as an additive in drilling fluids, resins). Due to the shortage of high grade (low ash) gilsonite reserves, the aim of this study is to develop a processing flowsheet for the production of ultra-low-ash gilsonite (< 5%), based on process mineralogy studies and processing tests. For this purpose, mineralogical studies and flotation tests have been performed on a sample of gilsonite with an average ash content of 15%. According to mineralogical studies, carbonates and clay minerals are the main associated impurities (more than 90 vol.%). Furthermore, sulfur was observed in two forms of mineral (pyrite and marcasite) and organic in the structure of gilsonite. Most of these impurities are interlocked with gilsonite in size fractions smaller than 105 µm. The size fraction of + 105 − 420 µm has a higher pure gilsonite (approximately 90%) than other size fractions. By specifying the gangue minerals with gilsonite and the manner and extent of their interlocking with gilsonite, + 75 − 420 µm size fraction selected to perform flotation tests. Flotation tests were performed using different reagents including collector (Gas oil, Kerosene and Pine oil), frother (MIBC) and depressant (sodium silicate, tannic acid, sulfuric acid and sodium cyanide) in different dosages. Based on the results, the use of kerosene collector, MIBC frother and a mixture of sodium silicate, tannic acid, sulfuric acid and sodium cyanide depressant had the most favorable results in gilsonite flotation in the rougher stage. Cleaner and recleaner flotation stages for the rougher flotation concentrate resulted in a product with an ash content of 4.89%. Due to the interlocking of gilsonite with impurities in size fractions − 105 µm, it is better to re-grinding the concentrate of the rougher stage beforehand flotation in the cleaner and recleaner stages. Finally, based on the results of mineralogical studies and processing tests, a processing flowsheet including crushing and initial granulation of gilsonite, flotation in rougher, cleaner and recleaner stages has been proposed to produce gilsonite concentrate with < 5% ash content.

Configuration of Flowsheet and Reagent Dosage for Gilsonite Flotation Towards the Ultra-Low-Ash Concentrate

Gilsonite is a natural occurrence of bitumen and consists of a complex structure of organic compounds. Gilsonite has a wide variety of applications in the industry, including the manufacture of electrodes, paints and resins, as well as the production of asphalt and roof-waterproofing material. Ash content of gilsonite is a determining parameter for its application in some industries (e.g., ash content <5% as an additive in drilling fluids, Resins). In this study, a process mineralogy approach used in order to design an optimal flotation circuit for the production of gilsonite concentrate with ultra-low ash content (<5%) from gilsonite ore with an average ash content of 15%. According to mineralogical studies, carbonates and clay minerals are the main associated impurities (more than 90 vol.%). Furthermore, sulfur was observed in two forms of mineral (pyrite and marcasite) and organic in the structure of gilsonite. Most of these impurities are interlocked with gilsonite in size fractions smaller than 105 µm. In addition, the size of +105 µm to 420 µm has a higher pure gilsonite (approximately 90%) than other size fractions. The effect of different reagent regime on the production of low ash content concentration in gilsonite flotation are investigated. Based on the results, 400 g/ton of kerosene collector led to the production of a concentrate with the lowest amount of ash (6.36%) in the rougher stage. In addition, the highest amount of recovery (80.83%) were obtained in gilsonite flotation with kerosene collector. The use of depressants in the rougher stage increased the gilsonite recovery by 3.5% and slightly reduced the ash content (less than 0.20%) of gilsonite concentrate. In general, gilsonite flotation with 400 g/ton kerosene collector, 100 g/ton from a mixture of sodium silicate, tannic acid, sulfuric acid and sodium cyanide depressants, and the use of 100 g/ton MIBC resulted in the production of a concentrate with the lowest amount of ash (6.36%) in the rougher flotation stage. Cleaner and recleaner flotation for the rougher flotation concentrate resulted in a product with an ash content of 4.89% and recovery of 86.75%. Due to the interlocking of gilsonite with impurities in size fractions smaller than 105 µm, it is better to re-grinding the concentrate of rougher stage then flotation done in the cleaner and recleaner stages. Finally, flowsheet has been proposed to produce gilsonite with the least ash.

Selective Flotation of Elemental Sulfur from Pressure Acid Leaching Residue of Zinc Sulfide

An efficient flotation process was developed to selectively recover elemental sulfur from a high-sulfur pressure acid leaching residue of zinc sulfide concentrate. The process mineralogy analysis showed that the sulfur content reached 46.21%, and 81.97% of the sulfur existed as elemental sulfur which was the major mineral in the residue and primarily existed as pellet aggregate and biconical euhedral crystal. An elemental sulfur concentrate product with 99.9% of recovery and 83.46% of purity was obtained using the flotation process of one-time blank rougher, two-time agent-added roughers, and two-time cleaners with Z-200 as collector and Na2S + ZnSO4 + Na2SO3 as depressant. The flotation experiment using return water indicated that the cycle use of return water had no adverse effect on the flotation performance of elemental sulfur. The process mineralogy analysis manifested that main minerals in the residue directionally went into the flotation products. Most of elemental sulfur entered the concentrate while other minerals almost completely went into the tailing. Main valuable elements lead, zinc, and silver entered the tailing with sulfides and could be recovered by lead smelting. The proposed process can realize the comprehensive recovery of valuable components in the high-sulfur residue and thus it has wide industrial application prospect.