Search Results (5)

Custom copper smelters, which are dependent on purchased concentrates, are facing increasing economic pressures amid falling treatment and refining fees. With the declining availability of high-grade, low-impurity concentrates, copper demand is expected to surge to support the transition to renewable energy. This study, which is based on recent observations of Chinese custom smelters, examines their strategies to address the challenge of purchasing concentrates at record-low treatment and refining charges. By investing in slag flotation technology, smelters can enhance copper, gold, and silver recovery. By blending high-grade and low-grade concentrates, they can capitalize on the gap between the recoverable and payable metals, which are often referred to as “free metals”, while also benefiting from byproducts, mainly sulfuric acid. While this approach offers economic opportunities, it introduces operational complexities. To mitigate these, laboratory testing, combined with advanced digital predictive tools based on thermodynamics, is crucial. This study demonstrates the use of thermodynamic models supported by experimental work for analyzing furnace operations. FactSage^® software and a custom database are employed to define the operating window of two common flowsheets: (1) flash smelting + flash converting and (2) bottom-blown smelting + bottom-blowing converting. Full article

The present work investigates a comparative study between mechanical and Imhoflot^TM cells on a mini-pilot scale and the applicability of one self-aspirated H-16 cell (hybrid Imhoflot^TM cell) on an industrial scale on-site. The VM-04 cell (vertical feed to the separator vessel with 400 mm diameter) was fabricated, developed, and examined. The copper flotation experiments were conducted under similar volumetric conditions for both the Imhoflot^TM and mechanical flotation cells keeping the rest of the parameters constant. Further, one H-16 cell was positioned at four different stages in the Gökirmak copper flotation circuit of the Acacia (Türkiye) copper beneficiation plant, i.e., at (i) pre-rougher flotation, (ii) rougher concentrate, (iii) cleaner-scavenger tailing, and (iv) first cleaning concentrate aiming at enhancing the flotation circuit capacity through flash flotation in the rougher stage, reducing copper grade in the final tailing, and increasing cleaning throughput, respectively. Comparative copper flotation tests showed that ultimate recoveries using the Imhoflot^TM and mechanically agitated conventional cells were 94% and 74%, respectively. The industrial scale test results indicated that locating one pneumatic H-16 cell with the duty of pre-floating (also known as flash flotation) led to the enrichment ratio and recovery of 4.84 and 89%, respectively. Positioning the H-16 cell at the cleaner-scavenger tailings could diminish the copper tailings grade from 0.43% to 0.31%. Further, a relatively greater enrichment ratio and copper recovery were obtained using only one Imhoflot^TM cell (1.76 and 64%) in comparison with employing four existing mechanical cells (50 m³, each cell) in series (1.45 and 60%) at the first cleaner stage. Full article

Annually, hundreds of thousands of tons of slags are involved in the reverberator and flash smelting as well as converting operations of Cu-Fe sulfide concentrates to produce matte in the Sar Cheshmeh copper smelter plant, Iran, disposed in the landfill and cooled in air. Due to their relatively high average copper content (about 1.5 wt%), a mineral processing plant based on the flotation process has recently been established to produce thousands of tons of Cu-sulfide concentrate after slag crushing and fine grinding operation. In order to make the flotation process more efficient, more knowledge is required on the form and origin of the copper losses in the slag. To achieve this, mineralogical studies of the slags using optical microscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) methods have been carried out. Mineralogical analyses showed the main part of copper losses into the semi- to fully-crystallized magnetite-rich reverberator and flash slags characterized by crystal–glass matrix ratio ≤ 1 is moderate to coarse particles of Cu-Fe sulfides, i.e., chalcopyrite (CuFeS₂) and bornite (Cu₅FeS₄), that are mainly chemically entrapped. In contrast, the mechanically entrapped fine- to coarse-grain (from 20 up to 200 µm) spherical-shaped of high-grade matte particles with chalcocite (Cu₂S) composition containing droplets or veinlets of metallic copper (Cu⁰) are the dominant forms of copper losses into the converter slags characterized by crystal–glass matrix ratio > 1. From the value recovery point of view, our result show that the fully crystallized slags containing moderate- to coarse-grain copper-bearing particles will result in efficient recovery of a significant amount of entrained copper due to better milling response compared to semi-crystallized ones due to locking the fine- to moderate-grain copper particles in the silicate glassy matrix. Laboratory-scale grinding experiments showed that normal (≤74 μm) to fine (≤44 μm) grinding of high- Cu grade slags lead to a significant increase in the liberation degree of copper particles. in contrast, the increase in fine particle fractions (<37 μm) due to re-grinding or ultra-fine grinding of the originally low-Cu grade slags does not lead to the liberation of copper particles, but it will reduce the efficiency of the flotation process. This study suggests that the highest rate of copper recovery of the slag by the flotation process will be obtained at particle size 80% passing 44 µm which has also reached the optimal liberation degree of copper-bearing particles. Full article

Intimate knowledge of the mineralogical assembly of the Yushui complex ore rich in Cu, Pb, and Ag is essential if efficient separation processing is to be conducted. With the aid of testing instruments, such as scanning electron microscope (SEM), X-ray diffractometer (XRD), and mineral liberation analyzer (MLA) combined with energy-dispersive X-ray analysis (EDX), the texture, such as the size distribution, dissemination, and association of the minerals, was investigated. The results demonstrate that the ore consists of 35 categories of minerals, assaying Cu 7.99%, Pb 9.39%, and Zn 1.96% in the forms of chalcopyrite, galena, and sphalerite, respectively, and silver assaying 157.9 g/t is closely associated with these sulfides; sulfides are present in amounts of 80.31% of the total, traditional gangues only 19.69%, and pyrite as a Cu-Pb-Zn-Ag carrier mineral up to 44.80%. According to the characteristics of the ore, the innovative process of flash copper flotation in weak acidic pulp and lead flotation, followed by further copper recovery, was developed. The closed-circuit test shows that copper concentrate assays Cu 16.33%, Pb 7.98%, Ag 242 g/t at Cu recovery of 86.67%; lead concentrate contains Pb 46.23%, Cu 3.75%, Ag 165 g/t at Pb recovery of 56.84%; total recovery of silver in both concentrates is 75.57%. Full article

High-phosphorus oolitic iron ore, treated by suspended flash magnetic roasting, contained 42.73% iron (mainly present as magnetite) and 0.93% phosphorus (present as collophane). Low-intensity magnetic separation (LIMS) was combined with reverse flotation to increase the iron and reduce the phosphorus contents of the roasted product. The results showed that an optimized iron ore concentrate with an iron grade of 67.54%, phosphorus content of 0.11%, and iron recovery of 78.99% were obtained under LIMS conditions that employed a grind of 95% −0.038 mm and a magnetic field of 0.10 T. Optimized rougher reverse-flotation conditions used a pulp pH of 9 and dosages of toluenesulfonamide, starch, and pine alcohol oil of 800 g/t, 1000 g/t, and 40 g/t, respectively; optimized scavenging conditions used a pulp pH of 9 and dosages of toluenesulfonamide, starch, and pine alcohol oil of 400 g/t, 500 g/t, and 20 g/t, respectively. Study of the mechanism of phosphorus reduction showed that the toluenesulfonamide could be adsorbed on the surface of quartz after the action of starch, but adsorption was significantly weakened. The starch inhibitor negatively affected adsorption on quartz, but positively influenced adsorption of phosphorus minerals. Full article