Effect of Temperature on Biobeneficiation of Bulk Copper-Nickel Concentrate with Thermoacidophilic Microbial Communities

Bioleaching of the bulk copper–nickel sulfide concentrate was proposed as a method to remove nickel from it and to obtain a concentrate containing copper as chalcopyrite. This approach is based on the different refractoriness of sulfide minerals in ferric sulfate solutions and oxidation by acidophilic microorganisms. The bulk concentrate contained 10.8% copper in the form of chalcopyrite (CuFeS2) and 7.2% nickel that occurred in pentlandite ((Ni,Fe)9S8) and violarite (FeNi2S4). Three microbial communities grown at 35, 40, and 50 °C were used for bioleaching. The microbial community at 40 °C was the most diverse in the genus and species composition. At all temperatures of the process, the key roles in bioleaching belonged to mixotrophic and heterotrophic acidophiles. The highest levels of nickel leaching of 97.2 and 96.3% were observed in the case of communities growing at 40 and 50 °C, respectively. At the same time, the bioleach residue, which could be characterized as a marketable high-grade copper (chalcopyrite) concentrate, was obtained only at 40 °C. This solid contained 15.6% copper and 0.54% nickel. Thus, the biobeneficiation of bulk sulfide concentrates can be a promising field of biohydrometallurgy.

Pengaruh Karakteristik Bijih pada Ekstraksi Nikel dari Bijih Limonit Indonesia menggunakan Pelindian Atmosferik

AbstrakKebutuhan ekstraksi nikel dari bijih nikel laterit khususnya jenis bijih limonit dengan kadar nikel yang rendah sangat diperlukan karena kebutuhan nikel yang terus meningkat dengan adanya pengembangan kendaraan bermotor listrik berbasis baterai. Jenis dan karakteristik bijih laterit yang berbeda akan memberikan pengaruh pada hasil ekstraksi nikel. Pada penelitian ini dilakukan ekstraksi nikel dari bijih laterit jenis limonit yang berasal dari Pulau Halmahera (LH)) dan Pulau Sulawesi (LS) menggunakan pelindian atmosferik. Asam sulfat digunakan sebagai agen pelindian. Penelitian dilakukan untuk mengetahui pengaruh karakteristik bijih limonit (LH dan LS) pada berbagai variabel pelindian yaitu suhu (30oC, 50oC dan 80oC), konsentrasi asam sulfat (0,5M; 1M; dan 2M), waktu pelindian (15, 30, 60, 120, dan 240 menit), serta rasio bijih terhadap reagen pelindian (5, 10, dan 20% w/v) terhadap ekstraksi nikel dari bijih limonit. Hasil penelitian menunjukkan bahwa karakteristik bijih laterit sangat berpengaruh pada hasil pelindian dan persen rekoveri nikel. Nikel dari bijih LH yaitu jenis limonit dari Pulau Halmahera dapat diekstrak secara maksimal (100%) pada konsentrasi asam sulfat 0,5M, suhu 80oC, rasio bijih/larutan asam sulfat 10%, dan waktu pelindian 2 jam. Sedangkan persen ekstraksi nikel dari bijih LS yang terbesar adalah 95% yang diperoleh pada konsentrasi asam sulfat 2M, suhu 80oC, rasio bijih/larutan asam sulfat 5%, dan waktu pelindian 4 jam. AbstractNickel extraction from nickel laterite ores particularly low-grade limonite ore is needed along with the increase of nickel consumption on the development of battery electric vehicle. Types and characteristics of nickel laterite ores affect greatly on the nickel extraction from these ores. This research conducted the extraction of nickel from limonite ore from different areas i.e. Halmahera Island (LH) and Sulawesi Island (LS) using atmosferic leaching. Sulfuric acid (1M) was used as leaching reagent. Leaching processes were carried out for investigating the effects of limonite ore characteristics (LH and LS), leaching temperatures (30oC, 50oC dan 80oC), concentration of sulfuric acid (0.5M; 1M; 2M), leaching time (15, 30, 60, 120, and 240 minutes), and ratio of ore amount to volume of leaching reagent on the nickel extraction from limonite ores. Experimental results showed that ore characteristic affected greatly on the leaching result and nickel leaching recovery. Nickel from LH ore could be extracted maximum (100%) using sulfuric acid 0.5M, temperature of 80oC, and leaching time 120 minutes (2 hours). Whereas, the highest nickel extraction percentage from LS ore is 95% using sulfuric acid 2M, temperature of 80oC, and leaching time 240 minutes (4 hours).

Study of Nickel Leaching Using Sulfuric Acid and Phosphoric Acid on The Selectivity Nickel Ore

Study of nickel leaching using sulfuric acid and phosphoric acid on the selectivity of low-grade laterite nickel ore under atmospheric conditions has been successfully carried out. In this study, the laterite nickel leaching process was carried out by varying the solution concentration and operating time. The concentrations of sulfuric acid and phosphoric acid solutions were varied at 5 M and 6 M concentrations, while the operating time was varied at 4 hours and 6 hours. For other operating conditions, it is kept constant with an operating temperature of 90 ℃, pulp density 15% w / v, particle size ≤ 200 mesh. After that, the analysis stage was carried out using an atomic absorption spectroscopy (AAS) tool to determine the nickel content in the sample. The results showed that the highest nickel recovery was obtained at the concentration of 5 M sulfuric acid solution of 2.60% and 5 M phosphoric acid of 2.59% with the optimum operating time at 4 hours of operating time.

Modeling Nickel Leaching from Abandoned Mine Tailing Deposits in Jøssingfjorden

Underwater disposal of mine tailings in lakes and seas has been considered favorable due to the geochemical stability obtained during long-term storage in anoxic sediments. Sulfides are stable in the ore; however, oxidation and transformation of some substances into more soluble forms may impact bioavailability processes and enhance the risk of toxic effects in the aquatic environment. The goal of this work was to construct a model for simulating the nickel (Ni) cycle in the water column and upper sediments and apply it to the mine tailing sea deposit in the Jøssingfjord, SouthWest Norway. A one-dimensional (1D) benthic–pelagic coupled biogeochemical model, BROM, supplemented with a Ni module specifically developed for the study was used. The model was optimized using field data collected from the fjord. The model predicted that the current high Ni concentrations in the sediment can be a potential source of Ni leaching to the water column until about 2040. The top 10 cm of sediments were classified as being of “poor” environmental state according to the Norwegian Quality Standards. A numerical experiment predicted that with complete cessation of the discharges there would be an improvement in the environmental state of sediment to “good” in about 20 years. On the other hand, doubling of discharge would lead to an increase in the Ni content in the sediment, approaching the boundary of the “very poor” environmental state. The model results demonstrated that Ni leaching from the sea deposits may be increased due to sediment reworking by bioturbation at the sediment–water interface. The model can be an instrument for analysis of different scenarios for mine tailing activities from point of view of reduction of environmental impact as a component of the best available technology.

The Effects of Milling and pH on Co, Ni, Zn and Cu Bioleaching from Polymetallic Sulfide Concentrate

Acid bioleaching of a low-grade and polymetallic sulfide concentrate was studied, in order to determine suitable feed material particle size and pH for efficient leaching of valuable metals. The sulfide concentrate consisted of pyrite (50 wt %), pyrrhotite (31 wt %), quartz (10 wt %) and lower amounts of cobalt, nickel, zinc and copper (each <1 wt %). After adaptation of microorganisms in shake flasks, stirred tank tests were conducted at different pH levels and supplementing feed material at different particle sizes (milled to d80 < 150 µm, <50 µm, <28 µm, <19 µm). The operation at pH 1.8 was seen prone to iron precipitation, while this was not observed at a pH between 1.3 and 1.5. Additional milling to decrease particle size from the initial d80 < 150 µm had a major positive effect on cobalt- and nickel-leaching yields, proposing that at least d80 < 28 µm should be targeted. The best leaching yields for the main economic elements, cobalt and nickel, were 98% and 94%, respectively, reached with d80 < 19 µm at pH 1.3. However, it was considered that at pH 1.5, similar results could be obtained. This research sets the basis for continuing the experiments at a continuous pilot scale.

Study on the effect of microwave roasting pretreatment on nickel extraction from nickel-containing residue using sulfuric acid

Various means have been proposed to solve problems such as high ash content and complex composition in the recycling of nickel-containing residue produced by battery manufacturing enterprises. Microwave roasting pretreatment is proposed to improve the nickel leaching rate from the residue. The effect of different experimental conditions like microwave roasting temperatures, roasting times, and microwave powers on the nickel leaching rate was studied. It was found that the effect of roasting temperature on the nickel leaching rate was more significant than those of roasting time and microwave power. Meanwhile, after microwave roasting pretreatment, the rate of nickel leaching from the residue could be increased by 20.43%, and weight of the material could also be reduced by more than 21%. After microwave roasting at 450°C, there was no significant change in the main phases of the material, but the surface of the particles exhibited an apparent stratified dissociation phenomenon. Response surface methodology (RSM) was used to optimize the parameters of microwave roasting with nickel leaching rate as the response value. The results showed that the nickel leaching rate could reach 93.11% for roasting at the microwave power of 962 W for 6.2 min under the temperature of 452°C.