Effects of forced aeration on community dynamics of free and attached bacteria in copper sulphide ore bioleaching

Yin, Shenghua; Chen, Wei; Ilankoon, I.M.S.K.

doi:10.1007/s12613-020-2125-x

Cited by 21 publications

(4 citation statements)

References 29 publications

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“…The feed solution is initially oxygen-saturated, but oxygen rapidly depletes from the draining solution due to aerobic microbial consumption, making it unavailable further downstream in the process ( Lizama, 2001 ). Additionally, there is a linear correlation between increasing temperature and lower oxygen solubility during bioleaching ( Huang et al, 2022 ) along with air convection and diffusion also decreasing along the length of the column, adversely affecting the oxygen-dependent microbial activity essential for bioleaching and the reaction of oxygen with other iron compounds ( Casas et al, 1998 ; Chen et al, 2022 ). This phenomenon became particularly evident in columns without forced aeration, where we recorded almost negligible sulfur removal at the bottom of the column ( Figure 3 ).…”

Section: Discussionmentioning

confidence: 99%

Establishing a green biodesulfurization process for iron ore concentrates in stirred tank and leaching column bioreactors using Acidithiobacillus thiooxidans

Bobadilla-Fazzini,

Poblete-Castro

2023

Front. Bioeng. Biotechnol.

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The presence of sulfur impurities in complex iron ores represents a significant challenge for the iron mining and steel-making industries as their removal often necessitates the use of hazardous chemicals and energy-intensive processes. Here, we examined the microbial and mineralogical composition of both primary and secondary iron concentrates, identifying the presence of Sulfobacillus spp. and Leptospirillum spp., while sulfur-oxidizing bacteria were absent. We also observed that these concentrates displayed up to 85% exposed pyrrhotite. These observations led us to explore the capacity of Acidithiobacillus thiooxidans to remove pyrrhotite-sulfur impurities from iron concentrates. Employing stirred tank bioreactors operating at 30°C and inoculated with 5·106 (At. thiooxidans cells mL-1), we achieved 45.6% sulfur removal over 16 days. Then, we evaluated packed leaching columns operated at 30°C, where the At. thiooxidans enriched system reached 43.5% desulfurization over 60 days. Remarkably, sulfur removal increased to 80% within 21 days under potassium limitation. We then compared the At. thiooxidans-mediated desulfurization process, with and without air supply, under potassium limitation, varying the initial biomass concentration in 1-m columns. Aerated systems facilitated approximately 70% sulfur removal across the entire column with minimal iron loss. In contrast, non-aerated leaching columns achieved desulfurization levels of only 6% and 26% in the lower and middle sections of the column, respectively. Collectively, we have developed an efficient, scalable biological sulfur-removal technology for processing complex iron ores, aligning with the burgeoning demand for sustainable practices in the mining industry.

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Section: Discussionmentioning

confidence: 99%

Establishing a green biodesulfurization process for iron ore concentrates in stirred tank and leaching column bioreactors using Acidithiobacillus thiooxidans

Bobadilla-Fazzini,

Poblete-Castro

2023

Front. Bioeng. Biotechnol.

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“…However, due to the long period of bioleaching process and the huge volume of heaps, airflow is difficult to infiltrate the heap by natural convection [10]. This will seriously inhibit the reproduction of acidophilic and oxygen-consuming autotrophic microorganisms and ore leaching.…”

Section: Introductionmentioning

confidence: 99%

Aeration Accelerates the Microbial Leaching of Low-Grade Copper Sulfide Ores

Huang,

Li,

Zhang

et al. 2023

Preprint

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The airflow carried by artificial aeration provides oxidant O2 for microbial growth and mineral dissolution in heap bioleaching. To investigate the effect of forced aeration rate on bioleaching of low-grade copper sulfide ores, column bioleaching experiments with six columns were conducted in the aeration range of 0~150 L/h at 30~45 ℃. The results showed that when the aeration rate was higher than 95 L/h, the proportions of heap settlement and fine particles mass were much greater than that without aeration. The final total Fe concentration and bacterial cell numbers in pregnant leach solution increased with the increase of aeration rate.The final concentrations of Cu2 + in the mother liquor under aeration conditions of 60-150 L / h were 1.411, 1.432, 1.498, 1.491 and 1.583 g / L, respectively, which were higher than 1.345 g / L under non-aeration conditions. When the aeration rate was 150 L / h, the final Cu leaching rate was 80.1 %, which was 11.4 % higher than that without aeration ( 68.7 % ). Furthermore, in the early stage of leaching, copper leaching rate with 95 L/h aeration rate remained the highest. 结论Artificial aeration accelerates the bioleaching of low-grade copper sulfide ores by improving porosity structure, temperature range of bacterial activity and microbial catalyzed dissolution of targeted minerals.

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“…Therefore, it is a very effective method to prevent coal from reaching the critical temperature of spontaneous combustion through inhibitors. However, effective efficiency and reuse rate of traditional inhibitors are low, and the stability is poor. , Because of their good properties, such as high energy storage density and high capacity heat storage at almost constant temperature, , phase change materials (PCMs) have been widely used in building energy saving, food storage, greenhouse energy saving, and solar energy storage industries. − In order to overcome the changes in the intensity of sunlight at different times of day and night, the application of PCMs in solar integration and Trombe walls emerges . When selecting the appropriate PCM for the required application field, it is important to consider the phase transition temperature range that can meet the requirements.…”

Section: Introductionmentioning

confidence: 99%

Development of Composite Phase Change Material for Preventing Spontaneous Combustion of Coal and Its Thermo-Physical Properties

Tang

Chen

et al. 2022

Energy Fuels

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In order to further study the application of phase change materials in inhibitors to prevent spontaneous combustion of coal, AlNH4(SO4)2·12H2O and MgSO4·7H2O were used as raw materials to obtain binary eutectic by melt impregnation. The phase transition temperature of the new material is around 70 °C, which is in the critical temperature range of the coal oxidation process. The material melts and absorbs the heat of coal during the phase change, so that the temperature of the coal is lower than the critical temperature. At the same time, it penetrates into the pores of the coal to isolate oxygen and achieves the effect of blocking the self-heating process of coal oxidation. The experimental results point out that as the proportion of AlNH4(SO4)2·12H2O in the binary eutectic increases, the better the material fusion becomes. The phase transition temperature decreases sharply at first and then slowly increases and stabilizes. The latent heat of change fluctuates back and forth between 260 and 290 J/g and then obviously decreases. Weight loss is basically between 20 and 40%. The optimization experiment pointed out that the best result is when the content of AlNH4(SO4)2·12H2O is 57.6%. Under this amount, the latent heat of phase transition is 298.67 J/g, the phase transition temperature is 65.88 °C, the weight loss rate is 27.2%, and the undercooling degree is 7.1 °C.

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Effects of forced aeration on community dynamics of free and attached bacteria in copper sulphide ore bioleaching

Cited by 21 publications

References 29 publications

Establishing a green biodesulfurization process for iron ore concentrates in stirred tank and leaching column bioreactors using Acidithiobacillus thiooxidans

Establishing a green biodesulfurization process for iron ore concentrates in stirred tank and leaching column bioreactors using Acidithiobacillus thiooxidans

Aeration Accelerates the Microbial Leaching of Low-Grade Copper Sulfide Ores

Development of Composite Phase Change Material for Preventing Spontaneous Combustion of Coal and Its Thermo-Physical Properties

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