Use of some isolated fungi in biological Leaching of Aluminum from low grade bauxite

In this investigation the biological leaching of aluminum by isolated fungi from low grade bauxite

Kinetic comparison of biological and conventional flotation of coal

Froth flotation is commonly used in coal processing to selectively recover the organic material (coal) from inorganic waste material. Tabas coal, located in east Iran, contains fine disseminated pyrite which is floated with coal during flotation, and hence decreasing the quality of the final concentrate. Reagents, such as sodium cyanide, are typically added to depress pyrite. Due to the toxicity of cyanide, alternative strategies for depressing pyrite flotation are being investigated. In this paper the metallurgical performance of Tabas coal treated with sodium cyanide is compared to that of Tabas coal which has undergone bacterial treatment using Acidithiobacillus ferrooxidans. Results indicate that bacterial treatment decreases the flotation rate of pyrite and improves the selectivity between coal and gangue. The possibility of using bacteria in place of toxic chemicals such as cyanide has significant environmental benefit

Aluminum solubilization from red mud by some indigenous fungi in Iran

ABSTRACT Objective: The biological leaching of aluminum (Al) by fungi isolated from red mud, the main waste product of the alkaline extraction of Al from bauxite was studied. Methodology and results: Biological leaching experiments were carried out using indigenous fungal isolates, Aspergillus niger and Penicillium notatum. Sabouroud Dextrose Chloramphenicol Agar (SDA) was used as medium for culturing the selected fungi. All microorganisms were tested for acid-production and leaching capabilities of aluminum from red mud. Leaching tests were performed in 250 ml Erlenmeyer flasks at 28°C and 150 rpm under aseptic conditions. Heating of red mud and its impact on the leaching process was also investigated. Indigenous specimen fungi were the most efficient with 2082 mg of Al2O3/l solubilized at 15% pulp density of red mud. The metal content of leaching solution was determined using wet chemical and atomic absorption spectrophotometer. Conclusion and application of findings: Significant amounts of Aluminum and Titanium were obtained through bioleaching processes thus demonstrating that some Iranian fungal isolates have potential application in extraction of metals. Further research could lead to discovery of more efficient isolates and improvement in efficiency of the bioleaching technology

Solvent refining of silicon using nickel as impurity getter

The effectiveness of Ni as an impurity trapper in refining of silicon has been studied. Metallurgical grade silicon was alloyed with Ni and the molten alloy solidified by slow cooling at various cooling rates. Silicon dendrites grown during solidification of the alloy were subsequently recovered from the matrix by employing a heavy media separation technique. The process efficiency was studied in terms of the effectiveness of the physical separation technique and the degree of purification of Si.The authors gratefully acknowledge the funding support of this research project by the Natural Sciences and Engineering Research Council of Canada (NSERC) and the ARISE Technologies Corporation

Use of some isolated fungi in biological Leaching of Aluminum from low grade bauxite

In this investigation the biological leaching of aluminum by isolated fungi from low grade bauxite (<50 Al2O3.) was studied. X-ray diffraction investigation indicated that silicate and aluminosillicate minerals were major mineral composition. Wet chemical and electron disperse X-ray analysis showed the presence of aluminum, iron, silica and titanium. Biological leaching tests were carried out using indigenous specimen fungi, Aspergillus niger and Penicillium notatum. Savored dextrose chloramphenicol agar (SDA) was used as medium for the selected fungi. All microorganisms were tested for acid-production and leaching capabilities of aluminum from low grad bauxite. Leaching experiments were performed in 250-ml Erlenmeyer flasks at 28°C and at 150 rpm agitation under aseptic conditions. Pry heating of bauxite and its effect on leaching process was studied. Indigenous specimen fungi were the most efficient of the fungal cultures; 7080 mg of Al 2O3/l was solubilized at 15 pulp density of bauxite. The metal content of leaching solution was determined by using wet chemical and atomic absorption spectrophotometer. © 2007 Academic Journals

Application of Acidithiobacillus Ferrooxidans in Coal Flotation

Bioflotation is a potential method for removing pyritic sulphur from coal. Sodium cyanide is a well-known depressant for pyrite in flotation of sulphide minerals; however, for coal this reagent is unacceptable from the environmental point of view. This study investigates an alternate to sodium cyanide; Acidithiobacillus Ferrooxidans, a nonharmful bacterial reagent as a pyrite depressant. The flotation behavior of pyrite and other gangue particles using the sodium cyanide and the Ferrooxidans is compared by applying the general first-order flotation model. The kinetic parameters extracted from the model demonstrated that the modified flotation rate of pyrite was reduced, and the selectivity between coal and gangue was improved using the bacteria. These results indicate that Acidithiobacillus Ferrooxidans has potential in removing pyritic sulfur from coal. Copyrigh

Biological leaching of aluminum from low grade bauxite by some isolated fungi

In this investigation the biological leaching of aluminum by isolated fungi from low grade bauxite (<50 Al2O3.) was studied. X-ray diffraction investigation indicated that silicate and aluminosllicate minerals were major mineral composition. Wet chemical and electron disperse X-ray analysis showed the presence of aluminum, iron, silica and titanium. Biological leaching tests were carried out using indigenous specimen fungi, Aspergillus niger, Penicillium notatum. Savored Dextrose chloramphenicol Agar (SDA) was used as medium for the selected fungi. All microorganisms were tested for acid-production and leaching capabilities of aluminum from low grad bauxite. Leaching experiments were performed in 250-ml Erlenmeyer flasks at 28°C and at 150 rpm agitation under aseptic conditions. Pry heating of bauxite and its effect on leaching process was studied. Indigenous specimen fungi were the most efficient of the fungal cultures; 7080 mg of Al2O3/l was solubilized at 15 pulp density of bauxite. The metal content of leaching solution was determined by using wet chemical and atomic absorption spectrophotometer