Hydrometallurgical procedure for the production of ferric-sulfate from fayalite slag
Inventors
Roman Espinoza, Enrique Anselmo • JORDAN GUTIERREZ HECTOR DARIO, null • Jordan Gutierrez, Héctor Dario • Padilla Iglesias, Leandro Mauricio • Morales Cerda, Pedro Antonio • Badilla Ohlbaum, Ricardo
Assignees
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Publication Number
US-8470569-B2
Publication Date
2013-06-25
Expiration Date
Abstract
The present invention corresponds to a commercial production process of ferric sulfate whose plant can be installed scaled to the requirements of the process of application of the bio-produced ferric solution based on fayalite slag generated in copper smelting plants. No previous process has established as its method of industrial application the use of these smelter slags in the bio-production of ferric sulfate solutions at concentrations above 20 g/L, including a stage of acid-slag leaching in dynamic heaps with control of generated silica and subsequent precipitation of colloidal silica and other impurities in a stirred reactor in the invented process. The ferrous solution free of colloidal silica and other impurities is subjected to a process of bio-oxidization of the clean ferrous solution by microorganisms adapted to these metallurgical solutions.
Core Innovation
The described invention relates to a continuous hydrometallurgical procedure for producing ferric sulfate solutions having an iron concentration greater than 20 g/L while maintaining silicon and other impurities at less than 1 g/L. The process is carried out in continuous mode in three sequential steps, starting by acid leaching fayalite slag in a leaching heap, where the fayalite slag is granulated and classified with a particle diameter greater than 0.1 cm.
After leaching, percolated leaching liquid is collected and silicon, aluminum and other impurities are removed from the percolated leaching liquid. The silicon removal is performed either through thermal coagulation and precipitation of colloidal silica or alternatively through neutralization with lime slurry, forming a ferrous solution comprising less than 1 g/L of silicon.
Finally, the ferrous solution is bio-oxidized in a bioreactor to form the ferric sulfate solution with an iron concentration greater than 20 g/L. The document further characterizes embodiments using an air-lift bioreactor with immobilized biomass and iron-oxidizing microorganisms, producing high ferric-ion concentrations with low impurity content under controlled conditions.
Claims Coverage
The claims cover one main independent continuous three-step hydrometallurgical procedure, with dependent refinements specifying the leaching, impurity removal, and biological oxidation features. Across the claims, the inventive coverage centers on acid leaching of fayalite slag, removal of silicon, aluminum and other impurities to less than 1 g/L silicon, and bio-oxidation to obtain ferric sulfate with iron concentration greater than 20 g/L.
Continuous three-step hydrometallurgical procedure for ferric sulfate with low silicon
A hydrometallurgical procedure for producing ferric sulfate solutions comprising an iron concentration greater than 20 g/L, and less than 1 g/L of silicon and other impurities, carried out in continuous mode in three sequential steps comprising acid leaching fayalite slag in a leaching heap, removing silicon, aluminum and other impurities from the percolated leaching liquid through thermal coagulation and precipitation of colloidal silica or alternatively neutralization with lime slurry to form a ferrous solution comprising less than 1 g/L of silicon, and bio-oxidizing the ferrous solution in a bioreactor to form the ferric sulfate solution comprising an iron concentration greater than 20 g/L.
Granulated and classified fayalite slag for heap acid leaching
Acid leaching fayalite slag in a leaching heap, wherein the fayalite slag comprises fayalite slag from an electric furnace for reductive slag cleaning and is granulated and classified 100% with a particle diameter greater than 0.1 cm.
Thermal coagulation and precipitation of colloidal silica or lime slurry neutralization
Removing silicon, aluminum and other impurities in the percolated leaching liquid through thermal coagulation and precipitation of colloidal silica, or alternatively, neutralization with lime slurry, to form a ferrous solution comprising less than 1 g/L of silicon.
Bio-oxidizing in a bioreactor to form ferric sulfate
Bio-oxidizing the ferrous solution in a bioreactor to form the ferric sulfate solution comprising an iron concentration greater than 20 g/L.
Air-lift bioreactor with immobilized biomass
Operating the bio-oxidizing step in an air-lift bioreactor with immobilized biomass and iron-oxidizing microorganisms to produce a final ferric sulfate solution having ferric-ion concentration above 50 g/L and low impurity content (<1 g/L).
The claims define a continuous hydrometallurgical sequence in which granulated fayalite slag is acid leached, impurities are removed to reduce silicon below 1 g/L, and the resulting ferrous solution is bio-oxidized in a bioreactor to form ferric sulfate with iron concentration greater than 20 g/L, including embodiments using an air-lift bioreactor with immobilized biomass and iron-oxidizing microorganisms.
Stated Advantages
Produces ferric sulfate solutions comprising an iron concentration greater than 20 g/L.
Maintains silicon and other impurities at less than 1 g/L.
Provides continuous operation in three sequential steps.
Enables ferrous solutions with less than 1 g/L of silicon after silicon and impurity removal.
Produces final ferric sulfate solutions with ferric-ion concentration above 50 g/L and low impurity content (<1 g/L) in specified air-lift bioreactor embodiments.
Achieves productivity over 4.2 Kg Ferric h^-1 m^-3 in specified air-lift bioreactor embodiments.
Documented Applications
Producing ferric sulfate solutions from fayalite slag waste from copper smelting/copper smelting plants, using the fayalite slag from an electric furnace for reductive slag cleaning.
Bio-oxidizing a purified ferrous solution in a bioreactor to form the ferric sulfate solution.
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