SIXTH INTERNATIONAL CONFERENCE
«Materials and Coatings for Extreme Performances: Investigations, Applications, Ecologically Safe Technologies for Their Production and Utilization»
September 20-24, 2010 Ponizovka, Crimea, Ukraine
RECLAMATION OF INDUSTRIAL WASTE WITH CONTENT OF MANGANESE BY METHOD OF BACTERIAL LEACHING
Sakhvadze D.V., Sakhvadze L.I., Jandieri G.V., Rapava A.V., Gigauri R.M., Shukin B.A., Tavadze G.F.
Ferdinand Tavadze Institute of Metallurgy and Materials Science,
15, av. Al. Kazbegi, Tbilisi, 0160, Georgia
Production of manganese in the mining and metallurgical industry is related to the loss of more than 50% of mineral resources as industrial waste. This gives rise to the deterioration of industrial and economic indices as well as to a considerable environmental pollution. Especially problematic is the matter of reclamation of dust, slurry and slag formed due to the metallurgical refining process of manganese ore [1,2].
Study of manganese transformation and migration processes under the influence of microorganisms has for an object the solution of practical tasks for the development of efficiet technology of manganese leaching from poor ores and waste of the mining and metallurgical refining process (dust, slarry, slag etc) [3].
But the problem of processing of the complicated complex manganese-containing Industrial waste is for the present on the stage of development.
The object of investigation is manganese-containing industrial waste representing a fine disperse powered mass released as a result of gas dry cleaning from the reactivity zone of furnace (Fig.1,a).
Today in some countries heterotrophic bacteria are used for manganese leaching and as an energetical material – difficult-to-obtain, expensive organic compounds. The worked out technology excludes the use of organic compounds; it is based upon autotrophic bacteria oxidizing the sulphide minerals up to the sulphate of lower iron oxide.
For the growth of microorganisms the ferrous iron, sulphur and sulphide mineral are used as energetical sources. The optimum temperature of growth of microorganisms makes up 28oC when pH of medium is 2,3 – 2,8.
Strains have been extracted from geothermal waters of the city of Tbilisi. The strains Th. Ferrooxidans extracted from the source N5 showed a great activity.
Sulphuric acid and products of metabolism of bacteria – oxalic acid are formed during the process of leaching. They dissolve manganese oxides. The presence of sulphuric acid in the solution ensures the dissolution of manganese carbonates.
After filtering out the products of leaching we get the solution of manganese sulphate in which the concentration of manganese makes up 45 gr/l. These solutions are suitable for the electrolythic extraction of ferrous manganese and electrolythic dioxide of manganese.
It is also possible to get the monohydrate of manganese sulphate from the solution (Fig.1,b)
Fig.1. a) initial material (dust); b) manganese sulphate
As a result of purely biochemical activity of bacteria, the extraction of manganese in 10 twenty-four hours reaches 94% and in 12 twenty-four hours – 98%.
References:
1. Karavaiko G.I., Kuznetsov S.I., Golomzik A.I. The role of microorganisms in leaching of metals from ores, M. Nauka, 1972. (in Russia)
2. Polkin S.I., Adamov E.V., Panin V.V., Technology of bacterial leaching of non-ferrous and rare-earth metals, M. Nedra, 1982. (in Russia)
3. Sakhvadze D.V., Sakhvadze L.I., Jandieri G.V., Tavadze G.F., Rapava A.V. Bacterial leaching of manganese from technogennic waste in the mining and metallurgical industry of Georgia, Works of the Institute of Microbiology, Academy of Sciences of Azerbaidjan, Baku, 2009, pp. 299-303. (in Russia)