# Dissolution of particles of pyrite mineral by direct attachment of Thiobacillus ferrooxidans

Shrihari, * and Modak, Jayant M and Kumar, R and Gandhi, KS (1995) Dissolution of particles of pyrite mineral by direct attachment of Thiobacillus ferrooxidans. In: Hydrometallurgy, 38 (2). pp. 175-187.

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## Abstract

Shake flask experimentson the leaching of particles of pyrite mineral with Thiobacillusferrooxidans indicate that, under conditions of large particle sizes and high pulp density, the dissolution occurs primarily through direct attachment of the micro-organism on the mineral surface. Even though both $Fe^{2+}$ and the cells are present in the aqueous phase, there is negligible oxidation of $Fe^{2+}$ to $Fe^{3+}$ at 20% pulp density. The main products of the reaction are $FeSO_4$, and $H_2S0_4$. For particle sizes in the range 150-2830 \mu m, the rate of leaching is found to increase as the particle size increases, in spite of the lower surface area available. These unexpected results have been explained by assuming that the bacteria preferentially attach to specific sites, which are formedduring grinding. A model incorporating the number of attachment sites and leaching at these sites is proposed to explain the experimental results.

Item Type: Journal Article Copyright of this article belongs to Elsevier. Division of Mechanical Sciences > Chemical Engineering RM Shivakumara 26 Jun 2008 19 Sep 2010 04:46 http://eprints.iisc.ac.in/id/eprint/14573