Possibilities to use industrial oxidic by-products as neutralising agent in bioleaching
2009 (English)In: IBS 2009 Abstract Book / [ed] Edgardo R. Donati; Marisa R. Viera; Eduardo L. Tavani; Maria A. Giaveno; Teresa L. Lavalle; Patricia A. Chiacchiarini, 2009, 139- p.Conference paper, Meeting abstract (Other academic)
The present study aims for the possibilities to use industrial oxidic by-products as neutralising agent in biooxidation. Neutralising agent is required to neutralise the acid produced during the biooxidation. Possibilities to replace conventionally used limestone with by-products based on their neutralising capacities and possible harmful effects were investigated. Ten different by-products were used with reference to slaked lime. Batch bioleaching of a pyrite concentrate were conducted in 1-L reactor using mesophilic microorganisms at 35º C. The by-products used were different types of steel slags, ashes, dust and mesalime. The neutralising capacities of the by-products were determined by the amount of by-products needed for neutralisation during biooxidation. The amount of steel slags, EAF dust, Mesalime and Bioash needed for neutralisation ranged from 16-37 g, Waste ash and Coal & Tyres ash needed 81 g and 57 g, respectively, while the slaked lime reference needed 22 g. The experiment with Waste ash gave the lowest pyrite oxidation of 59 %, while the other by-products had similar or better pyrite oxidation compared to slaked lime, ranging from 69-80%. Fluoride, chromium and vanadium were potentially toxic elements present in some of the by-products, but had no negative impact on the bacterial activity. A chloride concentration of 11%, eventually together with other potentially toxic elements, in the Waste ash caused a negative effect, observed by low redox potential and pyrite oxidation. Stainless steel slags should be avoided for environmental reasons due to the presence of chromium. High content of zinc in EAF dust would enrich the zinc tenor, if used as neutralising agent in bioleaching of zinc sulphides, but chloride should be removed before its use. Replacement of limestone with by-products in biooxidation processes could save operating costs without negative impact on the biooxidation efficiency and conserve virgin limestone deposits.
Place, publisher, year, edition, pages
2009. 139- p.
Research subject Process Metallurgy
IdentifiersURN: urn:nbn:se:ltu:diva-29457Local ID: 2f229d20-c3ec-11df-a707-000ea68e967bOAI: oai:DiVA.org:ltu-29457DiVA: diva2:1002681
International Biohydrometallurgy Symposium : 13/09/2009 - 17/09/2009
Godkänd; 2009; 20100919 (sekgah)2016-09-302016-09-30Bibliographically approved