Inhibition of acid generation from sulphidic wastes by the addition of small amounts of limestone

Mylona, E; Xenidis, A; Paspaliaris, I

dc.contributor.author	Mylona, E	en
dc.contributor.author	Xenidis, A	en
dc.contributor.author	Paspaliaris, I	en
dc.date.accessioned	2014-03-01T01:15:39Z
dc.date.available	2014-03-01T01:15:39Z
dc.date.issued	2000	en
dc.identifier.issn	0892-6875	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/13653
dc.subject	acid rock drainage	en
dc.subject	oxidation	en
dc.subject	environmental	en
dc.subject	reclamation	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.classification	Mineralogy	en
dc.subject.classification	Mining & Mineral Processing	en
dc.subject.other	CARBONATE-BUFFERED SOLUTION	en
dc.subject.other	MINE-DRAINAGE	en
dc.subject.other	PYRITE OXIDATION	en
dc.subject.other	TAILINGS	en
dc.title	Inhibition of acid generation from sulphidic wastes by the addition of small amounts of limestone	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0892-6875(00)00099-6	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0892-6875(00)00099-6	en
heal.language	English	en
heal.publicationDate	2000	en
heal.abstract	Limestone addition is a commonly applied technique to prevent acid generation from sulphidic wastes containing 1-10% S. In the present paper, the effectiveness of small amounts, lower than the stoichiometric requirement, of this alkaline additive in inhibiting acid generation from a pyrite concentrate material is studied. Long term laboratory column tests were conducted on a partially oxidised pyrite concentrate, where limestone was added by thoroughly mixing. The amount of alkaline additive ranged front 6.4 to 29% wt. corresponding to 5-30% of the stoichiometric quantity. The performance of the pyrite-limestone mixtures was evaluated by monitoring the drainage quality of the columns, Furthermore, a detailed geochemical characterisation of the column solid residues was performed after a monitoring period of 270 days. The effect of secondary oxidation-neutralisation products on the hydraulic conductivity of material was also examined. Dissolution of previously formed oxidation products occurred in the control column during the monitoring period, resulting in the release of a significant amount of Fe, Zn, Mn, Cd, As and SO4 and to a lesser extent Pb. However, due to the presence of secondary products, further oxidation of pyrite particles was delayed, The experimental results slowed that homogeneous mixing of pyrite with limestone amounting to only a fraction of the contained acidity inhibited the generation of acidic drainage and significantly reduced the dissolved amount of metals and sulphates for a test period of 270 days. Under the alkaline conditions prevailing in the limestone amended columns, secondary precipitation of ferric hydroxides and gypsum occurred. A ten-fold decrease of hydraulic conductivity was observed for the material amended with 207 kg CaCO3/t, corresponding to 15% of the contained acidity. (C) 2000 Elsevier Science Ltd. All rights reserved.	en
heal.publisher	PERGAMON-ELSEVIER SCIENCE LTD	en
heal.journalName	MINERALS ENGINEERING	en
dc.identifier.doi	10.1016/S0892-6875(00)00099-6	en
dc.identifier.isi	ISI:000088842000015	en
dc.identifier.volume	13	en
dc.identifier.issue	10-11	en
dc.identifier.spage	1161	en
dc.identifier.epage	1175	en