Use of Flotation in the Removal of Heavy Metals from Contaminated Soils
This paper presents the preliminary results of a research programme conducted to assess the feasibility of a flotation technique in the remediation of soils severely affected by heavy metal contamination.The use of flotation in soil remediation is a recent practice. The main difficulties are given by the variety and peculiarity of the heavy metal containing species,and also by the grain size. Most of the studies reported in the literature concern the use of conventional collectors,such as xanthates,after a preliminary chemical modification of the metal bearing species through sulphidization.On the basis of the minera-petrographic characterization and of speciation,some classes of reagents have been selected,capable of acting both on metal-bearing species and all metallic cations to be separated.The design of the synthetic molecules has been based on the coordinative properties of the metallic centres and functionalized in order to act as collectors for a wide range of metals independently on their surrounding atoms.In laboratory experiments a sample of stream sediment has been utilized,whose contamination is caused by the runoff from Sardinia mine waste dumps and overflow from the settling ponds. The material showed contamination mainly from Zn,Pb and Cu and to a lesser extent from Cr,Ni,Cd,and Sb associated in mixed particles of Fe and Mn.Flotation tests on a laboratory scale have been performed on grain sizes less than 355 μm in laboratory cell Minerais & Metaux.The effects of the structure of collectors (functional group,chain configuration) as well as of the principal flotation parameters (such as pH,concentration of reagent) on the grade and recovery of heavy metals in the concentrate and in the tailings (remediated soil) have been investigated.The results of the laboratory tests substantially confirm the theoretical premises,and the most effecive reagents found belong to the classes ATE MBT,MBO,fat acids and phosphates.
Contaminated soils Heavy metals Removal Flotation
G.Belardi M.Barbaro M.Ciriachi B.Passariello L.Passeri
Istituto di Geologia Ambientale e Geoingegneria,Italy
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
4053-4065
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）