As a consequence of historic tin-mining activities up until late 1980s, several mining disposals exist in the German Erzgebirge (Ore Mountains). These disposals still contain substantial amounts of cassiterite (mainly as ultrafine particles) resulting either from de-sliming steps or from tailings of separation methods, which were not sensitive enough for fine particles. Based on industrial demands, there is a considerable interest to reprocess these disposals using beneficiation methods for ultrafine particles.In this paper we report on the reprocessing of material from one exemplary heap applying oil-assisted flotation methods (oil agglomeration flotation and two-liquid flotation). Isooctane as a non-polar oil was used to promote the collection of cassiterite either by selective aggregation or as carriers. Recovery and product quality are investigated with different process parameters: various collectors (e.g. sulphosuccinamates and phosphonic acids), particle sizes, oil dosage, oil/pulp agitation time and pulp density. Furthermore, a comparison between these results with conventional flotation tests without using oil as process aid is presented.
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