Using Humidity Ceils Tests to Evaluate an ARD Minimization Approach in Santa Catarina Coal Field, Brazil

摘要

The aim of this work was to use humidity cells tests to evaluate the effectiveness of an ARD minimisation approach for coal discard from the Santa Catarina coal field, Brazil. Coal waste sample was obtained from a typical beneficiation plant and separated into three density fractions, using a ferrosilicon medium. Further characterisation of these density fractions indicated that the low (<2.2 g/cm~3) and high (> 2.7 g/cm~3) density fractions are potentially suitable for energy and sulfuric acid production respectively. The waste fraction of intermediate density (2.2-2.7 g/cm~3) had a reduced sulphide sulfur content, and it was postulated that it may be suitable for land disposal with minimum risk to the surrounding environment. This hypothesis was tested using laboratory-scale static and humidity cell tests. The results of these tests indicated that, whilst the intermediate density waste fraction remained acid generating, the release of metals, salts and acidity into solution was considerably lower than that obtained for the discards before density separation. This has important implication in terms of reagent requirements and sludge generation during subsequent ARD treatment.