Analysis of Dust Emission for Selected Crushers

"The paper focuses on problems of atmospheric pollution by the dusts, produced during the course of crushing and grinding processes, and the main objective of investigative programme is an assessment of emission of particulate pollutants for following crushing devices operated in plant scale: impactors, cone and jaw crushers. All crushers operate in aggregate production plants in Poland. In the first stage of investigations there were determined dust emission levels and supporting characteristics for all crushers under investigation. Then there were introduced indices that allow for comparative analysis in terms of dust emission, for devices with different energy consumptions and comminution ratio. It appeared that crushers with high the overall dust emission do not always achieved unfavorable dust emission per comminution ratio or energy consumption. The introduced indices proved their usefulness, because they helped to carry out a comparative analysis among crushers, operating under different technological conditions. It is also easier to assess environmental impact of individual crushing devices, under analysis. Results of investigations also show that environmental impact of different types of crushers is diverse and it is difficult to compare dust emissions of various types of crushers without taking into account technological aspects (like throughput, comminution ratio, energy consumption, and others) of their operations.INTRODUCTION Mineral processing of raw material is a complex process, involving in general operations of size reductions and separation. Depending on the type of specific raw material, the technological circuit may include operations of comminution and size classification. This is a typical circuit for aggregate production. In ore treatment industry the process in much more complicated and include also a metallurgical treatment of ore concentrate – the final product from processing plant stage.In general, regardless the type of raw material, operations of size reduction are present in each technological circuit of mineral processing. Operations of crushing and grinding are an integral part of processing technology, because they play a crucial role in effective treatment of mineral raw materials (Gawenda 2013). Their duty is to liberate the useful minerals from the gangue in ore treatment industry, or to produce the material with the required particle size in case of aggregate processing. Crushing and grinding operations are of a high negative impact on environment and humans. They consume great amounts of energy, what indirectly contributes to higher emission of carbon dioxide CO2. Apart from energy, crushing and grinding device consume significant amount of steel and other metals and alloys due to high wear of working parts and grinding media. This is also of negative environmental impact due to emissions of additional amounts of CO2 in production of steel and other metals required as spare parts for comminution devices."