Mineral processing unit operations

This section on flowsheets basically aims to provide some illustrative examples of the use of the various mineral processing unit operations that have been described. A general flowsheet involving almost all the unit operations pertinent to mineral processing is shown in Figure 2.32. The others refer specifically to beach sands, lead-zinc concentration, molybdenum, and the rare earths. 

This review comprises most of the presentations given at the RSC Industrial Affairs Division Speciality Chemicals Sector conference titled Speciality Chemicals in Mineral Processing held in Bath, UK in 2001. The papers presented here are not intended to represent a comprehensive review of the use of speciality chemicals in mineral processing but rather the intention is to highlight a significant advance in chemical use in each of a number of different mineral process unit operations. The book is divided into three sections (i) dispersion and flocculation, (ii) selective processing and (iii) microbiological control. Within each of these areas papers are presented that cover some of the most important recent research and developments from both academia and industry. 

Processing costs include those for size reduction, size classification, minerals concentration and separations, soHd—Hquid separation (dewatering), materials handling and transportation, and tailings disposal. Size reduction, one of the most expensive unit operations in minerals processing, could account for as much as 50% of the total energy consumed. This cost varies considerably from deposit to deposit and quite often from one area of a deposit to another. Ore bodies are extremely heterogeneous and the associated minerals Hberation, complex. 

Mineral processing spent materials. Mineral processing generates spent materials that may exhibit hazardous waste characteristics. Common industry practice is to recycle these mineral processing wastes back into the processing operations to recover mineral value. U.S. EPA created a conditional exclusion from the definition of solid waste for these spent materials when recycled in the mineral processing industry, provided the materials are stored in certain types of units and are not accumulated speculatively. 

Surface or Interfacial Properties which are Considered Directly Responsible for Performance of Various Unit Operations in Mineral Processing... 

Coal beneficiation involves a series of steps to separate the mineral matter from the combustible portion of the coal. Current coal characterization for beneficiation is usually limited to measurements of the particle specific gravity distribution (washability). It is further assumed that the properties of the coal feed stream and related mineral matter remain constant during the separation or cleaning process, but the compositions of the streams do change. These changes are important in understanding the lack of expected separations. The effects of specific mineral constituents on different unit operations are described. Better measurement and analytical systems will permit improved control of the processes and better separations. 

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