ABSTRACT
All of the nonselective operations performed on a lot of material, or on the successive samples are referred to as “preparation stages.” These preparation stages are necessary to convey the increments and samples to a predetermined location and to modify them into an appropriate form for the ultimate analytical stage. A large number of articles and books written on sampling confuse selective operations (i.e., sampling in a proper sense) with nonselective operations (i.e., preparation stages). It should be emphasized that unless this differentiation is clearly made, and accepted, it is impossible to conduct a logical analysis of all the errors involved in the Overall Estimation Error OEE. At this stage the reader should again refer to Figures 4.1 and 4.2 in Chapter 4. These preparation stages can be classified into various categories such as:
Transfer of the increment from the cutter to a conveying system, which may or may not be a continuous operation.
Transfer from the conveying system to the next sampling or preparation stage.
Comminution stages, whose functions are to diminish the particle size d, and to increase the number of particles (e.g., crushing, grinding, and pulverizing).
Wet or dry screening, often in connection with a comminution.
Drying of solids loaded with various amounts of moisture. This operation is often necessary to minimize clogging of sticky materials in the sampling circuit.
Filtration of pulps to separate the solid phase from the liquid phase, and so on.
Homogenizing processes.
