Batch comminution

In batch comminution, the summation term in equation (4.11) is zero because there are no flows into or out of the mill. Therefore the population balance on a discrete mass basis is simplified to... 

The aim of the paper was to describe the process of grinding of raw materials used in the industrial-scale production of ceramic tiles, by applying the theory of statistical moments. Grinding was performed in industrial ball mills in ceramic tile factories Ceramika Paradyz Ltd. and Opoczno S.A. The ball mills operated in a batch mode. A mixture of feldspars and clay was comminuted. Its composition and fractions depended on the conditions that should be satisfied by raw materials for the production of wall tiles (monoporosis and stoneware) and terracotta. The ground material was subjected to a particle size analysis. Results of the analysis were used in the calculation of relationships applied in the theory of statistical moments. The main parameters, i.e. zero moment of the first order and central moments of the third and fourth order were determined. The values of central moments were used in the calculation of skewness and flatness coefficients. Additionally, changes of mean particle size in time were determined. 

To use natural minerals it is necessary to grind them down to a desired particle size distribution. Grinding can be performed with the minerals dry or slurried in liquid. In most laboratories, this process is performed in a batch jar mill while on an industrial scale, continuous comminution equipment is used in conjunction with size classification equipment to recycle the coarse material. Figure 4.1 shows a typical comminution circuit with classification and recycle steps, as well as separation of the mineral from the conve3ring fluid. 

Dea lomeration can take place by two methods comminution and ultrasonification. Comminution is the subject of Chapter 4, so it will not be discussed in detail here. In the comminution of aggregates, the popvdation balance can be used to predict the size distribution as a function of time in a batch mill or as a function of mean residence time in a continuous mill. Aggregates have the same type of birth and death fvmctions for particle breakage as polycrystalline particles but the rate constants are much hi er and the size selectivities for aggregates are different than those for the comminution of crystalline materials. The... 

This attractive technique was first tested to micronize explosives (18,72-74). Mechanical methods such as milling generate high local temperatures, and therefore are useless in this particular case the use of SCCO2 as an antisolvent allowed comminution to proceed at mild temperatures. As already noted, the GAS process is a batch technique, which entails the gradual introduction of a compressed gas into a liquid solution of the solute of interest in a primary organic solvent. This method is based on the ability of liquids to... 

Master batches are always passed to a compounding unit and then granulated or comminuted. The granulated mixtures (obtained by dilution of master... 

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