Re-selection of the basic principles (3)

The stratification of many light and heavy minerals with large difference in particle size has been examined and found to be close to the above relationship.
C. The stratification of potential energy FW Meyer (Yayer 1947), through the analysis of the jigging bed, the potential energy of the layer after stratification is lower than the potential energy before stratification (here, the height of the bed is high) The product of its weight). Based on the general rule that the free energy in the limited system of nature has a change from high to low, as long as the bed particles have the possibility of relative transfer, the heavy minerals entering the bottom layer should be able to proceed spontaneously. That is, stratification is a process in which the potential energy is reduced by redistribution of particles. Of course, there should be no flow of water during this process, ie stratification should be carried out under "static" conditions.
Referring to Fig. 4, the heights of the layered light and heavy mineral layers are H ₁ and H ₂ , respectively, and their volume concentrations during natural accumulation are λ ₀₁ and λ ₀₂ , respectively, and the bed bottom area is A. Then, by changing the center of gravity from the bottom surface, the potential energy after stratification can be calculated as:

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According to calculations, the weight of the dressing stone in general, with a light mineral content is 0.4 to 0.5 fastest stratified, with the reduction in the amount of the upper jig heavy minerals beneficiation, reducing the speed of delamination, it can be considered evidence of the above relationship.
According to the theory of potential energy, the use of static stratification conditions has achieved good results in production. At present, the Meyer theory has been regarded as the basic principle of re-election stratification in the mineral processing industry.
D layered dynamics [next]
According to the above-mentioned potential energy theory, as the stratification progresses, the stratification speed is lowered, so that the amount of heavy minerals entering the bottom layer per unit time is considered to be proportional to the amount of heavy minerals remaining in the upper mixed layer. From this, the hierarchical dynamic relationship of the heavy mineral recovery yield ε with time t can be written:

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Although the formula (24) is identical in form to the formula (21), the amount of heavy minerals that can no longer be recovered due to the disturbance of the medium has been deducted. This formula can be used as the basis for establishing a mathematical model for vertical flow sorting.
3. The unity of dynamics and static stratification theory [next]
The free sedimentation of the particles, when the final settling velocity is reached, the gravity of the particles is balanced by the buoyancy and resistance of the fluid. Buoyancy is the static pressure of a fluid. Its size is proportional to the volume of particles (d ³ ), so the effective gravity of a particle per unit volume in a medium is only related to its density, regardless of its particle size. The resistance is the dynamic pressure of the fluid. It can be seen from the resistance formula R=ψd ² Ï… ² ρ (see the classification). Its size increases with the particle surface area (d ² ), so the resistance acting on the unit volume will vary with the particle size. The increase is reduced and there is a relationship when the free settling reaches equilibrium:

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