Pneumatic jigging: Influence of operating parameters on separation efficiency of solid waste materials.
This article aims to provide insights into the factors that contribute to the separation efficiency of solid particles. In this study, a pneumatic jigging technique was used to assess the separation of solid waste materials that consisted of copper, glass and rubber insulator. Several initial experiments were carried out to evaluate the strengths and limitations of the technique. It is found that despite some limitations of the technique, all the samples prepared for the experiments were successfully separated. The follow-up experiments were then carried out to further assess the separation of copper wire and rubber insulator. The effects of air flow and pulse rates on the separation process were examined. The data for these follow-up experiments were analysed using a sink float analysis technique. The analysis shows that the air flow rate was very important in determining the separation efficiency. However, the separation efficiency may be influenced by the type of materials used.
The effect of jigging time and air cycle on bed stratification in a pilot scale Baum jig
A highly instrumented and controlled pilot jig was constructed to study water motion behaviour or oscillation with the object of optimizing bed stratification of coal washing jigs. Durable synthetic material, colour coded for density, was used as the bed material in a series of 114 experiments. The bed was fully analysed layer by layer for size and density distribution. It was found that jigging time is a very significant parameter affecting the bed stratification. In general, bed stratification improves quickly up to a jigging time of 180 s, and thereafter more slowly. When the jigging time exceeds 300 s, the bed is in a state of dynamic equilibrium for material coarser than 8 mm; however, the finer particles (< 8mm) need more time to achieve such a state. To improve the bed stratification, operating parameters should be adjusted to generate suitable air and water behaviour in the jig. A cycle with a long inlet period (199-220 °), which is seldom used at present, appears to provide such behaviour. Improvement of bed stratification by using an appropriate air cycle will increase the separation efficiency and yield of product in coal washing jigs.
A new energy dissipation theory of jig bed stratification. Part 1: energy dissipation analysis in a pilot scale baum jig
Abstract The dynamic energy dissipation within a jigging cycle has been mechanically analyzed using data developed in a highly instrumented and controlled pilot scale Baum jig. The analysis is based on the use of the energy and momentum equations for the fluid. It was found that energy balances on the water in the jig failed to close because of elastic deformation of the jig body, rather than inaccuracies in the measurement techniques or failure to account for heat transfer. This deformation problem appears to be common in either pilot jigs or commercial jigs. An empirical means of correcting the energy balance was devised and applied to the data with some success. Using this compensation method, the energy balance was improved. The likely energy balance indicates that (i) less than 7% of the energy of the incoming compressed air is expended in the jig system, (ii) less than 5% of the energy from the compressed air is actually dissipated in the jig bed, (iii) the kinetic energy input from the hutch water supply is effectively negligible, in comparison to the energy input from the compressed air, and (iv) about 2.5–3.7% of the energy from compressed air is dissipated around the bed plate.