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 application of mineral processing techniques for the recovery of metal from post-consumer wastes
Abstract Mineral processing techniques are dominant, and have a very wide field of application, in the secondary metals industries — only the final stages of raw material production involve any chemical operations. There are many basic similarities between primary and secondary feeds — in general the values and gangue materials can be differentiated from each other by several differences in physical properties — however, there are many difficulties encountered in applying techniques developed for separation of minerals to post-consumer waste. Primary feeds to mills are homogeneous when compared to the feed treated by a secondary operation — the heterogeneous nature of scrap feeds causes a lot of problems to the processor. Other characteristics of waste tend to be higher metal content (and metal, rather than mineral, particles), high liberation sizes, and unusual particle shapes. Nearly all methods of concentration utilised in the recycling industries have been developed from mineral beneficiation technology — the major exception is eddy current separation which relies on the presence of large conducting particles (such as the fist sized chunks of aluminium produced in autoshredding). At present applications of eddy current separators are almost exclusively for material reclamation — as eddy current separators suitable for finer feeds are developed it seems likely that they will be applied to primary mineral feeds.
Evaluation of Impact of Yarn Count and Stitch Length on Pilling, Abrasion, Shrinkage and Tightness Factor of 1 ? 1 Rib Cotton Knitted Fabrics
This study investigates the impact of yarn count and stitch length of 100% cotton knitted fabrics. 1 × 1 ribs structured fabrics were used in this research work. The stitch length 2.50 mm, 2.52 mm, 2.60 mm, 2.70 mm, 2.80 mm and 2.96 mm were used of the yarn count of 26Ne, 28Ne and 36Ne. The areal densities of the grey fabrics were in various amounts. The impacts of yarn count and stitch length were measured concerning pilling resistance, abrasion resistance, and shrinkage and tightness factor. The result showed that the fabric pilling grade decreased while number of cycle increased. Abrasion resistance decreased but length wise shrinkage increased despite the fact that the stitch length increased. The results also exposed that the tightness factor of the fabric increased with the increase of the stitch length in both dyeing and washing state and finished state compared to grey state for the yarn count 26Ne and homogeneous result not found for yarn count 28Ne and 36 Ne. Evaluation of Impact of Yarn Count and Stitch Length on Pilling, Abrasion, Shrinkage and Tightness Factor of 1 × 1 Rib Cotton Knitted Fabrics