The preparation of metallic residues in processing technology proves challenging due to numerous factors that have to be considered when treating these wastes. The reprocessed waste materials are diverse in form and consist predominantly of large, high-volume shavings (different grain size distribution) which could be contaminated with impurities such as coarse metallic fragments or oils. The overall aim when treating metallic waste products is to produce high-quality secondary raw materials for the metallurgical industry by using mechanical treatment processes, thus maximizing the value of secondary raw materials. This dissertation is based on a careful survey of the various metallic residue (scrap) types, qualities and quantities available on the market. The characterization of metallic waste and the associated processing challenges encountered are addressed. The main focus of this research however is on the processing of metal shavings. Additionally, mention is made of industrial processing units currently in use for the treatment of these various scrap types. Briquetting was identified as the main processing step in the preparation of metallic shavings, whereas the systematic trials illustrated that the preparation of the shavings are of vital importance influencing the briquette quality. On one hand the metallic residues are de-oiled to comply with the legal statutory waste standards while on the other, the shaving bundles need to be crushed sufficiently to be processed into high-density briquetted recycled materials. Trials involving selected metal shavings (shred) used in the market were carried out using different shredding units. Emphasis was placed on the influence of impurities on the shred and its quality after effective crushing. Trials using different crushing machinery on selected metallic shavings available on the market were made with emphasis on how impurities influence the quality of the shred after milling. Based on the results to these experiments (particularly concerning roughage and briquette density), a new crushing unit using the concept of a radial gap rotor shear was developed. This was equipped with intelligent measurement technology reading relevant parameters such as torque, speed and rotor position which can be monitored continuously. From the trial findings a marketable radial gap rotor shear was developed which has an ejection for roughage thus setting new standards for energy-efficient processing of metallic waste materials. The radial gap rotary shear has been integrated into the existing product portfolio of the company ATM Recyclingsystems and has helped the company redefine its machine provider role to a provider of complete solutions in the field of preparation of metallic residues. The import and significance of this process is acknowledged by the fact that in the meantime ten shaving preparation and briquette processing plants are subsequently successfully implemented worldwide, i.e. by the Austrian company Kuttin in Knittelfeld.
|Translated title of the contribution
|Development of a radial gap rotary shear for crushing metal shavings: a major contribution to the preparation of high-quality briquettes for the metallurgical industry
|Published - 2016
Bibliographical noteembargoed until null
- metal shavings
- processing technology
- rotary shear