Industrial waste—A valuable source of rare metals or a reclamation object?

The scope of the analysis embraces nine types of industrial waste: low-grade ore piles, pyrite cinder dumps, tailings dumps, wet magneti c separation and flotation tailings ponds, phosphogypsum piles, red mud ponds, as well as dumps of metallurgical and electric power industries. The prospects of using the industrial waste as a source for production of rare metals, rare earths and other by-products are discussed. The practical interest lies only in the use of low-grade ore and pyrite cinder. Recovery of valuable components from the other types of industrial waste is incapable to solve the problem connected with the waste management but can only aggravate it. It is expedient to extract valuable components from waste of current processing, in amount to be sufficient to satisfy the related demand. To this effect, it is necessary to create new no-waste technologies. This is the way taken by Russia’s largest companies RUSAL and ROSTEC: reduction in cost of the main production releases finds for the implementation of environmental and nature-oriented activities.The problem connected with the use of many millions of tons of ecologically hazardous old waste is solved in a big way by means of reclamation, which is only possible in association with the government, through establishment of a public institution on industrial waste management.

Obtaining low-energy cement from industrial raw material

The results of obtaining Portland cement by lowenergy technology using technogenic raw materials are presented. Coal wastes and tephritobasalt in a ratio of 1: 1 were used as the clay component, instead of scarce pyrite cinder, granular lead slags were used. The regularities of the influence of the compositions of the blends, saturation coefficient, silicate and alumina modules, firing modes on the chemical and mineral composition and quality of clinker and cement are established. The composition of the raw mixes was calculated according to the ROCS program, the content of free CaO in the clinker was determined. The strength of experimental cement was tested after 7 and 28 days of hardening. Its physical and mechanical characteristics and structure were studied.

Assessing the possibility of solidification and stabilization of pyrite cinder by using quicklime and fly ash

The aim of this study was to determine the possibility of using two low-cost binders,quicklime and fly ash for the solidification/stabilization (S/S) of pyrite cinder.Pyrite cinder, used in this study, represents a remnant from sulfuric acid productionin fertilizer factory IHP “Prahovo” A.D. (Serbia), and has a very high toxicmetal content. High contents and leachability of copper, lead and zinc make thiswaste material hazardous, representing an extraordinary risk to the environment.In order to determine the leaching behavior of the S/S mixtures, four single-stepleaching tests were performed, each one having a different sort of leaching fluid(deionized water, inorganic and organic acidic solutions). X-ray diffraction (XRD),scanning electron microscope (SEM) and energy dispersive X-ray analyzer (EDS)were implemented to elucidate the mechanisms responsible for immobilization ofCu, Pb and Zn. Overall, the test results indicated that S/S treatment using bothquicklime and fly ash was effective in immobilizing these metals, especially whenthere is a higher share of binder present. Treated waste can be safe for disposal andeven considered for “controlled utilization”. Furthermore, the use of fly ash for S/Streatment of pyrite cinder solves the disposal problems of two waste types, as it alsorepresents a secondary industrial product.