Objectives and content
Currently produced base metal concentrates contain penalty cost minor elements like mercury, arsenic, antimony, bismuth, thallium, which are considered as deleterious impurities. These elements show a harmful influence on the furnace and refining operation. Their presence in concentrate provide numbers of environmental problems in metallurgical and refining processes. There is also a problem with the produced unwanted waste containing those very hazardous heavy metal elements.
It was found that the minor elements are very often well disseminated in certain ore mineral components. This finding allows to propose a different strategy for the removal of penalty cost elements where the effort is concentrated on the elimination of carrier minerals of minor elements. Unfortunately separation of carrier minerals by flotation is not simple in practice because the minor elements are able to modify to a large extent the surface properties of the carriers in a very unpredictable way. The minor elements modify the electronic properties of sulfide minerals which are semiconductors. This alters their properties in the interaction with flotation reagents and in a consequence change their flotation behavior (kinetics, or flotation edges).
On the basis of the knowledge available to the partners of this project at the present time, three approaches for batter separation and significant limitation of waste production are proposed: (i) to determine of flotation conditions to avoid a collective flotation of carrier minerals with metal base minerals, (ii) to find a very selective depressant of carrier minerals and solution conditions to achieve an optimal depression, (iii) to find collectors of carrier minerals for their very selective froth flotation. The two first solutions are preferred. In the third process concentrate of minor elements will be produced and if it will be found only as a waste by-product it can be efficiently diluted by blending with the tail flotation product.
This short-term project is proposed mainly on the basis of quite recently obtained results in another industrial project. The new very promising findings will be explored here mainly in a fundamental approach.
A systematic study of 2-3 systems with major carrier minerals will be investigated in detail. Successful completion of the project weight heavily on the determination of the qualitative and - quantitative relationships between occurrence of the minor elements and their major carriers, and the detailed determination of the mechanisms of surface phenomena taking place between carrier minerals and aqueous solution of different reagents. Therefore, it is very important to adopt the analytical methods which can offer (i) high surface sensitivity, (ii) spatial resolution, and (iii) in-situ capability. Therefore, most modern very sensitive spectroscopic methods supported by computer assistance will be used in proposed studies, including the recently developed in our laboratory new infrared reflection technique, which will provide detailed quantitative information about the composition and the structure of the surface layer, showing a unique capability for performing studies in in-situ conditions. Thus, it is proposed to carried out experiments with the use of mineral samples from different points of industrial flotation flowsheet and from related laboratory tests, where the flotation conditions (all separation steps) will be modelled.
Funding SchemeCSC - Cost-sharing contracts
7780 Castro Verde