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Surface phenomena and new reagent scheme for separation of feldspars from Quartz


Objectives and content:

The separation of feldspars from quartz by flotation applying the conventional HF-method is no longer acceptable from an environmental and health point of view. Moreover, new ceramic composite materials require high quality components for their industrial scale production. Therefore, the search for anew reagent scheme for selective and efficient separation is under serious consideration. Since only the selective modification of surface hydrophobicity of minerals components gives basis for their successful selective separation by flotation, the detailed surface characterization will be one of the goals of the project. The second objective is the proposition of a new reagent and flotation scheme for separation feldspars from quartz. Three groups of reagents more selective than those conventionally used are proposed for investigation. In this project, the metal cations activation and depression of the minerals in conventional anionic and cationic flotation, and the chelate/complex forming agents for feldspar - quartz separation will be explored through fundamental to pilot plant studies.

The main objectives of this project are: (i) the acid-base properties of the mineral water interface, (ii) surface complexation of metal cations that constitute the mineral lattice and isomorphous, (iii) surface complexation of the reagents leading to the evaluation of surface complexation constants, (iv) detail spectroscopic surface characterization of the nature and structure of the adsorbed new reagents on minerals (adsorption mechanisms, orientation molecules in the adsorption layer) in order to evaluate criteria for designing of the optimal structure of the new reagents for selective separation, (v) X optimisation of physicochemical parameters of selective adsorption and flotation response on laboratory scale with the chosen reagents, (vi) pilot plant flotation tests (about 20 ton of feldspar ore) and application tests of the produced final concentrate by end user.

The experimental methods include: potentiometric titration supported by computer programs FITEQL and SOLGASWATER, Infrared spectroscopic reflection techniques (DRIFT, ATR, IRAS) with a method recently developed by us which provides tremendous gain in detail interpretation of the surface phenomena taking place at mineral surfaces, and an X-ray photoelectron spectroscopy for in-situ an dex-situ spectroscopic surface characterization. Moreover, other conventional measurements will be carried out: adsorption isotherms, solubility, conductivity, surface tension, turbidity and flotation. The flotation tests will be carried out from micro laboratory to pilot plant scale. Although the aim of the project is to find a new reagent scheme for selective feldspar flotation, the results will be of great interest for many divers technical applications.

For example they could be directly used in flocculation, water treatment and in commercial production of mineral fillers for polymer composites. As an additional benefit of the proposed new process(es), it is also expected, that during selective separation of feldspars from quartz it will be possible, as a side effect, to lower significantly the content of iron which is another important issue for good quality felds parconcentrates. This project is characteristic of the fact that the fundamental understanding of the surface phenomena at a molecular and atomic level will be exploited immediately to optimise the flotation process of feldspar separation up to pilot plant scale, including economic evaluation of the proposed solutions. BE97-4378

Funding Scheme

CSC - Cost-sharing contracts


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Participants (4)

Rue Du Doyen M. Roubault
54501 Vandoeuvre-les-nancy
Universitetsområdet Persön
971 87 Lulea
MEVIOR - Mining and Industrial Minerals SA
77,Mitropoleos Street
54622 Thessaloniki
Tricorona Mineral AB
411 37 Göteborg