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CONTRIBUTION OF CRYOMAGNETIC TECHNIQUES FOR WASTE CONTAINING NON-FERROUS METALS

Objective

The aim of this research project is to study the possible contribution of cryomagnetic techniques in the various stages of the hydro-metallurgy of waste containing recoverable non-ferrous metals.
A study was made of the possible contribution of cryomagnetic techniques in the various stages of the hydrometallurgy of waste containing recoverable nonferrous metals.

This technique holds particular promise in the case of operations for the extraction or separation of fine or perceptible metallic phases. Separation tests carried out on very fine grained solids confirmed the interest or cryomagnetism for separating paramagnetic substances.

The performance obtained by superconducting high field high gradient magnetic separation gave an insight into the magnetic treatment of heavy metals in rinse waters, derived from the surface finishing industries.

An interesting way has been found for creating a magnetic support for coprecipitation of the elements to be eliminated from solution with a hydrous iron oxide. A specific installation was designed as part of this research to remove magnetic metal hydroxides and coprecipitated magnetic and/or nonmagnetic metal hydroxides without stopping the magnetic field but by a simple chemical modification. A preliminary study has been done to automate the feedings of pulp and cleaning solution.

The research and development programme has led to confirmation of the interest of cryomagnetism separation as applied to nonferrous waste materials as well as to understanding of the technical difficulties of implementing this technique.

A technical economic study provides reference elements for the manufacturing of superconducting magnets coils, for application in the domain of nonferrous waste processing.
The cryomagnetic technique holds particular promise in the case of operations for the extraction or separation of fine or perceptible metallic phases. It should make it possible to improve or eliminate various stages in the process such as:
the recovery of effluent solids;
enrichment of value phases;
selection or extraction of industrially problematic colloidal complexes;
and purification of refining solutions and the control of waste.

This research programme will cover, as methodically as possible, the field of application of finely structured or perceptible metallic waste involving:
waste metallurgical and hydro-metallurgical units (special steels, copper, zinc, nickel, chromium, cobalt, cadmium);
surface treatment effluents;
industrial catalysts (chemicals, oils, etc);
motor vehicle catalysts (platinoids);
electrolytic baths;
and miscellaneous.

The operating conditions will be optimized in terms of:
prior characterization and conditioning of the fluxes to be processed (physicochemical analyses of the phases concerned, optimization of solids concentration and dispersion, techniques for precipitating the elements to be extracted);
adaptation of technology (hydrodynamism, residence times, fields, gradients and matrices);
and evaluation of performances (metallurgical balance, energy balance, miscellaneous consumption figures).

From these will be derived the basic information necessary for the study of the industrial feasibility of the process (design of a demonstration prototype).

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Bureau de Recherches Géologiques et Minières (BRGM)
Address
Avenue Du Concyr
45060 Orléans
France

Participants (3)

Fundación INASMET Asociación de Investigación Metalúrgica del País Vasco
Spain
Address
12,Camino De Portuetxe
20009 San Sebastián
GEC Alsthom Transport SA
France
Address
38 Avenue Kleber
75016 Paris
Institut National Polytechnique de Lorraine
France
Address
Rue Du Doyen Marcel Roubault
54501 Vandoeuvre-les-nancy