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NEUTRONIC ACTIVATION IN QUANTITATIVE ANALYSIS AND AUTOMATION OF CAF2 ORE FLOTATION.

Ziel

IT IS EXPECTED TO OBTAIN A SIMPLE SYSTEM OF DOSING COMPOUNDS OR ELEMENTS, USING THE NEUTRONIC ACTIVATION TECHNIQUE, TO BE APPLIED IN FLUORSPAR PROCESSING PLANTS OR FOR OTHER MINERALS.
IT SUBSTITUTES X-RAY FLUORESCENCE METHOD GENERALLY USED IN THIS ANALYSIS TYPE, BUT NOT APPLICABLE FOR FLUORSPAR FOR THE LOW ATOMIC NUMBER OF F.

THE DEVELOPEMENT OF THE SYSTEM WILL ALLOW CONTROL, AUTOMATION AND OPTIMIZATION OF FLUORSPAR PROCESSING PLANTS.
The automated control of a flotation plant requires real time quantitative analysis of the pulp in strategic points, such as feed, concentrate and tailing. Analysis with classical methods requires too long a time to be compatible with the running time of a flotation plant. Furthermore, the X-ray fluorescence analysis technique is intrinsically limited in its applicability in the case of light elements.

The aim of this project is to prove the operative feasibility of an on line analysis to be used to automate control of the flotation process for ores containing mostly fluospar. In this regard, a careful evaluation of actual conditions imposed by operative realities of a flotation process suggested the nuclear activation as a suitable technique.

The nuclear activation took place with 14 MeV neutrons generated by a 400 KV electrostatic accelerator; chemically pure calcium fluoride BaCO3 and amorphous silicon were used as reference samples. Radiation, idle and counting times were 300, 60 and 60 seconds respectively; thus the total time for the analysis of each sample was 7 minutes, which is compatible with the running speed of the flotation plant.

Starting from these experiences attention was mainly devoted to study a simple device for nuclear activation method based on the use of so called sealed tube as source of 14 MeV neutrons.

For nuclear activation analysis 2 different approaches were selected. The first method is based on simultaneous irradiation as well as simultaneous counting of the sample with unknown fluorite content and an appropriate standard with the same autoabsorption coefficient for gamma radiation. The second one is based on the determination of a calibration curve and monitoring of neutron flux by foil activation of thermal energy. In both cases a KAMAN neutron generator Model A-800 was used.

The aim of the project was to prove the operative feasiblitiy of an online analysis based on nuclear activation using 14 MeV neutrons. This online analysis method was to be used to automate control of the flotation process for ores containing mostly fluorspar. The thermoluminescence technique was also forecast as a subsidiary method in those points of the flotation cycle where less precision is acceptable.

For nuclear activation analysis 2 different approaches were selected. The first method was based on simultaneous irradiation as well as simultaneous counting of a sample with an unknown fluorite content and an appropriate standard with the same autoabsorption coefficient for gamma radiation. The second one was based on the determination of a calibration curve and monitoring of neutron flux by foil activation of thermal energy. In both cases a KAMAN neutron generator Model A-800 was used.

As far as the thermoluminescence technique was concerned, great care was devoted to testing the performances of the SOLARO model analyzer by Vinteen and to the development of technical procedure for sample preparation.

The nuclear activation technique was applied to samples with calcium fluoride concentrations ranging from 6% to 98%. Results fitted a cubic function even in the case of a low number of experimental points. Clearly, the actual irradiation time (45 minutes) required by the KAMAN neutron source was too long with respect to the running time of a flotation plant; however, this situation could be greatly improved by using much more intense, commercially available, sources.

An improvement in the glow curves reproducibility was achieved by the adoption of the appropriate particle size distribution. The values of the thermoluminescence (TL) signal as a function of calcium fluoride concentration, both in the tailing and concentrate, showed a linerar relationship in both cases and the method is valid for determination of variations of calcium fluoride concentration of about 1%.
THE RESEARCH DEALS WITH THE ADAPTATION OF THE CONTINUOUS ANALYSIS, BY NEUTRONIC ACTIVATION, TO THE CONTROL AND AUTOMATION OF THE FLOTATION PROCESSES OF FLUORSPAR MAINLY MINERALIZED ORE. THE STUDY WILL BE CARRIED OUT BOTH IN LABORATORY AND IN THE PLANT AND WILL CONSIST OF:

- SIGNIFICANT PROCESS PLANT POINTS IDENTIFICATION
- SAMPLES SIZE OPTIMIZATION
- SAMPLES OF THE PLANT AND STANDARD SAMPLES SET UP
- NEUTRONIC ACTIVATION
- DATA RESULT PROCESSING
- PRELIMINARY PROJECT FOR AN APPARATUS
- ECONOMIC EVALUATION OF THE RESULTS.

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Finanzierungsplan

CSC - Cost-sharing contracts

Koordinator

Nuova Mineraria Silius SpA
EU-Beitrag
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Adresse
Viale Merello 14
09123 Cagliari
Italien

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Letzte Aktualisierung: 23 Januar 1994

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Permalink: https://cordis.europa.eu/project/id/MA1M0061/de

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