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INVESTIGATE THE SYNERGIC EFFECTS OF SODIUM ETHYL XANTHATE (SEX) AND AMONIUM DITHIOPHOSPHATE (ADTP) ON NICKEL CONCENTRATE
GRADES AND RECOVERIES AT MUNALI CONCENTRATOR.BY
NYENDWA JANNY (METALLURGY STUDENT, UNZA 2015)
Supervisor Dr Witika.
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1. Introduction Munali Nickel Mine is the only nickel mine in
Zambia located about 80km south of Lusaka.The mine owns a processing plant which
treats sulphide nickel ore in the form of petlandite (NiFe)9S8.
Other minerals present include chalcopyrite,talc and pyrrhotite.
900,000tons of sulphide nickel ore per annum to produce 8,500-9,000tpG of nickel concentrate with an average 10% Ni grade.2
2 Problem statementConcentrator department ordered more than
100t of ADTP.This was done without any test work in the
plant or lab to ascertain suitability of ADTP as a flotation reagent for Munali ore.
The use of ADTP as a collecting reagent resulted in poor grades and recoveries for flotation.
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3 Main Objective To investigate the synergic effect of SEX and
ADTP on nickel recoveries and grades on a Munali concentrator.
Specific ObjectivesTo determine 80% passing 75microns.To obtain optimum recoveries and grades.To investigate the effect of dosages on
grades and recoveries.4
4. Literature ReviewIt is well documented that ADTP when used
with other collectors in the correct proportion or synergy enhances Ni recoveries and improves grades. (CYTEC, 2010)
ADTP gives an improved selectivity in the flotation of sulphide ore especially when used in synergy with some xanthates.
Low pH conditions affect grades (Wills, 2006).Synergy improves properties such as collecting
power and selectivity.5
5. Methodology and Materials 5.1 Sample Preparations
Six 1kg samples were each subjected to grind tests.
Each was milled at different times.
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5. MethodologyFigure:5.1 Flow Sheet
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UG Sampling ORE CRUSHING MILLING
FLOTATIONDRYINGFINAL CONCENTRATE
5. Methodology 5.1 Establishing 80% -75μm
The pulp sent to the oven to remove water for 24hrs.
100g of the sample was homogenized. Employed the wet screen analysis.Grind size is a critical parameter for optimum
recoveries and grade.To achieve the grinding tests, milling was done at
different residence time.80% -75mμ is recommended for flotation for
Munali ore. 8
5. Methodology 5.1 Chemical Reagents
Sodium ethyl xanthate (SEX) and Ammonium Dithiophosphate.-collection of nickel and other valuable minerals.
Guar gum depressant-depressant of pyrite and talc
Lime-ph adjustment.Frother-froth stabilization Ore Prep F-549.
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5.Methodology 5.4 Reagents Preparations
Table 5.1:Conditioning Stage
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Reagents Dosage (gpt) Addition stage
Collector 100, 120, 150* Conditioning
Guar 500 Conditioning
Frother As required to maintain froth Conditioning
Lime 1000 Conditioning
5. Methodology5.6 Flotation Tests
1kg ore was milled for 25mins.The pulp was taken to the flotation cell for
flotation.And reagents were added accordingly.Conditioning was done for 2mins before
flotation.And collection was done at every 3mins
between every successful roughers.11
5. Methodology5.6 Flotation Test Cont.
Flotation tests were done using a lab flotation cell at 650rpm and air blown at a volumetric flow rate of 3.0l/min.
Four different rougher concentrates were collected.
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5. Methodology5.6 Flotation Tests
Figure: 5.2 Trial flotation
experiment in a flotation cell.
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5. MethodologyFigure:5.3 Lab flotation test-flow sheet
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6.Results and Discussions6.1 Establishing 80% passing 75μm
Table 6.1:Results of time and %passing 75μm.
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TIME (MINS) % PASSING 75μm
5 25
10 48
15 64
20 75
25 80
30 90
6. Results Fig 6.1: Graph of grind of mesh.
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6.ResultsFig 6.2 Graph of grades/recoveries
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6. Results and Discussions.
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6. Results and discussions.
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6. Results and Discussions
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6. Recoveries and Grades
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6. Results and Discussions• Increase in synergic ratios resulted in increase of
recoveries.• Increase in synergies yielded a general decrease in
grades.• There were inconsistent grades at 120gpt.• Dosages generally resulted in increased recoveries
and decreased grades.• Synergies yielded higher recoveries than pure a
collector at 1:0 compared to 1:1, 2:1, and 3:1.22
7.Conclusion and Recommendations
• Optimum results were at 100gpt 3:1, recovery 77% and grade 3.6%.
• Optimum recoveries were obtained at 120gpt ratio 1:1 .
• Optimum grades were obtained at 100gpt ratio 3:1• Maximum recovery was obtained 150gpt ratio 3:1• Unmonitored pH and selectivity of collectors are
suspected contributors to poor grades.• Increased recoveries were as a result of synergies.
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7. Conclusions and Recommendations
• Use of a pH meter is recommended to ascertain the results.
• The project should be revisited with the same parameters but with new chemicals.
• The concentrate should be assayed for various minerals including pyrite and talc.
• The mineralogy of the concentrate should be investigated.
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8. References• Mining Chemicals HANDBOOK. (2004). CYTEC.• Rao T. C., Govindarajan, B., and Barnwal, J. P. (1995), “A Simple Model for Industrial Coal Flotation Operation”, High-Efficiency Coal
Preparation (Kawatra, ed.), Society for Mining, Metallurgy, and Exploration, Littleton, CO, pp. 177-185.• Wills, B. (2006). Mineral Processing Technology. 6th ed. Oxford:Butterworth-Heinemann.• Zulu, H. (2011). Munali Nickel Mine Flotation Report.
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