CHARACTERIZATION AND BENEFICIATION STUDIES ON LEAD – ZINC ORE DEPOSIT IN NAHUTA - GWANA, BAUCHI STATE, NIGERIA

Abstract

This research involved the characterization and beneficiation studies on Lead-Zinc Ore deposit in Nahuta - Gwana, Bauchi State, Nigeria. The research was carried out on a sourced ore from Nahuta Gwana a boundary area between Bauchi and Taraba states. The sourced sample was crushed and pulverized using laboratory jaw crusher and pulverizing machines respectively. The pulverized sample was characterized to determine its chemical and mineralogical compositions, liberation size, work index and beneficiated to metallurgical grade using Shaking table and Froth flotation concentration method. The Energy Dispersive –X-ray flouresecence chemical analysis of the homogenized Nahuta Gwana ore using ED - XRF revealed that the ore contained 6.75 % Pb and 20.67 % Zn on the average, which meets the typical standard feed grades of 1 – 5 % Pb and 1 – 10 % Zn usually required for mining lead-zinc ore. The mineralogical analysis using X-ray diffraction technique revealed that the ore contained 4 % galena (PbS) and 15 % sphalerite (ZnS) as the major valuable minerals; 35 % Albite (NaAlSi3) and 46 % quartz (SiO2) as the main gangue. The liberation size of the ore was found to be - 250 + 180 μm and -63 + 45 μm and was prepared to 100 % passing these sieve ranges. The work index of the ore was evaluated as 19.7 kWh/ton using the Bond modified method. Ore sample of sieve – size - 250 + 180 μm was beneficiated via shaking table and the resulting concentrate assayed 3.43 % Pb and 48.30 % Zn at recovery of 73.9 %. The concentration and enrichment ratios of the process were 4.33 and 3.21 respectively. Froth flotation techniques were adapted to beneficiate ore sample of sieve size -63 + 45 μm. The resulting lead zinc concentrates assayed 4.58 % Pb : 66.61 % Zn at recoveries of 50.1 % and 74.8 % respectively. Concentration and Enrichment ratios for the lead and zinc concentrates were 3.95 ; 3.85 and 2.25 ; 2.13 respectively. On premise of these findings, It was concluded that froth flotation is the most suitable method of beneficiating the Nahuta Gwana lead-zinc ore deposit at a liberation size of – 63 + 45 μm.