This study investigated the development potentials in the mineral processing plant of Björkdal. The flotation processes were explored with the purpose of finding out how to achieve a higher and a more uniform gold recovery with adapted choices of parameters. A material balance was carried out to describe in what flows the gold was distributed the current day of sampling. The material was sampled, prepared, and analysed according to gold grade. The sampling method of grab sampling was used and samples from seven occasions during the day were added and created the sample of the day. The sizes of the samples were based on experience but were checked by the Gy´s sampling formula. The sampling was performed during three days and the results were compiled in three material balances, one of which was a fraction balance. The pulp flow, the solid flow and the gold flow were documented as material balances. Deficiencies in the form of imbalances between inflows and outflows were corrected by a method of data reconciliation. The balanced measured values were used for analysis and documentation.In the mine of Björkdal the pH values were measured in the flotation processes. The residence times of the flows through the flotation plant was calculated from the material balance. The additions of reagents were noted and scaled down to the conditions of the laboratory. The conditioning was not included in the Björkdal process.In the flotation experiments at the Mineral processing laboratory, Luleå University of Technology, the influence of the adaptable parameters on the gold recovery was investigated. The following parameters were included in the experiments: pH, flotation time, particle sizes, conditioning time, and reagents additions. The conditions in the Björkdal plant were scaled down to correspond to those of the flotation cells of RÅ0 and RÅ1-3. For the experiments the material was sampled from the RÅ0 entry flow and from the Flotation entry flow. The material samples from the Flotation entry flow replaced the RÅ1-3 entry flow to imitate the conditions of the RÅ1-3 cell. This simplification was motivated by the practical sampling conditions.The results showed that it was possible to achieve a higher gold recovery by adapting pH, residence time and particle sizes. The gold recovery appeared to be independent of conditioning time. The experiment with reagent additions as parameter indicated that higher reagent additions resulted in faster flotation in the introduction part of the process. The report summarized graphically the measurements from the material balance and the flotation experiments in order to give best possible survey of the dependences between parameters and gold recovery. The experiments made it obvious that higher gold recovery resulted in lower gold grade. Therefore a compromise of adjustment between gold recovery and gold grade is important to consider. Variations of the gold recovery could be connected to the geological conditions. In the report significant results were documented. / <p>Validerat; 20130618 (global_studentproject_submitter)</p>
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:ltu-57633 |
| Date | January 2013 |
| Creators | Josefsson, Sofia |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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