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Dynamic Modelling of a Carbon-in-leach Gold Processing Plant
Thesis (MEng)--Stellenbosch University, 2022.
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| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2022
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| _version_ | 1867613906096095232 |
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| access_status_str | Open Access |
| author | Schultz, Sebastian Kent |
| author2 | Dorfling, Christie |
| author_browse | Dorfling, Christie Schultz, Sebastian Kent |
| author_facet | Dorfling, Christie Schultz, Sebastian Kent |
| author_sort | Schultz, Sebastian Kent |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2022. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/124747 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:43:35.067Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/124747 Dynamic Modelling of a Carbon-in-leach Gold Processing Plant Schultz, Sebastian Kent Dorfling, Christie Stellenbosch University. Faculty of Engineering. Dept. of Process Engineering. Leaching Adsorption Gold mines and mining UCTD Thesis (MEng)--Stellenbosch University, 2022. ENGLISH SUMMARY: Carbon-in-pulp (CIP) and carbon-in-leach (CIL) circuits have been the primary methods used for treating gold ores for many years. Although inherently robust processes, there is still often much room for optimisation to improve gold extraction efficiencies and to reduce reagent consumption and operating costs. A number of models for leaching and adsorption have been developed over the years so that these processes may be better understood. These models have been used for the simulation of CIP and CIL plants, with the aim of providing a tool for plants which can assist in decisions regarding plant design, operation and optimisation. The aim of this project was to develop and validate a dynamic model of the CIL section of a gold tailings retreatment plant. This was achieved by first developing a conceptual model, then computerising it in MATLAB and finally by validating it against plant data. Additionally, the effect of the choice of the adsorption isotherm used in the model was investigated. A conceptual model was developed by setting up the mass balance equations governing the flow of species through the CIL tanks. The adsorption was described by the classical film diffusion model. For the leaching, the model proposed by De Andrade Lima & Hodouin (2005) was selected . The conceptual model was computerised by coding it in MATLAB and rate constants were fitted to the plant data. Conceptual model validation was performed and showed that the model was able to respond appropriately to changes in the model parameters and inputs. Statistical analysis confirmed that the model responses to these parameter and input changes were statistically significant. Operational validation was performed using the plant data and the trends observed in the data were predicted by the model. However, the model did not give highly accurate predictions of the plant data. The average gold loading on carbon in the CIL tanks was under predicted by approximately 45% and the gold in solution was over predicted by around 53%. The inaccuracy of the model was attributed to the poor quality of the plant data used to develop the model. The frequency of the available plant data was very low for the development of a dynamic model, resulting in a low overall model accuracy. Three different adsorption isotherms, namely the linear, Langmuir and Freundlich isotherms, were each used to model the CIL plant in order to determine which adsorption isotherm predicts the plant data best. It was found that the linear and Langmuir isotherms performed best, giving very similar predictions of the plant data, while the Freundlich isotherm gave less accurate predictions than the aforementioned two. Although the model developed does not give highly accurate predictions of the plant data, it still follows the general trends in the data relatively well and responds appropriately to changes in the plant operating conditions. Therefore, the model can be a useful tool in predicting the general trends in plant data and for evaluating the effects of changes in feed and other operating conditions. AFRIKAANS OPSOMMING: Koolstof-in-pulp en koolstof-in-loging bane is die primêre metodes wat reeds vir baie jare vir behandeling van gouderts gebruik word. Alhoewel dit inherent robuuste prosesse is, is daar dikwels steeds beduidende ruimte vir optimering om goud ekstraksie doeltreffendheid te verbeter en om reagens verbruik en bedryfskostes te verminder. ʼn Aantal modelle vir loging en adsorpsie is oor die jare ontwikkel sodat hierdie prosesse beter verstaan kan word. Hierdie modelle is gebruik vir die simulasie van koolstof-in-pulp en koolstof-in-loging aanlegte, met die doel om ʼn hulpmiddel vir aanlegte te verskaf wat bystand kan verleen met besluitneming rakende aanlegontwerp, bedryf en optimering. Die doel van hierdie projek was om ʼn dinamiese model van die koolstof-in-loging seksie van ʼn gouduitskot herverwerkingsaanleg te ontwikkel en die geldigheid van die model te bepaal. Die doel is bereik deur eerstens ʼn konsepsuele model te ontwikkel, deur dit daarna te rekenariseer in MATLAB, en laastens deur die geldigheid van die model teen aanlegdata te bepaal. Die effek van die keuse van die adsorpsie isoterm wat in die model gebruik word is ook ondersoek. ʼn Konsepsuele model is ontwikkel deur die massabalans vergelykings op te stel wat die vloei van komponente deur die koolstof-in-loging tenks bepaal. Die adsorpsie is beskryf deur die klassieke film-diffusie model. Die model wat deur De Andrade Lima & Hodouin (2005) voorgestel is, is gebruik om die loging te beskryf. Die konsepsuele model is gerekenariseerd deur dit in MATLAB te kodeer en tempokonstantes is op die aanlegdata gepas. Konsepsuele model validasie is uitgevoer en het getoon dat die model op ʼn gepaste wyse reageer op veranderinge in model parameters en insette. Statistiese analises het bevestig dat die model se reaksies op hierdie veranderinge in parameters en insette statisties beduidend was. Die model se geldigheid is bepaal deur model uitsette teen aanlegdata te vergelyk; die tendense wat in die aanlegdata waargeneem is, is deur die model voorspel. Die model het egter nie hoogs akkurate voorspellings van die aanlegdata gemaak nie. Die gemiddelde goudlading op koolstof in die koolstof-in-loging tenks is ondervoorspel met ongeveer 45% en die goud in oplossing is oorvoorspel met ongeveer 53%. Die onakkuraatheid van die model is toegeskryf aan die lae kwaliteit van die aanlegdata wat gebruik is om die model te ontwikkel. Die frekwensie van die beskikbare aanlegdata was baie laag vir die ontwikkeling van ʼn dinamiese model, wat ʼn lae algehele model akkuraatheid tot gevolg gehad het. Drie verskillende adsorpsie isoterme, naamlik die lineêre, Langmuir en Freundlich isoterme, is elkeen gebruik om die koolstof-in-loging aanleg te modelleer ten einde te bepaal watter adsorpsie isoterm die aanlegdata die beste voorspel. Daar is gevind dat die lineêre en Langmuir isoterme die beste presteer het en baie soortgelyke voorspellings van die aanlegdata gee, terwyl die Freundlich isoterm minder akkurate voorspellings as die voorafgenoemde twee isoterme gegee het. Alhoewel die model wat ontwikkel is nie hoogs akkurate voorspellings van die aanlegdata maak nie, volg die model se voorspellings die algemene tendense in die data relatief goed en dit reageer toepaslik op veranderinge in die aanleg se bedryfstoestande. Die model kan daarom nuttig wees om die algemene tendense in aanlegdata te voorspel en om die effekte van veranderinge in voer en ander bedryfstoestande te evalueer. Masters 2022-03-09T09:29:38Z 2022-04-29T09:30:29Z 2022-03-09T09:29:38Z 2022-04-29T09:30:29Z 2022-04 Thesis http://hdl.handle.net/10019.1/124747 en_ZA Stellenbosch University application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Leaching Adsorption Gold mines and mining UCTD Schultz, Sebastian Kent Dynamic Modelling of a Carbon-in-leach Gold Processing Plant |
| title | Dynamic Modelling of a Carbon-in-leach Gold Processing Plant |
| title_full | Dynamic Modelling of a Carbon-in-leach Gold Processing Plant |
| title_fullStr | Dynamic Modelling of a Carbon-in-leach Gold Processing Plant |
| title_full_unstemmed | Dynamic Modelling of a Carbon-in-leach Gold Processing Plant |
| title_short | Dynamic Modelling of a Carbon-in-leach Gold Processing Plant |
| title_sort | dynamic modelling of a carbon in leach gold processing plant |
| topic | Leaching Adsorption Gold mines and mining UCTD |
| url | http://hdl.handle.net/10019.1/124747 |
| work_keys_str_mv | AT schultzsebastiankent dynamicmodellingofacarboninleachgoldprocessingplant |