Influence of the particle size on the calcium leaching from a hot metal desulphurisation slag (HMD)
- Format
- MasterThesis
- Status
- publishedVersion
- Description
Precipitated calcium carbonate (PCC) is a valuable material that can be produced from steel industry waste. Particularly, hot metal desulphurisation (HMD) slags are steel industry waste with high calcium oxide contents which can be extracted by means of leaching with different solvents. In fact, calcium extraction is a unit operation within the PCC processing plant. One of the slag?s properties that show significant influence on the calcium extraction by leaching is its particle size distribution. Therefore, the main objective of the study was to investigate the influence of three selected HMD slags? particle sizes [(250-500) ?m, (500-710) ?m, (710-1000) ?m] on the calcium extraction efficiency using 2M ammonium chloride as solvent, solid-to-liquid ratio 100g/L, and extraction time 1 hour. Furthermore, special focusing on the slags? particle size is due to the aim of optimising and proposing a feasible large scale PCC plant design, where smaller particle sizes increase operational costs and capital investment. Calcium leaching was undertaken using a propeller mixing system, and samples were taken at 15, 30, 45, and 60min for each particle sizes. Calcium concentrations before and after leaching were measured by Atomic Absorption Spectroscopy (AAS). In addition, an aqua regia digestion method was performed in order to measure the calcium concentration of the fresh HMD slag by AAS. Calcium concentrations in the leachates samples and in the fresh slag samples were unexpectedly low if compared with literature data. Consequently, calcium extraction efficiencies were also low for each of the studied particle sizes, reaching a maximum of 21.1% for (250-500) ?m. Despite the low concentrations due likely to problems in the research methodology, the particle size range of (250-500) ?m has been suggested as a design parameter for PCC plant designs. Finally, recommendations in the research methods were stated taking into account special attention in the HMD slag conditioning as well as the determination of calcium concentration by AAS.
- Publication Year
- 2016
- Language
- eng
- Topic
- LIXIVIACI?N DE CALCIO
ESCORIA DE DESULFURACI?N (HMD)
CLORURO DE AMONIO
CARBONATO DE CALCIO PRECIPITADO (PCC))
- Repository
- Repositorio SENESCYT
- Rights
- openAccess
- License
- openAccess