Enrichment and extraction of lanthanum from Belitung silica sand using sulfuric acid heap leaching, precipitation and complexation with phytic acid

Abstract

In this study, enrichment and extraction of lanthanum from Belitung silica sand was carried out using heap leaching, precipitation and complexation methods. Complexation with phytic acid with impurities metal ions on pregnant leach solution (PLS) from silica sand at room temperature was also investigated. This method is cheap, practical, no destruction needed, and the preparation is simple and easy. The precipitation method using sodium sulfate was carried out to separate the metals and impurities present in the solution. The heap leaching of the metals was performed by varying the parameters such as acid concentration (0.001-3※M) and volume of sulfuric acid solution (50-250※mL). Concentration of lanthanide and composition of metal ions of samples were determined using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The optimum concentration and volume of H2SO4 as a leaching agent was 3※M and 250※mL, respectively, with the result of the lanthanum salt as high as 1.637※ppm. The hexaphosphate groups of phytic acid as active sites is favorable selective to bind with Al3+ metal ions, thus it is expected to have high effectiveness for lanthanum enrichment. From the ICP-OES results in the complexation using phytic acid, lanthanum was obtained of 0.709※ppm (11.29%) with its purity of ∼67%. These results suggested that lanthanum can be extracted from Belitung silica sand using the acid leaching, precipitation and complexation methods.