Ekstraksi Kalsium Dari Brine Geothermal Menggunakan Metode Chemical Precipitation

Akbar Ramadhan; Satria Ridho Illahi

Authors

Akbar Ramadhan Politeknik Negeri Sriwijaya Author
Satria Ridho Illahi Politeknik Negeri Sriwijaya Author

Keywords:

geothermal brine, calcium, chemical precipitation, sodium oxalate, gypsum

Abstract

Geothermal brine is liquid waste from geothermal power plants that contains various minerals, including calcium, which can cause scaling in piping systems. This study aims to extract calcium from geothermal brine of PT Pertamina Geothermal Energy Tbk. using the chemical precipitation method with sodium oxalate, followed by conversion into calcium sulfate dihydrate (gypsum) through a reaction with sulfuric acid. The process begins with the precipitation of calcium oxalate from brine by adding sodium oxalate at a temperature of 25–35°C with varying reaction times. The calcium oxalate precipitate is then reacted with sulfuric acid at different molar ratios to produce gypsum. The results show that a 1:4 molar ratio and 40 minutes of reaction time yielded the optimal outcome, with a conversion yield of 98.80% and water content of 19.48% in the product. Elemental analysis using XRF revealed that the calcium and sulfur contents in the gypsum were close to theoretical values, indicating successful conversion. This study demonstrates that geothermal brine can be utilized as an alternative raw material for gypsum production while supporting sustainable waste management practices.

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