Recovery of high purity sodium chloride from seawater bittern by precipitation-evaporation method

Abstract

Seawater bittern is a liquid that still exists after most of the NaCl has crystalized in the production of salt from seawater. The main components of the liquid are MgCl2 and NaCl. This study aims to recover the NaCl present in bittern through the precipitation method with NaOH and evaporation. The initial stage of this research was collection of bittern in the salt production process in a salt pond. The obtained bittern samples were then added with NaOH to precipitate the MgCl2 components as Mg(OH)2 and leave NaCl as filtrate. The precipitate and the filtrate were separated by filtration. The obtained NaCl filtrate is then evaporated to obtain high purity NaCl. The product obtained was then determined the NaCl contents by argentometric titration. NaCl crystal was characterized using FTIR spectroscopy XRD spectroscopy, and Scanning Electron Microscope (SEM). The recovery results showed that the NaCl obtained had a high purity of 98.75% w/w and yield 30,45%. The IR spectra and diffractogram obtained showed compatibility with the characteristics of the reference NaCl.