An Overview of Pakistan Rock Salt Resources and Their Chemical Characterization

Abstract

Rock salt is of importance for both humans and industries. In this study, we discussed the main salt deposits in Pakistan by evaluating the total reserves as well as the rock salt annual production and by characterizing their chemical composition (Na+, Ca2+, Mg2+, K+, B+, K+, Li+, Cl-, SO42-, Br- and NO3-). Our objectives were to document their impurity, water-insoluble matter and moisture contents to ultimately discuss whether the halite in Pakistan, in its natural form, is safe for human consumption. Pakistan rock salt deposits are located in two distinct regions: the Salt Range area in the Potwar sub-basin with huge Precambrian salt deposits and the Eocene Bahadurkhel/Kohat salts in the Kohat sub-basin. Total reserves are estimated over tens of billion tons with an annual production of about 3,534,075 metric tons in 2017-Results show that the halite of the salt range area is purer than the Bahadurkhel/Kohat salts with purity levels (expressed as NaCl) of 99 and 95 wt. %, respectively. Gypsum represents one of the main impurities in halite for both regions, while potash salts (>9 wt. %) are observed in the Salt Range area, K contents are very low in the Kohat salts. Although the halite moisture content is similar for both regions, impurities contents are higher (>5%) for the Kohat salts, arising the need for their purification prior to eventual human consumption.
 

The quality of hydrochloric acid produced according to technological routes, contaminants and industrial applications

“…The first using procedures similar to coal mining; As the salt is mechanically removed, tunnels are formed supported by columns of the salt itself. The other method of production consists of drilling wells up to the salt dome and, by means of a chosen well, hot water is injected, in such a way that the brine is continuously removed from other producing wells [10][11][12][13].…”

“…The main contaminants that may be present in hydrochloric acid will be analyzed, below: TOTAL IRON Generally, the total iron found in chemical analyses of hydrochloric acid is referred to as total iron, considering it in the form of Fe 2+ (ferrous) and Fe 3+ (ferric). The Fe 2+ ion may come from the contamination of sodium chloride obtained from solar evaporation from seawater or from the mining of rock salt [10][11][12][13]. Another possibility is the acid attack on carbon steel pipes, generating ferrous chloride according to the reaction:…”