An Overview of Pakistan Rock Salt Resources and Their Chemical Characterization | Pakistan Journal of Scientific and Industrial Research (Series A: Physical Sciences) 2021

Syed Asim Hussain Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Science, Xining, China; Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Xining, China; University of Chinese Academy of Science, Beijing, China

Han Feng-Qing Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Science, Xining, China; University of Chinese Academy of Science, Beijing, China

Ma Yunqi Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Science, Xining, China; University of Chinese Academy of Science, Beijing, China

Hawas Khan Department of Earth Sciences, Karakoram International University, Gilgit, Pakistan

Yang Jian Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Science, Xining, China; Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Xining, China;

Gulfam Hussain Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China

David Widory GEOTOP/Earth and Atmosphere Sciences Department, UQAM, Montréal, Quebec, Canada

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 201718. 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.