Salt and Mineral Recovery from High Salinity Waters

Natural salt springs in the Salt Fork Basin in Crosby County, Texas, result in the natural salt pollution of the Brazos River, rendering it unusable for most potable purposes. Previous research indicates that by intercepting the source of the pollution, water quality of the Brazos River can be greatly improved. This paper investigates and assesses two strategies for salt and mineral recovery using natural brine collected from the Salt Fork Basin, the first of which is presented in a separate work. The research described in this paper evaluates the potential of a desulfation, soda-caustic softening, acidification/decarbonation, and evaporation process to obtain high purity salts through the use of PHREEQ-C modeling software in conjunction with laboratory scale tests. This treatment method was then compared via cost-benefit to previous treatment alternatives tested. This treatment demonstrates its effectiveness for the removal of both sulfate and softening, resulting in a sodium chloride purity of 99.7%. However, the residual concentrations of the alkaline earth metals used to desulfate the water result in an expensive softening stage. This paper concludes that the cost-benefit of a softening and acidification treatment is thus better suited for the generation of high purity when compared to the treatment method studied