Guar gum improved electrolyte compatibility. These changes in properties result in increased use in different fields, like textile printing, explosives, and oil-water fracturing applications. Guar molecules have a tendency to aggregate during the hydraulic fracturing process, mainly due to intermolecular hydrogen bonding. These aggregates are detrimental to oil recovery because they clog the fractures, restricting the flow of oil. Cross-linking guar polymer chains prevents aggregation by forming metal – hydroxyl complexes. The first crosslinked guar gels were developed in the late ‘60’s. Several metal additives have been used for crosslinking, among them are chromium, aluminum, antimony, zirconium, and the more commonly used,
Hydrochloric acid They range from those of water at very low concentrations approaching 0% HCl to values for fuming hydrochloric acid at over 40% HCl. Hydrochloric acid as the binary (two-component) mixture of HCl and HO has a constant-boiling azeotrope at 20.2% HCl and 108.6 °C (227 °F). There are four constant-crystallization eutectic points for hydrochloric acid, between the crystal form of HCl·HO (68% HCl), HCl·2HO (51% HCl), HCl·3HO (41% HCl), HCl·6HO (25% HCl), and ice (0% HCl). There is also a metastable eutectic point at 24.8% between ice and the HCl·3HO crystallization. Hydrochloric acid is prepared by dissolving hydrogen chloride in