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 regeneration on pyrohydrolysis and adiabatic absorption of hydrogen chloride in water, a process invented in the 1960s. However tightening environmental standards and stringent air permit policies render it increasingly difficult to establish new pyrohydrolysis-based acid regeneration plants. The following processes for the regeneration of HCl from spent pickle liquors have been adopted by the ferrous metals processing industry: Hydrothermal hydrolysis of hydrochloric SPL from carbon-steel pickling lines is a hydrometallurgical reaction, which takes place according to the following chemical formulae: 12 FeCl + 3 O → 8 FeCl + 2 FeO 2 FeCl + 3 HO → 6 HCl + FeO