Basic Mechanisms of Gelling Agents

The formation of gels can be achieved by various chemical principles  

Commonly Used Salts, Crosslinkers, and Chelating Agents 

Aluminum citrate Chromium sulfate Ferrochromo-lignosulfonate Manganese nitrate Potassium hichromate Sodium bichromate Ferric acetylacetonate Ammonium ferric oxalate 

Aluminum trichloride, a cheap, abundant waste product of the chemical industry, forms a gel under certain conditions with carbonates and on mixing with alkalies. Laboratory and field tests showed that aluminum trichloride can be used as a gel-forming agent for reducing the permeability of waterconducting channels [673]. 

A similar process allows reacting triethyl phosphate and phosphorous pentoxide to form a polyphosphate in an organic solvent [871]. An excess of 1.3 moles of triethyl phosphate with respect to phosphorous pentoxide is the most preferred ratio. In the second stage, a mixture of higher aliphatic alcohols from hexanol to decanol is added in an amount of 3 moles per 1 mole phosphorous pentoxide. Aluminum sulfate is used as a crosslinker. Hexanol results in a high-temperature viscosity of the gel, while maintaining at a pumpable viscosity at ambient temperatures [870]. 

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