Sodium hexametaphosphate, as one of the most widely used water treatment agent, is necessary for industrial water, domestic water and waste water disposal. It is soluble in water, the aqueous solution is alkaline and the PH value of 1% aqueous solution is 9.7. It can be gradually hydrolyzed into phosphite in water, which makes it have a good ability of complexing metal ions, which can be complexed with calcium, magnesium, iron and some other metal ions to form a soluble complex. It is only used to overcome the res water phenomenon previously, and has been slowly developed to be used in many other fields, such as, water treatment, food processing, mining, drilling, printing and dyeing, refractories industries.
Sodium hexametaphosphate uses in water treatment includes water for dye production, titanium dioxide production, water for printing and dyeing, water for color film copy cleaning, water for chemical industry, water softener for pharmaceutical and reagent production and water treatment agents for industrial circulating cooling water. It can also be used as corrosion inhibitor, flotation agent, dispersing agent, high temperature binder, dyeing aid, etc… Also applied to the surface treatment, such as, antirust agent, detergent additive, cement hardening accelerator, pulp diffuser to increase permeability, as well as wash utensils and chemical fibers to remove iron ions in the pulp. In the petroleum industry, it is used to prevent the rust of drill pipes and control the viscosity of mud during the oil drilling process.
Sodium Hexametaphosphate Water Softener
Sodium hexametaphosphate has the function of forming fixed soluble complexes with metal ions, especially alkali metal ions, which can effectively prevent the precipitation of hardly soluble salts of alkali metal. At the same time, it can also plat the role of removing the melting boiler and precipitation. So it is widely used in the softening of various industrial water. Because sodium hexametaphosphate has a greater complexing capacity for CA++ than other phosphates, it is widely used in industrial sectors that has high requirement of water quality, such as, electrolytic industry, boiler water for power stations and textile industry.
Sodium Hexametaphosphate Antiscalant
Scale inhibitor refers to a class of agents that have the ability to disperse insoluble inorganic salts in water, prevent or interfere with the precipitation and scale function of insoluble inorganic salts on the surface of metals, as well as maintain good heat transfer effects for metal equipment. Anti-corrosion and scale inhibitors for cold-exchange equipment are based on epoxy resin and specific amino resins, and adding appropriate amounts of various rust and corrosion inhibitors. It has excellent properties of shielding, impermeability, rust resistance, good scale resistance, thermal conductivity, as well as excellent resistance to weak acid, strong alkalis, organic solvents and other properties. Its adhesion is strong and the desert layer is bright, flexible, dense and hard.
The mechanism of the corrosion and scale inhibitor is divided into complexation and solubilization, lattice distortion, electrostatic repulsion. Complexation and solubilization action is that the copolymer dissolves in water and then ionizes, which can form a negative molecular chain. It forms a water-soluble complex or chelate with Ca2+, thus increasing the solubility of inorganic salt and playing a role in scale inhibitor. The effect of lattice distortion is that local functional groups in the molecule occupy a certain position on the crystal nucleus or microcrystal of the inorganic salt, hindering and destroying the normal growth of inorganic salt crystal, slowing the growth rate of crystal, thereby reducing salt scale formation. The electrostatic repulsion effect is that the copolymer dissolves in water and adsorbs on the crystallites of the inorganic salt, which increases the repulsive force between the particles, hinders their agglomeration, and keeps them in a good dispersed state, thereby avoiding or reducing the formation of scale.
Sodium Hexametaphosphate Corrosion Inhibitor
Sodium hexametaphosphate has two functions in metal corrosion inhibitors. First, it can slow down the corrosion of metal materials. Second, it can maintain the physical and mechanical properties of metal. The characteristics of polyphosphates is that phosphorus-oxygen bond can hydrolyze to produce orthophosphate ion, which is an anodic corrosion inhibitor. When the quantity of phosphate ion is insufficient, local corrosion is easy to occur. The greater harm is when the content of calcium ions in water is high, and the phosphate ions produced by hydrolysis are easy to form difficult calcium iodate precipitation. Precipitation corrosion inhibitors are often refered to safe corrosion inhibitors. Even the amount isn’t insufficient, it won’t increase metal corrosion. The adsorption mechanism of industrial sodium hexametaphosphate corrosion inhibitor is that the inhibitor has an adsorption effect on the metal surface and it will form an adsorption film on the metal surface, thereby generating the corrosion inhibition effect. The SHMP has the functions of both corrosion and scale inhibition.
The amount of sodium hexametaphosphate uses in water treatment is less, which won’t change the property of the corrosive medium and it doesn’t require other special equipment and surface treatment. This is why shmp chemical is common used in water treatment.