Food grade Industrial grade 99% sodium hexametaphosphate CAS 10124-56-8

What is sodium hexametaphosphate? How does it work?

Sodium hexametaphosphate, also known as sodium hexametaphosphate, is a cyclic polymer of sodium metaphosphate with the chemical formula Na6P6O18 ((NaPO3)6) and CAS number 10124-56-8. It is a colorless, transparent, glassy solid or white powder, readily soluble in water. It is an important inorganic polyphosphate, widely used in industrial fields such as boiler and circulating cooling water softening and scale inhibition, detergent additives, cement hardening promoters, metal rust prevention, mineral processing flotation, printing and dyeing, papermaking, and oil drilling, due to its strong chelating ability for calcium and magnesium ions, as well as its dispersing, corrosion inhibiting, and interface modification properties.

Basic information : Chinese name: Sodium hexametaphosphate (also known as sodium hexametaphosphate, sodium metaphosphate glass, Gluconate salt); English name: Sodium hexametaphosphate (abbreviation SHMP); CAS number: 10124-56-8; Molecular formula: Na6P6O18 ((NaPO3)6); Molecular weight: 611.77; Melting point: approximately 616℃; Density: approximately 2.18 g/cm³; Easily soluble in water (dissolves slowly), insoluble in organic solvents, aqueous solution pH: approximately 6; Other names: Gluconate salt, Cargan, Sodium metaphosphate glass, SHMP, etc.

Structurally , sodium hexametaphosphate consists of six tetrahedral phosphate (PO4) atoms linked end-to-end in a ring, with six sodium ions distributed around the ring structure. Its chemical formula is Na6P6O18. In the glassy form, the chain length is not entirely uniform, but the overall structure is based on cyclic polyphosphate groups. The cyclic anions carry multiple negative charges, which is the structural basis for its strong chelating ability for polyvalent metal ions such as calcium and magnesium, and its adsorption and dispersion effect on particle surfaces—this is the root of the molecule's function in industry.

Physically , sodium hexametaphosphate is a colorless, transparent glassy flake or white granular crystalline powder, odorless; it is readily soluble in water but dissolves slowly, and is insoluble in organic solvents; its aqueous solution is weakly acidic (pH about 6); its density is about 2.18 g/cm³, and its melting point is about 616℃; it is highly hygroscopic, and its surface becomes sticky after absorbing moisture, so it needs to be stored in a sealed, moisture-proof container.

Chemically , sodium hexametaphosphate is a typical polyphosphate: it has a significant chelating ability for metal ions such as calcium and magnesium, forming soluble complexes that soften hard water and block free metal ions; it is easily hydrolyzed to orthophosphate in warm water, acid, or alkaline solutions; it can form precipitates with ions such as lead, silver, and barium, and these precipitates can be redissolved in excess sodium hexametaphosphate solution; its aqueous solution has buffering capacity; it is chemically stable and should be stored dry.

Why does sodium hexametaphosphate play these roles in industries such as water treatment, washing, building materials, mineral processing, printing and dyeing, papermaking, and petroleum? Its mechanism of action mainly includes the following:

Chelating softening and scale inhibition mechanism : Cyclic polyphosphate anions form soluble complexes with calcium and magnesium ions, locking hard water ions in the solution and preventing them from depositing as scale—this is the basis for the application of water softeners and scale inhibitors in circulating water.

Dispersion and anti-settling mechanism : Polyphosphate ions with multiple negative charges are adsorbed on the surface of particles, pigments and mud particles. The repulsion of like charges keeps the particles dispersed and suspended, preventing agglomeration and sedimentation. This is the basis for flotation dispersion, slurry diffusion and drilling mud conditioning applications.

Corrosion inhibition film formation mechanism : Phosphates can be adsorbed on the metal surface and form a protective film, which isolates water and corrosive media and slows down metal corrosion - this is the basis of rust prevention and corrosion inhibition applications.

Interface modification mechanism : adsorbed at the interface of minerals, fibers and cement particles, it changes the surface charge and wettability, promotes flotation separation or improves particle bonding strength - this is the basis of mineral processing and building material applications.

Process water quality regulation mechanism : It chelates impurity ions such as iron and calcium in water and has buffering capacity, improving the hardness and purity of process water in printing and dyeing, papermaking, chemical industry and other industries, providing stable process water quality for various industries.

All uses of industrial-grade sodium hexametaphosphate

1. Water treatment and soft water field

Boiler water softener

Used for softening boiler water in power plants, locomotives, and rolling stock to prevent scale buildup.

Corresponding products: boiler water softener, scale inhibitor, etc.

Industrial circulating cooling water treatment agent

It acts as a corrosion and scale inhibitor for circulating cooling water, preventing scale and corrosion in pipes and heat exchange equipment.

Corresponding products: circulating water treatment agents, corrosion and scale inhibitors, etc.

Industrial water softening

Used for softening water in dye production, titanium dioxide production, printing and dyeing sizing and dyeing, color film processing, chemical and reagent production, etc.

Corresponding products: industrial water softeners, process water treatment agents, etc.

2. Detergent industry

Detergent additives

It softens the washing water and chelates calcium and magnesium ions to prevent dirt and calcium soap from redepositing, thus improving cleaning power.

Corresponding products: laundry detergent, laundry liquid, industrial cleaning agents, etc.

3. Building materials sector

Cement hardening accelerator

Accelerate cement setting and hardening, and improve construction progress and strength development.

Corresponding products: cement hardening accelerators, concrete admixtures, etc.

High-temperature binder

Used for bonding and molding of high-temperature products such as refractory materials.

Corresponding products: refractory materials, high-temperature binders, etc.

4. Metal processing and rust prevention

Metal surface treatment and rust inhibitors

Used for metal surface treatment and rust prevention, protecting metal parts from rusting during processing and storage.

Corresponding products: rust inhibitors, metal surface treatment liquids, etc.

Rust prevention for oil drilling pipes

Rust protection for oil drilling pipes.

Corresponding products: rust inhibitor for drilling pipes, etc.

5. Mineral Processing and Petroleum Sector

Flotation dispersants and mineral inhibitors

It acts as a dispersant for fine-grained minerals, which is beneficial for desliming; and as an inhibitor for phosphate-type minerals, it improves the beneficiation effect.

Corresponding products: flotation reagents , mineral dispersants, mineral processing aids, etc.

Oil drilling mud conditioner

Used to adjust the viscosity of oil drilling mud.

Corresponding products: drilling mud additives, etc.

6. Textile, paper and leather industries

Fibers and bleaching/dyeing cleaning agents

Used for cleaning in the fiber and dyeing industries to remove impurities during processing.

Corresponding products: dyeing and printing auxiliaries, bleaching and cleaning agents, etc.

Coated paper pulp dispersant

It is used as a pulp dispersant in coated paper production to improve penetration.

Corresponding products: coated paper, coated paper pulp, etc.

Tanning aids

Used in leather tanning processes to improve water quality and tanning effectiveness.

Corresponding products: tanning auxiliaries, leather processing auxiliaries, etc.

7. Chemical reagent field

Analytical chemical reagents

It is used as a general analytical reagent in soil analysis, radiochemistry, and analytical chemistry experiments.

Corresponding products: analytical reagents, soil analysis reagents, etc.

Summary

Sodium hexametaphosphate (CAS 10124-56-8) is a cyclic polyphosphate composed of six tetrahedral phosphate molecules linked end-to-end. Its cyclic, multi-charged anions endow it with strong calcium and magnesium chelating abilities. Combined with its multiple properties of dispersion, anti-settling, corrosion inhibition, film formation, and interface modification, it has become a versatile ingredient in industry—boilers and circulating water systems rely on it for scale prevention, laundry detergent for softening hard water, cement for accelerating hardening, metals for rust prevention, flotation for dispersion, and drilling mud for viscosity adjustment. It is hidden behind laundry detergent, water softening equipment, cement construction, and printing paper, unassuming yet indispensable. Understanding its cyclic polyphosphate structure and chelating dispersion mechanism explains its enduring popularity in numerous industrial fields.