Sodium gluconate is a white granular, crystalline solid which is very soluble in water. It is non corrosive, non toxic, biodegradable and renewable. It is resistant to oxidation and reduction even at high temperatures. The main property of sodium gluconate is its excellent chelating power, especially in alkaline and concentrated alkaline solutions. It forms stable chelates with calcium, iron, copper, aluminium and other heavy metals. It is a more superior chelating agent than EDTA, NTA and phosphonates.
Uses for Sodium Gluconate:
- Used as surface cleaning agent for metals
- Used as cleaning agent of glass bottles
- It also can be used as water reducing agent and retarder in the building industry. Sodium gluconate is also an efficient set retarder and a good plasticiser & water reducer for concrete, cement, mortar and gypsum.
Sodium gluconate in the cleaning industry
Sodium gluconate is commonly found in many household and industrial cleaners. This is because on its multi functionality. It acts as a chelating agent, a sequestering agent, a builder and a redeposition agent. In alkaline cleaners like dishwasher detergents and degreasers it prevents hard water ions (magnesium and calcium) interfering with the alkalies and allows the cleaner to perform to its maximum ability.
Sodium gluconate helps as a soil remover for laundry detergents as it breaks the calcium bond holding the dirt to the fabric and further prevents the soil redepositing onto the fabric again.
Sodium gluconate helps to protect metals like stainless steel when strong caustic based cleaners are used. It helps to break down scale, milkstone and beerstone. As a result it finds application in many acid based cleaners especially those formulated for use in the food industry.
Industrial Applications of sodium gluconate
Sodium gluconate is used in electroplating and metal finishing because of its strong affinity for metal ions. Acting as a sequestrant it stabilises the solution preventing impurities from triggering undesirable reactions in the bath. The chelation properties of gluconate assist in the deterioration of the anode thus increasing plating bath efficiency. Gluconate can be used in copper, zinc and cadmium plating baths for brightening and increasing luster.
Sodium gluconate is used in agrochemicals and
in particular fertilisers. It helps plants and crops to absorb necessary minerals from the soil.
It is used in the paper and pulp industries where it chelates out metallic ions which cause problems in the peroxide and hydrosulphite bleaching processes.
Sodium gluconate in Construction Industry
Sodium gluconate is used as a concrete admix. It offers several benefits including improved workability, retarding setting times, reducing water, improved freeze-thawing resistance, reduced bleeding, cracking and dry shrinkage. When added at a level of 0.3% sodium gluconate can retard setting time of cement to over 16 hours depending on ratio of water and cement, temperature etc. As it acts as a corrosion inhibitor it helps to protect iron bars used in concrete from corrosion.
Sodium gluconate as a corrosion inhibitor
When sodium gluconate is present in water above 200ppm it protects steel and copper from corrosion. Water pipes and tanks composed of these metals are prone to corrosion and pitting caused by dissolved oxygen in the circulation water. This leads to cavitation and degradation of the equipment. The sodium gluconate reacts with the metal producing a protective film of the gluconate salt of the metal eliminating the possibility of the dissolved oxygen to come into direct contact with the metal.
In addition sodium gluconate is added to deicing compounds like salt and calcium chloride which are corrosive. This helps protect metal surfaces from being attacked by the salts but not deterring from the salt's ability to dissolve ice and snow.
Other industrial applications of importance include bottle washing, photo chemicals, textile auxiliaries, plastics and polymers, inks, paints and dyes and Water treatment.
Properties & specification of sodium gluconate:
- Systematic name: sodium (2R,3S,4R,5R')-2,3,4,5,6-pentahydroxyhexanoate
- Other names: D-Gluconic Acid, Monosodium Salt; Natriumgluconat; D-Gluconsaure; Natriumsalz; Natrium D-Gluconat;
- Purity: 99+%
- CAS No: 527-07-1
- EINECS: 208-407-7
- Molar mass: 218.14 g/mol
- Chemical formula: NaC6 H11 O7
- Appearance: white crystalline solid
- pH: 6.5-7.3
- Solubility: soluble in water 590 g/l @ 25C
Sodium gluconate is soluble in cold water and hot water. It is only partially soluble in methanol and ethanol.
This product is not classified according to the EU regulations.
Safety phrase: S24/25- Avoid contact with skin and eyes.