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Calcium sulfite, or E226 Calcium sulphite, is a chemical compound, the calcium salt of sulfite with the formula CaSO3·x(H2O).
Two crystalline forms are known, the hemihydrate and the tetrahydrate, respectively CaSO3·½(H2O) and CaSO3·4(H2O).
All forms are white solids.
CAS: 10257-55-3
MF: CaH4O3S
MW: 124.17
EINECS: 233-596-8
Synonyms
Sulfurous acid, calcium salt;calcium sulphite;sulfurous acid, calcium salt (1:1);Calciumsulfit;CalciumSulfitePowder
E226 Calcium sulphite is most notable as the product of flue-gas desulfurization.
Calcium sulfite is a chemical compound that contains calcium, sulfur and oxygen.
E226 Calcium sulphite is typically used as a food additive, although it can also be used as a treatment for wastewater.
E226 Calcium sulphite reacts with hydrogen fluoride to form calcium fluoride and hydrogen sulfide.
This reaction is reversible, but only if the pH of the solution is greater than 2.
In addition to this reaction, E226 Calcium sulphite can react with sodium citrate to form an alkanoic acid and hydrogen sulfate.
The reaction mechanism of these reactions has not been fully elucidated, but genotoxic effects have been observed in animals following exposure to high concentrations of calcium sulfite.
E226 Calcium sulphite, also known as calcium sulphite, is a food additive commonly used in the food industry.
As a preservative, E226 Calcium sulphite plays a significant role in extending the shelf life of various food products by preventing the growth of bacteria, molds, and yeast.
E226 Calcium sulphite, also known as E226, is a chemical compound used as a preservative in the food industry.
E226 Calcium sulphite's main purpose is to prevent the growth of bacteria, mold and yeast, helping to prolong the shelf life of food products.
E226 Calcium sulphite is a calcium salt of sulfuric acid, characterized by its ability to maintain freshness and prevent color changes in food, especially in dried and fermented products.
E226 Calcium sulphite is particularly valued for its antioxidant and antimicrobial properties.
E226 Calcium sulphite is safe to use, provided the permitted standards are observed, however, people sensitive to sulfites should be cautious, as it can cause allergic reactions.
E226 Calcium sulphite, or calcium sulphite, is a chemical compound, the calcium salt of sulfurous acid with the formula CaSO3.
In presence of moisture E226 Calcium sulphite commonly forms the hemihydrate CaSO3.0.5H₂O.
E226 Calcium sulphite's uses as the pure compound are limited, such as a food additive, but it is produced in large quantities during flue gas desulfurization (FGD) with lime, which then exposed to air converts to common calcium sulfate (CaSO4, more exactly the gypsum form, CaSO4.2H₂O) by oxygen scavenging, this route of CaSO4 production via CaSO3 intermediate being the main source of drywall wallboard.
E226 Calcium sulphite Chemical Properties
Melting point: 600°C
density: 33.3[at 20℃]
solubility: slightly soluble in ethanol; soluble in acid solutions
form: solid (rough estimate)
color: white
Water Solubility: 0.0043g/100mL (18°C), 0.001g/100mL (100°C) H2O; slightly soluble alcohol; soluble in acid solutions with SO2 evolution [MER06] [CRC10]
EPA Substance Registry System: E226 Calcium sulphite (10257-55-3)
E226 Calcium sulphite has the chemical formula CaSO₃.
E226 Calcium sulphite is a calcium salt of sulfurous acid, appearing as a white, unstable powder that reacts with oxygen to form calcium sulphate.
Under acidic conditions, E226 Calcium sulphite forms sulfurous acid, which has preservative, oxidizing, and bleaching properties, but can also reduce the vitamin content in foods.
E226 Calcium sulphite is valued for a number of properties that make it an important additive in the food industry.
E226 Calcium sulphite acts as a strong preservative, preventing the growth of unwanted microorganisms.
In addition, thanks to its antioxidant properties, E226 Calcium sulphite helps preserve the natural color of food, which is especially important for fruits and vegetables.
E226 Calcium sulphite is also used in the production of alcohols, where it prevents fermentation and oxidation.
Uses
E226 Calcium sulphite can remove residual chlorine from water, including combined residual chlorine (NH2Cl, NHCl2, and NCl3) and free residual chlorine (ClO-, HOCl, and Cl2).
Compared with traditional activated carbon, E226 Calcium sulphite has a more efficient chlorine removal effect, is safer, more resistant to high temperatures, and does not breed bacteria.
E226 Calcium sulphite is widely used in various water treatments for residual chlorine removal in Southeast Asian countries and regions such as Japan, South Korea, Malaysia, and Taiwan.
E226 Calcium sulphite is used in a wide range of food products.
E226 Calcium sulphite is added to dried fruits to prevent them from turning brown, to wines and juices as a preservative, and to some grain and meat products to prolong their freshness.
In the food industry, E226 Calcium sulphite is also used to stabilize and improve the texture of fermented products.
Water treatment
Used in some shower filters to remove chlorine due to its reducing properties and slow dissolution in water.
Drywall
E226 Calcium sulphite is generated as the intermediate in the production of gypsum, which is the main component of drywall.
A typical US home contains 7 metric tons of such drywall gypsum board.
Food additive
As a food additive E226 Calcium sulphite is used as a preservative under the E number E226.
Along with other antioxidant sulfites, E226 Calcium sulphite is commonly used in preserving wine, cider, fruit juice, canned fruit and vegetables.
Sulfites are strong reducers in solution, they act as oxygen scavenger antioxidants to preserve food, but labeling is required as some individuals might be hypersensitive.
Wood pulp production
Chemical wood pulping is the removal of cellulose from wood by dissolving the lignin that binds the cellulose together.
E226 Calcium sulphite can be used in the production of wood pulp through the sulfite process, as an alternative to the Kraft process that uses hydroxides and sulfides instead of sulfites.
E226 Calcium sulphite was used, but has been largely replaced by magnesium and sodium sulfites and bisulfites to attack the lignin.
Gypsum
There is a possibility to use calcium sulfite to produce gypsum by oxidizing (adding O2) E226 Calcium sulphite in water mixture with the manganese (Mn2+) cation or sulfuric acid catalyzers.
Production
E226 Calcium sulphite is produced on a large scale by flue gas desulfurization (FGD).
When coal or other fossil fuel is burned, the by product is known as flue gas.
Flue gas often contains SO2, whose emission is often regulated to prevent acid rain.
Sulfur dioxide is scrubbed before the remaining gases are emitted through the chimney stack.
An economical way of scrubbing SO2 from flue gases is by treating the effluent with Ca(OH)2 hydrated lime or CaCO3 limestone.
Scrubbing with limestone follows the following idealized reaction:
SO2 + CaCO3 → CaSO3 + CO2
Scrubbing with hydrated lime follows the following idealized reaction:
SO2 + Ca(OH)2 → CaSO3 + H2O
The resulting E226 Calcium sulphite oxidizes in air to give gypsum:
2 CaSO3 + O2 → 2 CaSO4
The gypsum, if sufficiently pure, is marketable as a building material.
