Calcium formate is the

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quanti ...

formic acid Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Est ...

. It is also known as E238. Under this

E number E numbers ("E" stands for "Europe") are codes for substances used as food additives, including those found naturally in many foods such as vitamin C, for use within the European Union (EU) and European Free Trade Association (EFTA). Commonly ...

it is used as an

animal feed Animal feed is food given to domestic animals, especially livestock, in the course of animal husbandry. There are two basic types: fodder and forage. Used alone, the word ''feed'' more often refers to fodder. Animal feed is an important input to ...

preservative A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or ...

within EU, but not in foods intended for people. Calcium formate is stable at room temperature, is inflammable and forms

orthorhombic In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with ...

crystals. The mineral form is very rare and called formicaite, and is known from a few boron deposits.

Uses

Calcium formate is used within EU as an animal feed preservative. It acidifies the feed thus preventing microbe growth and increasing shelf life. About 15 g of calcium formate addition per kg of feed lowers its pH by one. 15 g/kg is the maximum recommended feed concentration within EU – this level is thought to be safe for pigs, chickens, fish and

ruminant Ruminants ( suborder Ruminantia) are hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. Th ...

s. The compound is not environmentally harmful in feed use at these levels. Calcium formate prevents the growth

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

such as ''

E. coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escher ...

Pseudomonas aeruginosa ''Pseudomonas aeruginosa'' is a common encapsulated, gram-negative, aerobic– facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, ''P. aer ...

Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posit ...

'' and ''

Enterococcus hirae ''Enterococcus hirae'' is a species of ''Enterococcus''. Its type strain is NCDO 1258. It is involved in growth depression in young chickens and endocarditis and sepsis Sepsis, formerly known as septicemia (septicaemia in British English) or ...

'' in growth mediums. It also prevents the growth of

fungi A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...

like ''

Aspergillus niger ''Aspergillus niger'' is a mold classified within the ''Nigri'' section of the ''Aspergillus'' genus. The ''Aspergillus'' genus consists of common molds found throughout the environment within soil and water, on vegetation, in fecal matter, on de ...

'' and ''

Candida albicans ''Candida albicans'' is an opportunistic pathogenic yeast that is a common member of the human gut flora. It can also survive outside the human body. It is detected in the gastrointestinal tract and mouth in 40–60% of healthy adults. It is usua ...

''. However, the relevance of these experimental observations to feed preservation is not known. Calcium formate is used as a masking agent in the chrome tanning of leather. Calcium formate in tannage formulation promotes faster, more efficient leather penetration of the chrome. Calcium formate can also be used as a replacement for

in the pickling operation. As a

grout Grout is a dense fluid which hardens to fill gaps or used as reinforcement in existing structures. Grout is generally a mixture of water, cement and sand, and is employed in pressure grouting, embedding rebar in masonry walls, connecting sec ...

and

cement A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement m ...

additive, calcium formate imparts a number of desirable properties in the final product, e.g. increased hardness and decreased setting time. Its addition is desirable for work at low temperature and for inhibition of corrosion of metal substrates within cement/grout. It is also effective in the prevention of

efflorescence In chemistry, efflorescence (which means "to flower out" in French) is the migration of a salt to the surface of a porous material, where it forms a coating. The essential process involves the dissolving of an internally held salt in water, or ...

. In

drywall Drywall (also called plasterboard, dry lining, wallboard, sheet rock, gypsum board, buster board, custard board, and gypsum panel) is a panel made of calcium sulfate dihydrate (gypsum), with or without additives, typically extruded between thi ...

(gypsum board), calcium formate can function as a

fire retardant A fire retardant is a substance that is used to slow down or stop the spread of fire or reduce its intensity. This is commonly accomplished by chemical reactions that reduce the flammability of fuels or delay their combustion. Fire retardants ...

. Calcium formate and

urea Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important ...

mixtures are effective

deicer Deicing is the process of removing snow, ice or frost from a surface. Anti-icing is the application of chemicals that not only deice but also remain on a surface and continue to delay the reformation of ice for a certain period of time, or preve ...

s, and tend to cause less corrosion of steel and cement surfaces relative to some other deicers.

Research

Calcium formate seems to be safe as a

calcium supplement Calcium supplements are salts of calcium used in a number of conditions. Supplementation is generally only required when there is not enough calcium in the diet. By mouth they are used to treat and prevent low blood calcium, osteoporosis, and ...

for people with one time doses of 3.9 g (1200 of calcium) per day. Increases in blood formate concentration have been observed with such doses, but in healthy subjects the formate does not accumulate, and is quickly metabolized. Calcium formate is shown to be more readily absorbed form of calcium than calcium carbonate and

calcium citrate Calcium citrate is the calcium salt of citric acid. It is commonly used as a food additive ( E333), usually as a preservative, but sometimes for flavor. In this sense, it is similar to sodium citrate. Calcium citrate is also found in some ...

. No optic nerve damage has been observed with calcium formate supplementation – along with

formaldehyde Formaldehyde ( , ) ( systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section ...

, formate is a major metabolic product of methanol, which can cause blindness upon ingestion. Calcium formate could be used to remove environmentally harmful (see acid rain)

sulfur oxides Sulfur oxide refers to many types of sulfur and oxygen containing compounds such as SO, SO2, SO3, S7O2, S6O2, S2O2, etc. Sulfur oxide (SO''x'') refers to one or more of the following: * Lower sulfur oxides (S''n''O, S7O2 and S6O2) * Sulfur mono ...

(SO_X) from fossil fuel exhausts of e.g. power plants. Calcium formate is added to wet calcium carbonate to promote the formation of

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and dr ...

when exhaust is run through it. This process is called wet flue gas

desulfurization Desulfurization or desulphurisation is a chemical process for the removal of sulfur from a material. This involves either the removal of sulfur from a molecule (''e.g.'' A=S → A:) or the removal of sulfur compounds from a mixture such as oil refin ...

(WFGS). Gypsum binds sulfur oxides thus reducing their release to the environment via exhaust. Calcium formate seems to be more effective than or almost equally as effective as some other industrially used WFGS agents.

Production

Calcium formate is formed as a co-product during

trimethylolpropane 300 C--> Trimethylolpropane (TMP) is the organic compound with the formula CH3CH2C(CH2OH)3. This colourless to white solid with a faint odor is a triol. Containing three hydroxy functional groups, TMP is a widely used building block in the polyme ...

production. Hydrated lime (

calcium hydroxide Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca( OH)2. It is a colorless crystal or white powder and is produced when quicklime ( calcium oxide) is mixed or slaked with water. It has m ...

) is used as the source of calcium.

Butyraldehyde Butyraldehyde, also known as butanal, is an organic compound with the formula CH3(CH2)2CHO. This compound is the aldehyde derivative of butane. It is a colorless flammable liquid with an unpleasant smell. It is miscible with most organic solvents. ...

and

react in a water solution in the presence of a basic

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

, forming an unstable

intermediate product Intermediate goods, producer goods or semi-finished products are goods, such as partly finished goods, used as inputs in the production of other goods including final goods. A firm may make and then use intermediate goods, or make and then sell, o ...

, dimethylol butyraldehyde (DIMBA). DIMBA reacts further with formaldehyde to give trimethylolpropane and calcium formate. Calcium formate is separated from the solution, heat treated to remove formaldehyde and then dried. Calcium formate can also be made from calcium hydroxide and

carbon monoxide Carbon monoxide ( chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

at high pressure and temperature – e.g., at 180 °C and 35

atm ATM or atm often refers to: * Atmosphere (unit) or atm, a unit of atmospheric pressure * Automated teller machine, a cash dispenser or cash machine ATM or atm may also refer to: Computing * ATM (computer), a ZX Spectrum clone developed in Mo ...

. It may also be made from

calcium chloride Calcium chloride is an inorganic compound, a salt with the chemical formula . It is a white crystalline solid at room temperature, and it is highly soluble in water. It can be created by neutralising hydrochloric acid with calcium hydroxide. Cal ...

and

Safety

Pure calcium formate powder irritates eyes severely, but causes no skin irritation. Powder inhalation can be dangerous. The compound has a stinging taste. Ingesting liquids with high calcium formate concentrations cause severe gastrointestinal lesions.

References

{{Calcium compounds Calcium compounds Formates Concrete admixtures