Calcium carbonate

Catalog	ACM471341-9
CAS	471-34-1
Structure
Description	Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks as the minerals calcite and aragonite (most notably as limestone) and is the main component of pearls and the shells of marine organisms, snails, and eggs. Calcium carbonate is the active ingredient in agricultural lime and is created when calcium ions in hard water react with carbonate ions to create limescale. It is medicinally used as a calcium supplement or as an antacid, but excessive consumption can be hazardous.
Synonyms	Colloidal calcium carbonate
IUPAC Name	Calcium;carbonate
Molecular Weight	100.09
Molecular Formula	CCaO3
Canonical SMILES	C(=O)([O-])[O-].[Ca+2]
InChI	InChI=1S/CH₂O3.Ca/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2
InChI Key	VTYYLEPIZMXCLO-UHFFFAOYSA-L
Boiling Point	800 °C
Melting Point	825 °C
Flash Point	197ºC
Purity	99%+
Density	2.93 g/mL at 25 °C (lit.)
Solubility	Practically insoluble in water
Appearance	White-beige to slightly beige-gray random crystals
Storage	Store at +5 °C to +30 °C
pH	9
References	Andreja Pondelak, Andrijana Sever Škapin, Nataša Knez , Friderik Knez and Tomaž Pazlar. Improving the flame retardancy of wood using an eco-friendly mineralisation process.Green Chem., 2021, 23, 1130-1135.
RefractiveIndex	1.6583
Stability	Stable. Incompatible with acids, fluorine, ammonium salts, alum.

Case Study

Calcium Carbonate as a Synergist to Enhance the Flame-Retardant Effect of Intumescent Flame Retardant on Polyoxymethylene

Yang, Zheng, et al. Polymers, 2023, 15(3), 537.

Ammonium polyphosphate (APP) was modified using a titanate coupling agent and then combined with benzoxazine (BOZ) and melamine (ME) to create a novel intumescent flame retardant (Ti-IFR). This Ti-IFR, along with CaCO3 as a synergist, was incorporated into POM. The flame-retardant properties and underlying mechanism of the resulting composites were subsequently evaluated.
Flame-Retardant Properties
Analysis revealed that Ti-IFR primarily enhances flame retardancy in the gas phase, whereas CaCO3 reinforces the condensed phase barrier effect. Used together, they function independently while demonstrating a significant synergistic interaction. Specifically, a POM composite containing 29% Ti-IFR and 1% CaCO3 achieved a UL-94 V-0 rating. This composite exhibited a Limiting Oxygen Index (LOI) of 58.2%, an 81.1% reduction in average heat release rate (Av-HRR), and a 35.3% decrease in total heat release (THR).
Preparation Details of Ti-APP and Ti-CaCO3
Ti-APP: APP (200 g) was dispersed in industrial alcohol (400 mL) within a three-neck flask, stirred at 50 °C for 1 hour to form a uniform suspension. Separately, PN-201 (2 g) was ultrasonically dispersed for 0.5 hours in 10 mL of an equal-parts ethanol-water solvent. This PN-201 dispersion was then slowly added to the APP suspension, and stirring continued at 50 °C for another hour. The reacted suspension underwent negative pressure filtration, was washed several times with anhydrous ethanol, and the resulting filter cake was dried at 80 °C for 12 hours.
Ti-CaCO3: Modified CaCO3 (Ti-CaCO3) was prepared following the same procedure used for Ti-APP, employing CaCO3 (20 g), industrial alcohol (100 mL), and PN-201 (2 g).

Tin Oxide Coated Calcium Carbonate Serves as a Flame Retardant for Semi-Rigid Polyvinyl Chloride

Xu, Jianzhong, et al. Journal of applied polymer science, 2006, 101(1), 731-738.

The study prepared tin oxide (SnO2) coated (10%) calcium carbonate (CaCO3) for semi-rigid polyvinyl chloride (PVC) treatment purposes and then evaluated its flame retardant and smoke suppression properties against those of CaCO3 alone, SnO2 alone, and a CaCO3/SnO2 (9:1) mixture.
Key Findings
Semirigid PVC treated with SnO2-coated CaCO3 demonstrates higher limiting oxygen index values and char yields and achieves lower smoke density and mass smoke density ratings while forming a denser char structure than untreated semirigid PVC or semirigid PVC treated with equal amounts of CaCO3 and SnO2 individually or in combination. The treated semirigid PVC maintains tensile property levels similar to untreated versions while showing much greater impact strength against semirigid PVC that does not contain flame retardants.
Preparation of SnO2-coated CaCO3
In the preparation process, thirty grams of calcium carbonate were mixed into a slurry by vigorous stirring in 300 mL of an aqueous solution containing 4.4 g of sodium hydroxystannate and 10 g of urea. The slurry was then heated to 358 K and held at that temperature for 8 hours. Once the reaction mixture cooled to room temperature, the solid product was filtered from the solution, washed three times with distilled water, and air-dried at 383 K. The resulting dry solid was ground with a mortar and pestle, yielding 33.2 g of a fine white powder, corresponding to a yield of 98%. Analysis of this SnO2-coated CaCO3 indicates a composition of 9.64% SnO2 and 91.36% CaCO3, equating to a coating level of 10.67% w/w on the filler.

If the product of interest is not available in our catalog, please contact us to see if there is any relevant stock or other purchase channels.