Calcium sulfate hemihydrate

• CAS: 10034-76-1
• Catalog Number: ACM10034761
• Category: Main Products
• Molecular Weight: 290.3
• Molecular Formula: CaH₂O5S
• Description: Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO4 and related hydrates. In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant. One particular hydrate is better known as plaster of Paris, and another occurs naturally as the mineral gypsum. It has many uses in industry. All forms are White solids that are poorly soluble in water. Calcium sulfate causes permanent hardness in water.
• Synonyms: CALCIUM SULFATE CALCINED;CALCINED GYPSUM;Calcium sulfate hemihydrate;CALCIUM SULPHATE 1/2 H₂O;CalciumSulphateDriedBp
• IUPAC Name: calcium sulfate hemihydrate
• Canonical SMILES: O.[O-]S(=O)(=O)[O-].[O-]S(=O)(=O)[O-].[Ca+2].[Ca+2]
• InChI: InChI=1S/2Ca.2H2O4S.H2O/c;2*1-5(2,3)4;/h;2*(H2,1,2,3,4);1H2/q2*+2;/p-4
• InChI Key: ZOMBKNNSYQHRCA-UHFFFAOYSA-J
• Melting Point: 1450ºC
• Appearance: White powder
• EC Number: 231-900-3
• Exact Mass: 289.8392057
• HS Code: 2833299090
• Hydrogen Bond Acceptor Count: 9
• Hydrogen Bond Donor Count: 1
• LogP: -0.32150
• Monoisotopic Mass: 289.8392057
• PSA: 97.87
• Rotatable Bond Count: 0
• Safety Description: S22-S24/25
• Stability: Stable. Hygroscopic.
• Storage Conditions: Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances.
• Topological Polar Surface Area: 178 Ų

Case Study

Calcium Sulfate-Based Medical Materials Prepared from α-Calcium Sulfate Hemihydrate

Tang M, et al. Materials Science and Engineering: C, 2010, 30(8), 1107-1111.

α-Calcium sulfate hemihydrate (α-hemihydrate) can be used to prepare calcium sulfate-based materials (CSBM), which has good biocompatibility, bioabsorption, osteoinduction and osteoconductivity. The crystal habit and particle characteristics of α-hemihydrate are important factors affecting the physical properties of CSBM. In this system, the α-hemihydrate process with an aspect ratio of 1 to 3:1, a maximum size of 125 μm, and good particle size distribution is suitable for obtaining high-performance medical CSBM.
Preparation of α-calcium sulfate hemihydrate-based CSBM
· First, α-hemihydrate crystals were prepared from reagent grade calcium sulfate dihydrate using a solvent-mediated phase change method. By adding different concentrations of materials and additives, crystals with aspect ratios of 0.5-1:1, 1-3:1 and 3-6:1 were prepared.
· The obtained α-calcium sulfate hemihydrate crystals with different aspect ratios were hydrated and hardened to prepare CSBM.
· The samples were tested for hydration properties, normal consistency, and hardened CSBM strength using a TAM air isothermal calorimeter, a consistency meter, and an automated compressor test, respectively.

Calcium Sulfate α-Hemihydrate for Oil Well Applications

Meireles P D S, et al. Journal of Cleaner Production, 2019, 220, 1215-1221.

Calcium sulfate α-hemihydrate (α-HH) is a material with high ecological potential and is considered a less environmentally aggressive coagulant than Portland cement. Hemihydrate has hydrating properties when in contact with water, and crystallizes and solidifies after a certain period of time, gaining mechanical resistance. Slurry systems based on α-HH as a basic coagulant for oil well cementing have been developed. The α-HH system with a water/gypsum ratio (WGR) of 0.5 showed the best results.
Slurry systems based on α-calcium sulfate hemihydrate
· Calcium sulfate α-hemihydrate (0.3672 mL/g) and fresh water were used for the formulations of the calcium sulfate based pastes.
· The additive used to enhance the technological parameters of the formulations were: a sodium tetraborate decahydrate (Na2B4O7.10H2O) retardant additive (0.5828 mL/g), polycarboxylate based dispersant (0.9088 mL/g), antifoam (1.0206 mL/g), glass G cement and bentonite.

Hydration characteristics of calcium sulfate hemihydrate

Chen, Xuemei, et al. Construction and Building Materials 296 (2021): 123714.

Although the dissolution/precipitation mechanism of hemihydrate hydration is widely recognized, in situ observation by environmental scanning electron microscopy (ESEM) provides more detailed information for the hydration of calcium sulfate hemihydrate. The hydration process is also monitored by many parameters, including phase, hydration degree, ion concentration, particle size, and morphology evolution with hydration time. The results show that calcium sulfate hemihydrate is porous and contains many nanopores. It dissolves from the water-accessible surface to form a transient flocculent intermediate with enlarged pores. Subsequently, large particles are broken into small particles due to crack connection, and then continue to dissolve, leaving some stubborn spots and finally disappearing. At the same time, gypsum precipitates in the first few minutes and evolves to the final crystalline structure through three main stages.
The calcium sulfate hemihydrate powder is stuck to the conductive adhesive on the sample holder with a toothpick. The loose powder is blown away with an air pump. The sample holder is placed on the cooling stage of the ESEM (Sirion by FEI) in environmental scanning mode for observation. First, an image of the original particle is taken and the observation point is marked. Then, set the temperature to 2°C to 2°C and the pressure to 600 to 800 Pa to produce condensation to hydrate the hemihydrate. Adjust the temperature and pressure for a period of time and observe the marked point, then repeat the adjustment and observation until the hydration is complete.

Calcium sulfate hemihydrate powder used as bone cement

Wang, Peng, et al.Journal of the American ceramic society 91.6 (2008): 2039-2042.

Calcium sulfate hemihydrate (CSH) powders used as bone cement were synthesized by heat treating calcium sulfate dihydrate (CSD) powders with various CaCl2 concentrations in boiling CaCl2 solution to control their morphology. All the prepared CSH powders showed X-ray diffraction peaks corresponding to the CSH structure without any secondary phase, implying a complete transformation from the CSD phase to the CSH phase. It was also observed that the concentration of CaCl2 significantly affected the morphology of the synthesized CSH powders. In other words, as the CaCl2 concentration decreased from 35.5 wt% to 23.5 wt%, the morphology transformed from slender hexagonal rods with an aspect ratio of 5.5 to fat short hexagonal columns with an aspect ratio of 1.4. The reduction in aspect ratio resulted in a significant improvement in the compressive strength of the CSD cement prepared by mixing CSH powders with water.
The phase and morphology of the prepared calcium sulfate hemihydrate powders were examined using X-ray diffraction and field emission scanning electron microscopy. The size and average aspect ratio of the powders were measured based on SEM observations. To measure the setting strength of CSD cement, CSH powders were mixed with distilled water at a powder to water weight ratio (P/W) of 2.5 and then poured into a plastic mold and allowed to self-set for 24 h under atmospheric conditions. Samples with a diameter of B8 mm and a height of B16 mm were loaded using a screw-driven load frame at a crosshead speed of 5 mm/min.

Custom Reviews

Semptember 11, 2022

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Great reagent
It's useful for practical problem.

Custom Q&A

What is molecular formula of calcium sulfate hemihydrate?

(CaSO4)2.H2O

What is Canonical SMILES of calcium sulfate hemihydrate?

O.[O-]S(=O)(=O)[O-].[O-]S(=O)(=O)[O-].[Ca+2].[Ca+2]

What is ICSC Number of calcium sulfate hemihydrate?

1217

What is the specific optical rotation of calcium sulfate hemihydrate?

+6.5°(D/20℃

What are the related applications of calcium sulfate hemihydrate?

Calcium sulfate hemihydrate can be used as a diluent for tablets, capsules, fillers, curing agents for slow-release agents, etc. It can also be used in construction as high-strength gypsum components, plasterboard, casting models and mechanical processing of fixed cementitious processing parts and other aspects.

What is the common method of preparation of calcium sulfate hemihydrate?

The most common preparation method of calcium sulfate hemihydrate is the rotary kiln calcination method. Firstly, the raw gypsum is crushed to l~3mm and then added to the indirectly heated rotary kiln for calcination for 15min, and the final temperature of the material is 140~150℃ (115~125℃ for calcined medical gypsum). The clinker was crushed and screened to produce calcium sulfate hemihydrate.

Whether calcium sulfate hemihydrate is toxic to humans?

Dust of calcium sulfate hemihydrate can cause respiratory diseases. The maximum permissible concentration is 2mg/m3. Respiratory organs should be protected at work by wearing work clothes and protective glasses. Observe personal protective measures and pay attention to dust prevention and dust removal in the workplace.

What is the solubility of calcium sulfate hemihydrate in water?

Grams of calcium sulfate hemihydrate dissolved per 100 ml of water at different temperatures:0.223g/0°C;0.244g/10°C;0.255g/20°CChemicalbook;0.264g/30°C;0.265g/40°C0.244g/60°C;0.234g/80°C;0.205g/100

What is the identification of calcium sulfate hemihydrate?

Add 20mL of 2.7 mol/L hydrochloric acid and 80mL of water to 1g of calcium sulfate, shake well and filter, the filtrate shows sulfate reaction and calcium salt reaction.

Calcium sulfate hemihydrate is soluble in which solvents?

Calcium sulfate hemihydrate is soluble in acids, ammonium salts, sodium thiosulfate and glycerol

What are the aliases for calcium sulfate hemihydrate?

Raw Gypsum, Hard Raw Gypsum, Muriacite, Anhydrous Gypsu

What is the melting point of calcium sulfate hemihydrate?

1193℃