Name | Calcium hydroxide |
Synonyms | Slaked lime CARBIDE LIME calcium hydrate Calciumhydroxid8 Calcium Hydroxde dihydroxycalcium Calcium hydroxide calcium dihydroxide CALCIUMHYDROXIDE,TECHNICAL Calcium Hydroxide, Powder, Reagent CALCIUMHYDROXIDE,POWDER,REAGENT,ACS CALCIUMHYDROXIDE,POWDER,USP,EP,BP,JP CALCIUMHYDROXIDE,TECH(HYDRATEDLIM)(BULK |
CAS | 1305-62-0 |
EINECS | 215-137-3 |
InChI | InChI=1/Ca.2H2O/h;2*1H2/q+2;;/p-2/rCaH2O2/c2-1-3/h2-3H |
Molecular Formula | CaH2O2 |
Molar Mass | 74.09 |
Density | 2.24 g/mL at 25 °C (lit.) |
Melting Point | 580 °C |
Boling Point | 2850 °C |
Water Solubility | 1.65 g/L (20 ºC) |
Solubility | 1.7g/l |
Appearance | White powder |
Color | White |
Odor | Odorless |
Exposure Limit | ACGIH: TWA 5 mg/m3OSHA: TWA 15 mg/m3; TWA 5 mg/m3NIOSH: TWA 5 mg/m3 |
Solubility Product Constant(Ksp) | pKsp: 5.26 |
Merck | 14,1673 |
pKa | 12.6[at 20 ℃] |
PH | 11.27(1 mM solution);12.2(10 mM solution);12.46(100 mM solution); |
Storage Condition | Store at +5°C to +30°C. |
Stability | Stable. Incompatible with strong acids. |
Sensitive | Air Sensitive |
MDL | MFCD00010901 |
Physical and Chemical Properties | fine white powder. relative density 2.24 soluble in acid, ammonium salt, glycerol, insoluble in water, insoluble in alcohol. |
Use | Used in the preparation of bleaching powder, hard water softener and tap water Disinfection clarifier and construction industry |
Risk Codes | R41 - Risk of serious damage to eyes R34 - Causes burns R37/38 - Irritating to respiratory system and skin. |
Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S39 - Wear eye / face protection. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S27 - Take off immediately all contaminated clothing. |
UN IDs | 3262 |
WGK Germany | 1 |
RTECS | EW2800000 |
FLUKA BRAND F CODES | 34 |
TSCA | Yes |
HS Code | 2825 90 19 |
Hazard Class | 8 |
Packing Group | III |
Toxicity | LD50 orally in rats: 7.34 g/kg (Smyth) |
white crystalline powder. Tasteless. Usually contains trace amounts of water. d 2. 08~2. 34. Soluble in acid, glycerol, sucrose, ammonium chloride solution, water-soluble, insoluble in ethanol. The pH of the saturated aqueous solution at 25 °c was 12.4. In air, carbon dioxide is readily absorbed into calcium carbonate.
The limestone is calcined into calcium oxide, mixed with water and digested in a certain proportion to obtain calcium hydroxide solution, which is purified and separated to remove impurities and then dehydrated, then, it may be dried at 150 to 300 °c.
Analytical reagents. It is used as an absorbent for acid gases such as carbon dioxide, hard water softener, disinfectant, antacid, buffer, neutralizer, curing agent, etc., and can also be used as an additive for rubber, medicine, and petrochemical products.
rat oral LD50:7340mg/kg. It is a strong alkaline substance with stimulating and corrosive effects. Inhalation of dust, the respiratory tract is strongly irritating, and may cause Pneumonia. Eye contact also has a strong irritation, can cause burns. The maximum allowable concentration is 5mg/m3. Staff should be well protected, if accidentally enter the eyes, should immediately rinse with water. Store in a cool, dry, well-ventilated warehouse.
pH indicator color change ph range | 12.4 |
NIST chemical information | Information provided by: webbook.nist.gov (external link) |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
solubility in water (g/100ml) | dissolution grams per 100ml of water at different temperatures (℃): 0.189g/0 ℃;0.182g/10 ℃;0.173g/20 ℃;0.16g/30 ℃;0.141g/40 ℃ 0.121g/60 ℃;8.6 × 10-2/80 ℃;7.6 × 10-2/90 ℃ |
identification test | mix the sample with 3-4 times the amount of water to form a uniform paste. after standing for clarification, its transparent supernatant is alkaline to litmus. 1g of sample was mixed with 20ml of water, enough acetic acid was added to form a solution, and the calcium salt test (IT-10) was positive. |
content analysis | accurately weigh about 1.5g of sample, move into a beaker, and gradually add 30ml of dilute hydrochloric acid test solution (TS-117). After being completely dissolved, move into a 500ml volumetric flask, thoroughly rinse the beaker, incorporate the lotion into the volumetric flask, dilute with water to scale, and mix well. Take 50.0ml of this solution into an appropriate container and add 50.0ml of water. Under stirring (preferably with a magnetic stirrer), add about 30ml of 0.05mol/L EDTA disodium through a 50ml burette, add 15ml of sodium hydroxide test solution (TS-224) and 300mg of hydroxynaphthol blue indicator, and continue titration to the blue end point. 0.05 mo1/L EDTA disodium per mL is equivalent to 3.705mg of calcium hydroxide. |
toxicity | ADI is not restricted (FAO/WHO,2001). LD507300mg/kg (mouse, oral). It is corrosive and weaker than quicklime. GRAS (FDA,§ 182.1205,§ 184.1205,2000). Its dust or suspension drops have a stimulating effect on the mucosa, can cause sneezing and coughing, and alkali can make fat saponification, absorb water from the skin, dissolve protein, stimulate and corrode tissues. Inhalation of lime dust may cause pneumonia. The maximum allowable concentration is 5 mg/m3. When inhaling dust, water vapor, codeine and Juonen can be inhaled, and mustard cream can be applied to the thorax. When falling into the eye, rinse with running water as soon as possible, then rinse with 5% ammonium chloride solution or 0.01% CaNa2-EDTA solution, and then drip 0.5% dicaine solution. Attention should be paid to the protection of respiratory organs at work, wearing work clothes, gloves and airtight dust-proof glasses made of dust-proof fibers, and applying ointment containing grease to prevent dust inhalation. |
usage limit | GB 2760-96: processing aid, GMP. FAO/WHO(1984): Cream and whey cream, 2 g/kg (only used to adjust Ph value, based on anhydrous); Grape juice and its thick juice (preservative by physical method), preparation of baby food, consumption of caseinate, GMP. The maximum dosage stipulated in Japan is 1.84% (calcium 1%). |
Use | Used in the preparation of bleaching powder, hard water softener, tap water disinfection and clarification agent, construction industry, etc. Used in pharmaceuticals. It can be used as an additive in rubber and petroleum industry, and can be used in lubricating oil to prevent coking, sludge deposition, neutralization and corrosion prevention. It can also be used as hard water softener, disinfectant, acid making agent, etc. used as analytical reagent, carbon dioxide absorbent, also used in organic synthesis used to make bleaching powder, hard water softener, depilating agent, disinfectant, acid stopping agent, astringent and various calcium salts test carbon dioxide, gas absorption. Leather hair removal, insecticidal, water treatment. |
production method | lime digestion method calcined limestone into calcium oxide, digested with water according to the ratio of 1:(3~3.5), the generated calcium hydroxide feed liquid is purified, separated and descaled, then centrifuged and dehydrated, dried at 150~300 ℃, and then screened (above 120 mesh) as calcium hydroxide finished product. Its CaCO3 → CaO CO2 ↑ CaO H2O → Ca(OH)2 |
category | pesticide |
toxicity classification | low toxicity |
acute toxicity | oral-rat LD50: 7340 mg/kg; Oral-mouse LD50: 7300 mg/kg |
stimulation data | eye-rabbit 10 mg severe |
flammability hazard characteristics | non-combustible, but pollution dust |
storage and transportation characteristics | warehouse low temperature ventilation and drying |
fire extinguishing agent | water, carbon dioxide, foam, dry powder |
occupational standard | TWA 5 mg/m3 |
toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |