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Send EmailCalcium Carbonate, Akadama, PARIS WHITE, PRECIPITATED CHALK, Oyster Shell Powder, 471-34-1, 13397-25-6, 1317-65-3, C.I. 77220, Pigment White 18, Weightily Calcium Carbonate, Biological Calcium Carbonate
CAS Numbers: 471-34-1; 13397-25-6; 1317-65-3
Molecular Formula: CCaO3
Names and Identifiers
| Name | Calcium carbonate |
| Synonyms | Chalk akadama albacar albafil albaglos aeromatt Limestone C.I. 77220 albacar5970 PARIS WHITE Calcium carbonate PRECIPITATED CHALK Oyster Shell Powder C.I. Pigment White 18 Calcium Carbonate Light Calcium Carbonate Heavy Weightily Calcium Carbonate Biological Calcium Carbonate |
| CAS | 471-34-1 13397-25-6 1317-65-3 |
| EINECS | 207-439-9 |
| InChI | InChI=1/CH2O3.Ca.2H/c2-1(3)4;;;/h(H2,2,3,4);;;/p-2/rCH2O3.CaH2/c2-1(3)4;/h(H2,2,3,4);1H2/p-2 |
| InChIKey | VTYYLEPIZMXCLO-UHFFFAOYSA-L |
Physico-chemical Properties
| Molecular Formula | CCaO3 |
| Molar Mass | 100.0869 |
| Density | 2.93 g/mL at 25 °C (lit.) |
| Melting Point | 825 °C |
| Boling Point | 800 °C |
| Water Solubility | Insoluble |
| Solubility | 5 M HCl: 0.1M at20°C, clear, colorless |
| Appearance | White powder |
| Specific Gravity | 2.93 |
| Color | White-beige to slightly beige-gray |
| Odor | Odorless |
| Exposure Limit | NIOSH: TWA 10 mg/m3; TWA 5 mg/m3 |
| Solubility Product Constant(Ksp) | pKsp: 8.54 |
| Maximum wavelength(λmax) | ['λ: 260 nm Amax: ≤0.09', , 'λ: 280 nm Amax: ≤0.06'] |
| Merck | 14,1657 |
| BRN | 8008338 |
| PH | 9.91(1 mM solution);9.91(10 mM solution);9.91(100 mM solution); |
| Storage Condition | Store at +5°C to +30°C. |
| Stability | Stable. Incompatible with acids, fluorine, ammonium salts, alum. |
| Sensitive | Easily absorbing moisture |
| Refractive Index | 1.6583 |
| MDL | MFCD00010906 |
| Physical and Chemical Properties | Appearance and properties: odorless, tasteless white powder or colorless crystals. melting point (℃): 825 (decomposition) boiling point (℃): No data relative density (water = 1): 2.70-2.95 solubility: insoluble in water, soluble in acid. white powder, tasteless, odorless. There are two kinds of morphology: stereotyped and crystalline. The crystal type can be divided into orthorhombic crystal system and hexagonal system, which is columnar or diamond-shaped. The relative density was 2.71. 825~896.6 degrees C decomposition, melting point of 1339 degrees C, 10.7MPa melting point of 1289. Difficult to dissolve in water and alcohol. Soluble in acid, while releasing carbon dioxide, exothermic reaction. Also soluble in ammonium chloride solution. Stable in air, with slight moisture absorption. Have better hiding power. |
| Use | For the preparation of cement, ceramics, lime, calcium salt, toothpaste, dyes, pigments, mineral water, artificial stone, putty, neutralizers, catalysts, fillers, pharmaceuticals. it can be used as a filler in rubber, plastic, paper, putty, primer, coating and ink industries. Widely used in organic synthesis, metallurgy, glass and asbestos production. It can also be used as a neutralizing agent for industrial wastewater, an antacid agent for gastric and duodenal ulcer disease, an antidote for acidosis, a sulfur dioxide removing agent for sulfur dioxide in sulfur dioxide-containing waste gas, a dairy feed additive, and an anti-sticking agent for wool felt, etc. It can also be used as a raw material for tooth powder, toothpaste and other cosmetics. |
Risk and Safety
| Hazard Symbols | Xi - Irritant |
| Risk Codes | R37/38 - Irritating to respiratory system and skin. R41 - Risk of serious damage to eyes R36/38 - Irritating to eyes and skin. R36 - Irritating to the eyes |
| Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S37/39 - Wear suitable gloves and eye/face protection S37 - Wear suitable gloves. |
| UN IDs | N/A |
| WGK Germany | - |
| RTECS | FF9335000 |
| TSCA | Yes |
| HS Code | 28365000 |
| Toxicity | LD50 orally in Rabbit: 6450 mg/kg LD50 dermal Rat > 2000 mg/kg |
Upstream Downstream Industry
| Raw Materials | Ammonium chloride Calcium carbonate |
| Downstream Products | Calcium perphosphate,ammonified,granular Calcium Formate |
Nature
white crystalline powder. Odorless and tasteless. There are two kinds of crystals, one is the orthogonal crystal aragonite. d 2. 83, melting point 825 ℃ (decomposition), decomposition of calcium oxide and carbon dioxide. One is the hexagonal rhombohedral crystal calcite, d25.2 711, melting point 1339 ℃(10. 39MPa). Practically insoluble in water, soluble in acid.
Preparation Method
calcium hydroxide reacts with hydrochloric acid to obtain calcium chloride, which is decolorized by activated carbon and filtered to remove impurities, so that calcium chloride is carbonized with carbon dioxide in the presence of ammonia water to obtain calcium carbonate, which is then crystallized, separated, washed, dehydration, drying to obtain pure calcium carbonate.
Introduction
No smell. Tasteless. Decompose into calcium oxide and carbon dioxide at 825 ℃. Soluble in dilute acid and release carbon dioxide, insoluble in alcohol. There are two kinds of crystals, one is orthorhombic artefact and the other is hexarhombic calcite. Calcite, pungent.
Use
reagents for the assay and determination of halogens in organic synthesis reactions and for the assay of phosphorus. Used for silicon single crystal chip glue, thick film capacitor material and manufacturing optical neodymium glass raw material.
Safety
Open Data Verified Data
rat oral LDso:6450mg/kg. It has a strong stimulating effect on the eyes and a moderate stimulating effect on the skin. Store in a cool, ventilated warehouse. Should be stored separately from acids, ammonium salts, etc. No impact, tumbling or falling during handling. Attention should be paid to personal protection in sub-packing and handling operations.
Reference Information
| update date: | 2022/11/12 12:49:22 |
| pH indicator color change ph range | 8 |
| application | in recent years, with the rapid development of China's rubber industry, the amount of calcium carbonate has been continuously increasing. 1) tires: light calcium carbonate and nano calcium carbonate often partially replace low-structure carbon black and white carbon black for tire rubber (dosage exceeds 70 parts) and inner tire rubber, automobile tire carcass ply rubber, airtight layer rubber, inner lining rubber and inner tire rubber to reduce production costs. In addition, the use of nano-calcium carbonate and ultra-fine active zinc oxide to replace ordinary zinc oxide can improve the tensile strength, elongation at break, flex resistance and fatigue resistance of car tire tread rubber. 2) Hose and Tape: Light calcium carbonate and nano calcium carbonate are used in hoses and tapes. One is to play the role of white reinforcing filler, and the other is to improve the dispersibility of the rubber. Calcium carbonate can be used in rubber hose for ordinary rubber hose, color rubber hose, hydraulic rubber hose and short fiber reinforcement rubber hose, etc., in the adhesive tape can be used for conveyor belt, transmission belt and synchronous belt, etc. 3) rubber shoes: calcium carbonate can adapt to different color requirements, and can improve the mixing and extrusion properties of rubber materials. it is widely used in rubber shoes, and is often used in the upper, sole and heel of rubber shoes with carbon black, white carbon black, titanium dioxide and clay. 4) wires and cables: calcium carbonate is generally used as reinforcing filler for sheaths such as mine wires and cables, marine wires and cables, high-voltage wires and cables, and rubber materials for electrical wires and cables. In wire and cable compounds containing chlorine rubber, such as CR, chlorinated polyethylene rubber (CM) and chlorinated cis-polybutadiene rubber, calcium carbonate not only acts as a reinforcing filler, but also reduces the acidity of the compound and absorbs hydrogen chloride generated during the processing of the compound, thus avoiding the effect of delayed vulcanization and return of the compound, and improving the extrusion performance of the compound. |
| activated calcium carbonate | activated calcium carbonate is mainly used as a reinforcing agent for rubber, plastics, etc., which can improve the tensile strength and wear resistance of products, make foamed rubber foam evenly, and can also be used as a filler for inks and coatings. calcium carbonate powder is an important inorganic chemical product, which is widely used in rubber, plastic, paint, papermaking, food, cosmetics, medicine and daily chemical industries. Because the surface of calcium carbonate has many water hydroxyl groups, the surface is hydrophilic and oleophobic, it is easy to form aggregates, and the dispersion performance is poor, which directly affects the application. For example, when calcium carbonate is used in polymers or rubber products, it cannot be chemically combined with polymers, which is difficult to strengthen, but can only increase compatibility. Therefore, the filling of calcium carbonate will cause some properties of the polymer to decrease, especially excessive filling, which will cause a sharp decline in the properties of the polymer, so that the product cannot be used. In order for the calcium carbonate powder to have the required properties, a surface treatment agent can be adsorbed or reacted on the surface of the calcium carbonate powder by physical or chemical methods to form a surface modification layer to activate the surface, thereby improving the binding force with high polymers or other materials. In addition, when activated modified calcium carbonate is used as a filler, the dispersibility and fluidity are improved, the phenomenon of agglomeration and agglomeration is avoided, and the appearance quality of the product surface is significantly improved. the active modification of calcium carbonate can be mainly divided into wet surface treatment and dry surface treatment. When wet surface treatment is used to produce light calcium carbonate or ultra-fine calcium carbonate by carbonization method, molten surface treatment agent is added before or after carbonization. Dry surface treatment is to put the finished calcium carbonate into a kneader and add a coupling agent for surface coating. This product is based on light calcium carbonate as raw material, and the active calcium carbonate is prepared by dry treatment. It has the characteristics of simple and feasible treatment method. The obtained product has a broad market in plastics, rubber, papermaking, food and medicine industries. |
| solubility in water (g/100ml) | dissolved grams per 100ml of water: 6.170 × 10-4/20 ℃ |
| content analysis | preparation of calcium reagent weigh 10g of analytically pure sodium chloride prebaked at 105~110 ℃ for 2h, grind it in a mortar, weigh 0.1g of calcium reagent (chrome blue ink r), and mix it with sodium chloride in the same mortar. Stored in brown bottles. For measurement, weigh 0.5g of sample baked at 110~120 ℃ to constant weight (weighing to 0.0002g), place it in a 100ml high beaker, moisten it with a small amount of water to remove carbon dioxide, cover it with a surface dish, gradually add 1:1 hydrochloric acid solution dropwise until it is completely dissolved, dilute with water, transfer it to a 250ml volumetric flask, dilute with water to scale, and shake well. Absorb 25ml into a 250ml conical flask and add 5mI. 30% triethanolamine solution, 25ml of water and 5mI. 10% sodium hydroxide solution to make the pH of the solution ≥ 12, add a small amount of solid calcium reagent, titrate with 0.02mol/L EDTA standard solution, and the solution changes from red to purple to pure blue. Calcium carbonate (%)= V? C × 0.1001/G × 25/250 × 100 Volume of EDTA standard solution consumed by V-titration, ml; C -- concentration of EDTA standard solution, mol/L;G -- sample quantity, g;0.1001 -- millimolar amount of calcium carbonate, g. |
| toxicity | ADI is not restricted (FAO/WHO,2001). GRAS(FDA ,§. 184.1191,§ 182.5191,2000). LD50 6450mg/kg (rat, oral). GRAS(FDA § 184.1191;§ 182.5191:2000). See activated calcium carbonate. See heavy calcium carbonate. Long-term suction of limestone dust, often the upper respiratory tract of atrophic catarrh, bronchitis, accompanied by emphysema, crushing workers can see diffuse-hardened pneumoconiosis. The maximum allowable concentration of limestone dust is 6 mg/m3, and the allowable concentration of marble dust in the United States is 10 mg/m3. Pay attention to protect respiratory organs and skin when working, wear masks, gloves, work clothes, to prevent people from sucking dust. |
| usage limit | GB 14880-94: cereals and their products and beverages 4~8 g/kg; Fortified milk beverage 0.52 g/kg (fortified amount based on elemental calcium: cereals and their products and beverages 1.6~3.2 g/kg; Infant food 3.0~6.0 g/kg). GB 2760-2001: light calcium carbonate can be used for all kinds of food and gum gum base that need to add leavening agent, according to GMP. Can also be used as flour improver, 0.03% (in flour); Milk powder 7.5~18 g/kg. Soybean milk powder, soybean powder, 4~20 g/kg; Soft drinks 0.4~3.4 g/kg; Lotus root starch 6~8 g/k; Instant breakfast cereal products, 2~7g/kgGB 14880-94 (calculated as Ca; G/kg); Beverages, 1.6~3.2; Cereals and their products, 1.6~3.2; Infant food, 3.0~6.0 (calcium carbonate containing calcium 40%). FDA § 184.1191(2000): No Restrictive Provisions, GMP. BATF,27CFR,§ 240.1051(2000): Wine, 13.62kg/3785L. FAO/WHO(1984): cocoa powder, sugar-containing cocoa powder, cocoa bean powder, cocoa liquid mass and cocoa oil cake, 5 g/kg (based on fat-free cocoa, calculated by K2CO3); 40 g/kg of processed cheese (calculated by anhydrous); Concentrated fruit juice, baby and children's cereal food (according to GMP) that are only preserved by physical methods; Low-power concentrated milk, sweetened condensed milk and thin cream (2 g/kg alone, 3 g/kg combined with other stabilizers; In terms of anhydrous); Milk powder and cream powder 5 g/kg (in terms of anhydrous); Jam and jelly 200 mg/kg (in terms of Ca). It can also be used as a calcium fortifier for bread (0.25%), confectionery products, baby food (milk replacement powder, etc.), noodles, dairy products, table salt, fish cake, sausage, spices, etc. Hardener for brewing water, deacidifier for wine, neutralizer for caramel. Mix with salt for pickles. Used in ice cream making and acid making glucose. When using polyphosphate as quality improver in minced meat products, it is best to add calcium to balance calcium and phosphorus (the addition amount is 0.5% ~ 1.5%, calculated as calcium). 5% ~ 10% is added to the vinyl acetate base of gum. When making wine, calcium carbonate (or potassium carbonate) can be used to remove some acid from fruit juice with high acidity (above 1.5%). For every 100L grape juice to remove 0.1% acid, 66g calcium carbonate is required. Acid can be removed after fermentation. The compound leavening agent can also add appropriate amount of calcium carbonate. Prevent hard candy from consolidating. Promote crystallization of milk chocolate with 2.4% dosage. Japan's highest usage (in terms of calcium): general food l%, gum sugar 2%. It is easy to work with acid, alum and ammonium salt, so attention should be paid. |
| use | used to improve the flex resistance of polyvinyl chloride soft products, it is also widely used in rubber, adhesives and sealants as fillers and reinforcing agents used as analytical reagents, reference reagents, silicon single crystal slicing adhesives and thick film capacitor materials Mainly used as rubber, plastics, and coatings industry Filling and reinforcing materials Used to produce cement, ceramics, lime, carbon dioxide, chalk, artificial stone, putty, and used as pigment, neutralizing agent, polishing agent, plastic and rubber filler used as filler for rubber, wire, artificial leather, paint, ink, paper, etc. used to make cement, ceramics, Lime, calcium salt, toothpaste, dye, pigment, mineral water, artificial stone, putty, neutralizing agent, catalyst, filler, medicine, etc. used as filler for plastics, rubber and coatings used to produce anhydrous calcium chloride, sodium dichromate, glass, cement, building materials, etc. used as filler, extender and reinforcing agent in rubber, plastic, ink, paint, paper making and daily chemical industries can replace part of semi-reinforced carbon black as rubber reinforcing agent, it is also used in papermaking, plastics, paints, etc. It is mainly used as a filler in rubber, plastics, papermaking, coatings, inks and other industries, and can be used in dental powder, toothpaste, cosmetics and other daily chemical products Used in papermaking, water-soluble latex paint, plastic filling modification, etc. It is a rubber filler, which can make the rubber bright in color, high in elongation, high in tensile strength and good in wear resistance. It is also used as a filler for artificial leather, wire, polyvinyl chloride, paint, ink and paper industry. When it is used to produce microporous L rubber, it can be foamed evenly. in the pharmaceutical industry, it is used as medicine filling, calcium supplement, etc. in the food processing, it is used as loosening agent, starter and nutritional calcium supplement in the fields of rubber, plastic, paper making, building materials, medicine and food widely used in the plastic, rubber, paint, paper making and other industries, used as filler and reinforcing agent used as filler for making calcium carbonate and other chemical raw materials and filler for rubber, paint, etc. used as filler for papermaking and plastic as chemical leavening agent, which can be used in all kinds of food that need to add leavening agent according to the regulations of our country, and should be used appropriately according to the production requirements; As a flour improver, used in flour, the maximum usage is 0.03 g/kg. Used in rubber, it can effectively improve the compressive strength, abrasion resistance and extrusion strength of rubber products; used in plastic products to make the surface of the product smooth and smooth, instead of part of the PVC resin content; used in paper Making, it can improve the gloss, whiteness and opacity of coated paper, improve the printability of paper, and is widely used in matting paper, charcoal-free carbon paper, paper quantitative coated paper, white cardboard, etc. As a feed nutrition fortifier. According to the fineness of crushing, the industry is divided into four different specifications: solo, double-flying, three-flying, and four-flying, which are used in each industrial sector. Single fly powder is used to produce anhydrous calcium chloride. It is an auxiliary raw material for the production of sodium dichromate and the main raw material for the production of glass and cement. In addition, it is also used for building materials and poultry feed; double fly powder is the production of anhydrous calcium chloride The raw material for glass and glass is also a white filler for rubber and paint, and is also used for building materials; three fly powder can be used as a filler for plastics, coatings and paints; sifei powder can be used as filler for wire insulation, rubber molded products and asphalt linoleum. As a calcium nutrition enhancer, it has better absorption effect than calcium carbonate. Our country stipulates that it can be used for infant food, and the usage amount is 7.5~15 g/kg; 4~8 g/kg in cereals and their products; It is 1~2 g/kg in drinking liquid and milk beverage. It can be used as a filler for rubber, plastic, paper, putty, primer, paint and ink industries. Widely used in organic synthesis, metallurgy, glass and asbestos production. It can also be used as a neutralizer for industrial wastewater, an acid-making agent for gastric and duodenal ulcer disease, an antidote for acidosis, a sulfur dioxide elimination agent in sulfur dioxide exhaust gas, a dairy cow feed additive and an anti-sticking agent for felt, etc. It can also be used as raw materials for tooth powder, toothpaste and other cosmetics. Used in toothpaste, medicine, etc. It can also be used as thermal insulation materials and other chemical raw materials. Calcium fortifier. It can be used as a filler in rubber, plastic, paper, paint and ink industries. Widely used in organic synthesis, metallurgy, glass and asbestos production. It can also be used as a neutralizer for industrial wastewater, an acid-making agent for gastric and duodenal ulcer disease, an antidote for acidosis, a sulfur dioxide elimination agent in sulfur dioxide exhaust gas, a dairy cow feed additive and an anti-sticking agent for felt, etc. It can also be used as raw materials for tooth powder, toothpaste and other cosmetics. Used as filler, used in welding electrodes, organic synthesis, metallurgy, glass, asbestos, medicine, daily chemical industry and other departments. |
| production method | carbonization method breaks the selected limestone to 50-150mm, and the particle size of smokeless (white) coal is 38-50mm. Coal and limestone are put into the furnace at a ratio of 1:8 to 1:11 and calcined at 900 to 1100 ℃ to decompose limestone into quicklime and carbon dioxide at high temperature. With 3~5 times of water, digestion and dissolution at 90 ℃ for 1.5~2.0h to obtain lime milk with a concentration of 10~18 ° Bé, which is filtered to remove impurities and carbonized. After washing and purification, carbon dioxide is sent to the carbonization tower with a concentration of 30% ~ 40%, a carbonization temperature of 60~70 ℃, a carbonization pressure of 0.078 Mpa, and a pH value of 7 at the end of carbonization. Calcium carbonate slurry is centrifuged and dehydrated (water content 32% ~ 42%). Drying (moisture content below 0.3%), cooling, crushing and sieving to produce light calcium carbonate finished products. Its CaCO3 → CO2 + CaOCaO + H2O → Ca(OH)2Ca(OH)2 + C02 → CaCO3 + H2O is formed by cleaning, crushing and sieving unsintered biological raw materials such as eggshells, corals, shells, fish bones, pearl layers, etc. calcium chloride carbonization method calcium hydroxide reacts with hydrochloric acid to generate calcium chloride, which is decolorized by activated carbon and filtered to remove impurities, so that calcium chloride is carbonized with carbon dioxide in the presence of ammonia water to obtain calcium carbonate, and then crystallized, separated, washed, dehydrated, dried and screened to obtain finished crystalline calcium carbonate. Its Ca(OH)2 + 2HCl → CaCl2 +2H2OCaCl2+2NH3 · H2O + CO2 → CaCO3 + 2NH4Cl + H2O carbonization method. The operation method of CaCO3 → CO2 + CaO + H2O → Ca(OH)2 Ca(OH)2 + CO2 → CaCO3 + H2O is: the selected limestone is broken to 50 ~ 150mm, and the particle size of smokeless (white) coal is 38 ~ 50mm. Coal and limestone are put into the furnace at a ratio of 1:8 to 1:11 and calcined at 900 to 1100 ℃ to decompose limestone into quicklime and carbon dioxide at high temperature. With 3~5 times of water, quicklime is digested and dissolved at 90 ℃ for 1.5~2 hours to obtain lime milk with a density of 1.075~1.143g/cm3, which is filtered out and carbonized. After washing and purification, carbon dioxide is sent to the carbonization tower with a concentration of 30% ~ 40 yuan, a carbonization temperature of 60~70 ℃, a carbonization pressure of 0.078MPa, and a pH value of 7 at the end of carbonization. Calcium carbonate slurry is centrifugally dehydrated (water content 32% ~ 42%). Drying (moisture content below 0.3%), cooling, crushing and sieving to produce light calcium carbonate products. The product is obtained by cleaning, crushing, sieving and other refined biological raw materials such as eggshells. the crushing method first crushes white stone (natural limestone) in the jaw crusher to make its block degree reach 40 -- 60mm, and then lifts it to Raymond crusher with a hoist for crushing. Blowing the crushed semi-finished products to the cyclone classifier with a blower for classification. The coarse product is returned to the crusher for reprocessing. Qualified products are separated by cyclone separator to obtain products. limestone (containing more than 98% calcium carbonate) is used as raw material, which is prepared by calcination, digestion and CO2 carbonation: limestone crushed to 50-150mm is mixed with coke (30-50mm) in a ratio of 1:10, and then calcined in a lime kiln at a high temperature (1000-1100 ℃) to obtain quicklime. Quicklime is digested with 3-5 times of hot water at 60-80 ℃ for 1h, and the obtained lime milk is removed from slag and filtered to obtain lime milk with a relative density of 1.07-1.11(10-14 Bé). CO2 gas (containing CO 220%-35%) from lime kiln and purified by washing is introduced into lime milk, and calcium carbonate precipitate is precipitated by carbonation at 40-45 ℃. After natural sedimentation for a period of time, the supernatant is removed, and the lower calcium carbonate is centrifuged and dehydrated to obtain a filter cake with water 30% to 37%. The finished product is obtained by drying and crushing. The raw material for wet grinding calcium by grinding method is heavy calcium carbonate or calcite with whiteness> 93 degrees and calcium content> 98% degrees. Ultrafine calcium carbonate is prepared by batching, wet grinding, pressure filtration, drying and packaging. Precipitated limestone is calcined at high temperature to produce calcium oxide and carbon dioxide, and the lime is digested with water to obtain calcium hydroxide. After the lime milk is graded, it reacts with the purified carbon dioxide. During carbonization and crystallization, a crystallization control agent is added to control the crystal form, or an emulsifier is added. And the surface treatment agent makes the active agent and the newly formed fine calcium carbonate particles evenly cover the surface. After carbonization and crystallization, it is centrifugally dehydrated, dried, graded, and packaged to prepare ultra-fine calcium carbonate. The reaction is as follows: CaCO3 → CaO + CO2 ↑ CaO + H2O → Ca(OH)2Ca(OH)2 + CO2 → CaCO3 ↓ + H2OCaCO3 + surface treatment agent → ultrafine calcium carbonate, of which the surface treatment agent is soluble fatty acid glyceride, titanate, aluminate coupling agent, etc. the limestone crushed to 50~150mm is mixed with coke (30~50mm) in a ratio of 1:10, and then calcined at high temperature (1000~1100 ℃) in a lime kiln to obtain quicklime. Quicklime is digested with 3-5 times of hot water at 60-80-C for 1h, and the obtained raw lime milk is obtained by removing slag and filtering to obtain lime milk with relative density of 1.07-1.11(10-14 Bè); CO2 gas (containing CO 220%-35%) from lime kiln and purified after washing is introduced into lime milk, and calcium carbonate precipitates are carbonized at 40-45 ℃. After natural sedimentation for a period of time, the supernatant is analyzed, and the lower calcium carbonate is centrifugally dehydrated to obtain a filter cake with a water content of 30% ~ 37%, and the finished product is obtained after drying and crushing. CaCO3 → CaO + CO2CaO + H2O → Ca(OH)2[CO2] → CaCO3 + H2O Carbonization limestone is calcined at high temperature, digested with water first, then filtered and carbonized to generate calcium carbonate. The slurry is put into a pulp pool and applied slowly under stirring. The sizing amount per ton is 54 kg. Preparation of glue: take 4.5kg of 36 ° éju sodium hydroxide, add 40 kg of water at 70 ℃, and blend into solution I; Another 15 kg of stearic acid and 40 kg of water are added, heated and dissolved, and slowly added into solution I under stirring to generate sodium stearate. Then, add 6kg of ancient oil, adjust the solution to neutral, and add water to a total of 162kg, which can be used for 3 t finished products. When the fat content in the finished product reaches 0.5%, it is dried by natural or ventilation to reduce the moisture content to 10% ~ 15%, dried at 80 ℃ to make the moisture content below 0.5%, and then sieved to produce activated calcium carbonate finished product. Its CaCO3 → CaO + CO2 ↑ CaO + H2O → Ca(OH)2Ca(OH)2 + CO2 → CaCO3 + H2O |
| category | toxic substances |
| toxicity classification | low toxicity |
| acute toxicity | oral-rat LD50: 6450 mg/kg |
| stimulation data | skin-rabbit 500 mg/24 hours moderate; Eye-rabbit 0.75 mg/24 hours severe |
| flammability hazard characteristics | thermal decomposition discharges spicy and irritating smoke |
| storage and transportation characteristics | warehouse low temperature ventilation and drying |
| fire extinguishing agent | water |
