Potassium carbonate

chemical compound

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Potassium carbonate is an inorganic substance with chemical formula K two CO three , molecular weight 138.206, white crystalline powder, density 2.428g/cm three , melting point 891 ℃. Easily soluble in water, the aqueous solution is alkalinity , insoluble in ethanol 、 acetone and Ether 。 Hygroscopicity Strong, can absorb when exposed to air carbon dioxide And moisture, converted into Potassium bicarbonate , should be sealed.

Chinese name: Potassium carbonate^[2]
Foreign name: Potassium carbonate^[2]
Alias: Potash
chemical formula: K two CO three
molecular weight: one hundred and thirty-eight point two zero six^[2]
CAS login number: 584-08-7^[2]
EINECS login number: 209-529-3^[2]
Melting point: 891 ℃^[2]

Water solubility: Easily soluble in water
Density: 2.428 g/cm³
Appearance: White crystalline powder
Application: Pasta products
Security description: S26；S36；S37/39^[2]
Hazard symbol: Xn^[2]
Hazard description: R22；R36/37/38^[2]
UN dangerous goods number: three thousand two hundred and sixty-two^[2]
Regulatory information: This product is not controlled by the public security department

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Physical and chemical properties

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Density: 2.428g/cm three

Melting point: 891 ℃

PSA：63.19000

Appearance: white crystalline powder

Solubility: easily soluble in water, and the aqueous solution is alkalinity , insoluble in ethanol 、 acetone and Ether

Calculate chemical data

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1. Reference value for drainage parameter calculation (XlogP): None

2. Number of hydrogen bond donors: 0^[2]

3. Number of hydrogen bond receptors: 3^[2]

4. Number of rotatable chemical bonds: 0^[2]

5. Number of tautomers: 0

6. Topological molecular polar surface area: 63.2^[2]

7. Number of heavy atoms: 6^[2]

8. Surface charge: 0^[2]

9. Complexity: 18.8^[2]

10. Number of isotope atoms: 0^[2]

11. Determine the number of atomic structure centers: 0^[2]

12. Number of uncertain atomic structure centers: 0^[2]

13. Determine the number of chemical bond structure centers: 0^[2]

14. Number of uncertain chemical bond structure centers: 0^[2]

15. Number of covalent bond units: 3^[2]

toxicity

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Rat oral LD fifty 1870mg/kg^[1] 。

solubility

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Solubility of potassium carbonate in water
temperature	zero	ten	twenty	thirty	forty	sixty	eighty	one hundred
solubility	one hundred and seven	one hundred and nine	one hundred and ten	one hundred and fourteen	one hundred and seventeen	one hundred and twenty-six	one hundred and thirty-nine	one hundred and fifty-six

Preparation method

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Production methods of potassium carbonate: the production of potassium carbonate includes plant ash method, Lubran method, electrolysis method, ion exchange method, etc. Electrolysis and ion exchange are commonly used.

Vegetation ash method

The plant ash method is the oldest method, which is to extract plant ash from various plant shells (such as cottonseed shells, tea seed shells, tung seed shells, sunflower seed shells). The plant ash contains soluble salts such as potassium carbonate, potassium sulfate and potassium chloride, which can be separated by precipitation and filtration. This method is seldom used due to low product quality, uneconomic and limited raw material sources. The Lubran process is to mix potassium sulfate with coal powder and lime, reduce and roast to obtain black ash (containing calcined products such as potassium carbonate and calcium sulfide), leach, filter, evaporate and carbonize to obtain potassium bicarbonate, and then filter and calcine to obtain products. This method has been replaced by other methods due to long process flow and other reasons.

Electrolytic method

Electrolysis of potassium chloride Potassium hydroxide Solution, in the carbonization tower carbon dioxide Carbonization. through Multi effect evaporator The potassium bicarbonate is obtained by evaporation and filtration, and then calcined to obtain the product. This method is widely used because of the easy availability of raw materials, high potassium utilization rate and no production of three wastes, but it consumes more electricity.

Ion exchange method

use cation exchange resin Exchange with potassium chloride. Reuse Ammonium bicarbonate The product is eluted into a dilute solution of potassium bicarbonate, and is obtained through multiple effect evaporation, carbonization, crystallization, separation and calcination. This method has good product quality, short process flow and is suitable for small-scale production.

Identification test

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The potassium test (IT-27) and carbonate test (IT-11) of 10% sample solution were positive.

Content analysis

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In a weighed weighing bottle with a stopper, accurately weigh 1g of the dry sample obtained according to the "loss on drying" method, and dissolve it in 50mL of water. Add 2 drops of methyl red test solution (TS-149), and slowly titrate with 1mol/L hydrochloric acid under constant agitation until the solution turns pale pink. Heat the solution until it boils down and cools down. Continue titration until the light pink color no longer disappears after boiling. 1mol/L hydrochloric acid per milliliter is equivalent to potassium carbonate (K two CO three ）69.10mg。

Quality index analysis:

1. Arsenic: Take 1g of sample, carefully dissolve it in about 5mL of dilute hydrochloric acid test solution (TS-117), take it as the sample solution, and determine it according to GT-3 method.

2. Heavy metals: Take 1g of sample, add 2mL of water and 6mL of dilute hydrochloric acid test solution (TS-117), boil for 1min, and dilute with water to 25mL. Take this as the sample solution and determine it according to GT-16 method. Use the control solution (solution A) containing 20 μ g lead ion.

3. Water insoluble substance: take 1g sample and dissolve it in 20mL water, and there should be no residue left.

4. Lead: Take 1g of sample, carefully dissolve it in 5mL of dilute hydrochloric acid test solution, and use it as the sample solution. Determine according to GT-18 method: take 10 μ g of lead ion in the control solution.

5. Loss on drying: accurately weigh about 3g of the sample and measure it according to GT-19 method. The condition is drying at 180 ℃ for 4h.

ACS level

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Project name: ACS Grade (American Chemical Society Grade)

Project (Chinese)	Project (foreign language)	result
Content (K two CO three )	Assay	≥99.0%
Water insoluble substance	Insoluble matter	≤0.01%
Chloride (Cl)	Chloride	≤0.003%
Phosphate (PO four )	Phosphate	≤0.001%
Silica (as SiO two Count)	Silica	≤0.005%
Sulfur compounds (as SO four Count)	Sulfur compounds	≤0.004%
Heavy metals (in Pb)	Heavy metals	≤5ppm
Iron (Fe)	Iron	≤5ppm
Calcium (Ca)	Calcium	≤0.005%
Magnesium	Magnesium	≤0.002%
Sodium	Sodium	≤0.02%
Reference reagent		PT
purity	Assay	99.95-100.05%
keep in storage		Sealed and dry storage

Purity standard

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Item	Superior pure (GR)	Analytical reagent (AR)	Chemically pure (CP)
Content (K two CO three ）：Assay%≥	ninety-nine point five	ninety-nine	ninety-eight
Clarity test	qualified	qualified	qualified
Loss on drying,% ≤	zero point eight	one	two
Insoluble matter in water,% ≤	zero point zero zero five	zero point zero zero five	zero point zero three
Chloride,% ≤	zero point zero zero one	zero point zero zero three	zero point zero one
Sulfur compound Sulfur compounds，% ≤	zero point zero zero three	zero point zero zero two	zero point zero one
Total nitrogen,% ≤	zero point zero zero one	zero point zero zero one	zero point zero one
phosphate and silicate Phosphate and silicate，% ≤	zero point zero zero four	zero point zero zero five	zero point zero two
Sodium,% ≤	zero point zero two	zero point zero five	zero point one zero
Calcium,% ≤	zero point zero zero two	zero point zero two	zero point zero two
Magnesium,% ≤	zero point zero zero zero five	zero point zero zero two	zero point zero zero five
Aluminum,% ≤	zero point zero zero five	zero point zero zero five	zero point zero zero five
Iron,% ≤	zero point zero zero zero five	zero point zero zero zero five	zero point zero zero two
Lead,% ≤	zero point zero zero zero five	zero point zero zero zero five	zero point zero zero one
Copper,% ≤	zero point zero zero zero five	zero point zero zero zero five	zero point zero zero one
Arsenic,% ≤	zero point zero zero zero zero five	zero point zero zero zero zero five	zero point zero zero zero zero five

application area

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Inorganic industry for manufacturing Potassium sodium tartrate , potassium aluminofluorate Potassium thiocyanate 、 Titanium dioxide 。 Pharmaceutical industry for manufacturing Long-acting sulfa 、 progesterone 、 Cortisone , Zhiakor Estradiol benzoate Etc. The glass enamel industry is used for the preparation of enamel powder to enhance its leveling property, add it into the glass to play the role of melting aid, and improve the transparency and refractive coefficient of the glass. Dye industry is used to manufacture Yindan earth forest Disperse red 3B 、 Restore Grey M Etc. The printing and dyeing industry is used for the printing and dyeing of vat dyes and the white discharge of ice dyeing. The rubber industry is used to manufacture 4010 antioxidant. The wool, linen and cotton industry is used for boiling cotton cloth and degreasing wool.

Potassium carbonate is one of the important basic inorganic chemical, pharmaceutical and light industrial raw materials. It is mainly used in the production of optical glass, welding electrodes, electronic tubes, television picture tubes, light bulbs, printing and dyeing, dyes, inks, photographic drugs, sodamine, polyester, explosives, electroplating, tanning, ceramics, building materials, crystals, potassium soap and drugs. Used as gas adsorbent, dry powder extinguishing agent, rubber antioxidant. It is also used to remove carbon dioxide from fertilizer synthesis gas. It can also be used as potassium fertilizer. With the continuous development of high-tech, the application of potassium carbonate in the fields of detergent additives, monosodium glutamate, food, etc. is also expanding.

Potassium carbonate is mainly used for manufacturing potassium glass, potassium soap and other inorganic chemicals, as well as for removing hydrogen sulfide and carbon dioxide from industrial gases, and also for welding electrodes, ink manufacturing, printing and dyeing industries, etc.

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