Calcium oxide CaO also known by other names such as calcium, quicklime or calcined lime, is a white, caustic and alkaline crystalline solid that is solid at room temperature. It is a commercial product containing magnesium oxide, silicon oxide, smaller amounts of aluminum oxide and iron oxide, which is widely used in life, especially in the field of metallurgy and environmental treatment. In India before, when soap was not discovered, it was mixed with sand and used to clean the body. So calcium oxide How is it manufactured, and what specific applications are there? . This article will answer those questions for you
Overview of Calcium oxide
What is calcium oxide CaO? Quicklime. Physical and chemical properties
Calcium oxide CaO is also known by other names such as calcium, quicklime or calcined lime.
Molecular Formula | High |
Physical state | crystalline solid |
Color | White |
Nature | It is caustic, alkaline |
Element | In addition to CaO, quicklime also contains impurities such as Magnesium oxide, Silicon oxide, Aluminum oxide, Iron II oxide |
Molar mass | 56.1 g/mol |
Expansion coefficient | 0.148 |
Melting point | 2850oC (3123 K) |
Melting temperature | 2572oC (2845 K) |
Specific gravity | 3.3- 3.4 x 103 kg/m3 |
The solubility | Soluble in water |
Crystal structure | Cubic face center |
Melting temperature | 2572oC (2845 K) |
Calcium oxide is a basic oxide so it has all the properties of a basic oxide.
- Effect with water
CaO + H2O → Ca(OH)2
- React with acids to form salt and water
CaO + 2HCl → CaCl2 + FRIENDS2O
- React with acidic oxides to form salts
CaO + CO2 → CaCO3
The reaction that occurs when quicklime is added to water
CaO + H2O → Ca(OH)2
Calcium oxide production process – Quicklime
Raw materials used to produce quicklime are rocks rich in calcium carbonate minerals, mainly limestone. There are also some other types such as coral stone, dolomite rock (clay content less than 6%).
Quicklime production line
Crush the stone into small balls of uniform size 10-20cm before heating in the oven at a high temperature of 900-1100.oC. The fuel used is firewood, oil, natural gas, etc. The reaction occurs as follows:
Burning coal produces CO2 and give off a lot of heat
C + O2 → CO2
The heat generated decomposes limestone
CaCO3 ↔CAO + CO2 – Q (heat)
This is a reversible reaction. Therefore, if you want to increase the quality of lime, it is necessary to push the forward direction by creating ventilation in the lime kiln so that CO2 exit easily.
Handmade lime kiln
Note:
If the stones to be fired are of irregular size, quicklime and burnt lime are very likely to occur.
- If large stones are heated, calcium carbonate will not completely convert to calcium oxide, causing the finished product to have poor quality, many stones, and less plasticity.
- With small sized stones or too high temperature in the kiln, the generated calcium oxide will react with clay impurities to form a very hard calcium silicate, calcium aluminate colloidal film. They cover the lime particles making it difficult for them to hydrolyze in water, lime absorbs water and absorbs much moisture, increasing the volume, causing the structure to be pitted and cracked.
Criteria for assessing quality of Quicklime
Lime quality depends on calcium oxide content.
Quicklime
The criteria for assessing lime quality:
- The activity of lime: Depends on the content of calcium oxide, magnesium oxide. The larger the amount, the more lime and mortar output and vice versa.
- I temperature (the highest temperature of the curing process) and the curing time (from the time the lime is added to the water to the maximum boiling point): The greater the amount of heat released when slaked, the longer the curing time. The shorter the time, the purer the lime, the higher the calcium oxide content. The output of lime mortar will be much.
- Lime yield: The higher the quantity of lime, the better the quality of lime. They depend on calcium oxide content, temperature, curing time.
- The amount of grit (unhardened lime in lime mortar): The amount of grit is the ratio of the mass of grit to the mass of quicklime (remaining particles on a 124-hole sieve /cm).2), in %. The smaller the amount of grit, the more the lime can react with the water, the more lime will be produced.
- Fineness of quicklime powder.
The finer the quicklime powder, the easier it is to react with the water completely, forming more lime mortar.
The basic criteria for assessing the quality of lime are specified according to TCVN 2231 – 1989
Target name | Lime lumps and crushed lime | ||
Type I | Type II | Type II | |
Lime curing speed (min) | |||
I’m fast (lower) | ten | ten | ten |
I’m average (lower) | 20 | 20 | 20 |
I’m slow (older) | 20 | 20 | 20 |
Magnesium oxide content (%) (lower) | 5 | 5 | 5 |
Total active (CaO+MgO) content (%), (more than) | 88 | 80 | 70 |
Fineness of slaked lime, l/kg, (greater than) | 2.4 | 2.0 | 1.6 |
Non-hardening particles of lime (%), (lower) | 5 | 7 | ten |
Fineness of lime powder (% ), (lower) |
|
|
|
On 0.063 . sieve | 2 | 2 | 2 |
On sieve 0.008 | ten | ten | ten |
Distinguish quicklime – slaked lime (powder lime) – limestone
1. Quicklime
Quicklime, also known as Calcium oxide, is a chemical compound with the formula CaO. They have distinguishing features: They are white crystalline powder or clumps.
2. Lime
Slaked lime, also known as Calcium hydroxide, is a chemical compound with the formula Ca(OH)2. They are colorless crystals or white powders, and are obtained when calcium oxide is reacted with water.
Slaked lime is used quite commonly in industry in different fields such as water treatment, cleaning, construction, fertilizer production, etc.
3. Limestone
Limestone is known as a sedimentary rock, with the main chemical composition of calcite and aragonite minerals.
Limestone is rarely pure and often mixed with impurities such as silicon shale, silica or igneous rock as well as clay, mud, sand, bitumen… Therefore, it has all colors from white to colored. ash, light blue, yellow and even dark pink or black…
Application of Calcium Oxide
Lime is commonly used in two forms: ripe lime and quicklime powder.
1. Ripe lime
Ripe lime is lime that is taken away (ie, quicklime is added to the water).
CaO + H2O → Ca(OH)2 + Q
The reaction gives off a lot of heat, the water boils, if not careful, it can cause severe burns. The smoke is white due to the presence of calcium hydroxide particles.
Lime powder
Depending on the amount of water carried away to slake the lime, people are divided into 3 types of ripe lime:
- Ripe lime powder: The amount of water used is equivalent to 70% of the mass of lime because the water is evaporated due to the heat generated from the reaction. The volumetric weight of lime powder ranges from 400-450 kg/m .3.
- Lime puree: The amount of water used is more than 70% of the mass of lime. Then the product formed is a slurry in which calcium hydroxide accounts for about 50%, the rest is water. The volumetric weight of lime puree ranges from 1200 to 1400 kg/m .3.
- Milk lime: The amount of water used is greater than the amount of water used for lime puree. Then the product formed is a slurry in which calcium hydroxide accounts for less than 50%, the rest is water.
2. Quicklime powder
To produce quicklime powder, lime lumps are ground to a fine powder. They are then stored in sealed bags and used like cement.
Advantages and disadvantages of ripe lime and quicklime powder
| Ripe lime | Quicklime powder |
Advantages | Easy to store and use | – Solid fast. – High bearing strength due to taking advantage of the heat released when liming to create a silicate reaction. – Limit the harmful effects of grit particles, don’t waste my time |
Defect | – Low bearing strength. – It is difficult to limit the harmful effects of old fire grains, so it is necessary to carefully screen these particles before use. | – Difficult to maintain because they are very hygroscopic, reducing the quality of lime. – For production, the number of equipment needed is quite a lot, and at the same time, the lime dust generated has an adverse effect on the health of workers. |
Quicklime powder application:
Proportion of lime use by industries
Application areas | Ratio |
Steel, metallurgy | thirty first |
Paper | 5 |
Light powder | 6 |
Environment treatment | 34 |
Build | ten |
Other industries (chemicals, food, etc.) | 14 |
- In the construction industry such as houses, schools, public works, etc., milk lime, pure lime or quicklime powder are commonly used.
People proceed to mix lime, sand, cement, and water in certain proportions, forming a mixture of mortar and plaster. Lime mortar has high cohesion because the loss of water when dry causes calcium hydroxide to crystallize at the same time, carbon dioxide in the air causes lime carbonation, making the mixture solid.
Lime is used to mix mortar in construction
- Producing silicate bricks, glass, sweeping ceilings, walls, as a solvent in the paper industry.
- Used in the metallurgical industry and as a raw material for the chemical industry, to remove slag impurities in the metal and alloy manufacturing industry thanks to its ability to react with silicate salts.
- In the wastewater treatment industry, quicklime acts as an additive to soften, flocculate, recover and remove inorganic and organic impurities containing phosphate, using quicklime to dissolve the amount of lignin in the industry. paper industry…
- Clear lime water is used to soak squash, carrots, … in jam processing, making them more crispy.
Processing jams with clear lime juice
- Lime used for aquaculture has the effect of removing alum, antiseptic, fungicidal, detoxicating the environment, reducing the pH to help de-acidification, improving the soil.
Lime powder for soil improvement
Clean the environment with lime powder
Used to purify citric acid, glucose, dyes.
In ceramic production:
Used as a melting aid for medium-fired, high-fired glazes at 1100oC, which helps the formed product to have higher hardness, less scratches, keep the enamel color and be resistant to acids.
Reduces viscosity for high silica glazes.
Enhance the hardness of ceramic glaze
- Calcium oxide has strong hygroscopic properties, so it is used to dry many substances.
Store lime properly
- In a hurry, it should not be left for a long time, to avoid the lime reacting with water vapor in the air to reduce quality. So I either mash it up as soon as possible or grind it up finely and store it in an airtight container.
- Pure lime should be soaked in pits with a layer of sand or water on top, with a thickness of 10-20 cm to prevent contact of lime with carbon dioxide in the air. The reaction takes place as follows:
Ca(OH)2 + CO2 → CaCO3 + FRIENDS2O
- If the lime is petrified with calcium carbonate, the quality of the lime will be reduced and its plasticity will be reduced, reducing its ability to stick.
TRƯỜNG THPT TRẦN HƯNG ĐẠO- Address to buy quality Calcium oxide in Hanoi
Established in 2000, experiencing nearly 20 years of construction and development, TRƯỜNG THPT TRẦN HƯNG ĐẠO rose to become the leading company in importing and distributing all kinds of chemicals, tools, scientific and technical equipment in Vietnam.
With the criterion of “Cooperation for mutual development” and the orientation of “Continuous improvement, constantly improving product quality”, TRƯỜNG THPT TRẦN HƯNG ĐẠO has always made great efforts in human resource training, improving facilities, building brand reputation, becoming a reliable partner for many large domestic and foreign companies and agents as well as customers in the market from North to South.
When buying Calcium oxide at TRƯỜNG THPT TRẦN HƯNG ĐẠO, you can be completely assured of product quality and price. Not only that, the company’s delivery staff will help the products reach the customers’ hands in a quick and accurate time as scheduled.
Hopefully, the above article of TRƯỜNG THPT TRẦN HƯNG ĐẠO will help readers understand Calcium oxide and its applications in life. If you are interested in our products, please contact us directly for the best advice and support. Sincerely thank!
See more:
- Calcium hydroxide- Properties, preparation procedures and common applications
- Methods for the preparation of acetic acid CH3COOH and applications of acetic acid
[toggle title=”xem thêm thông tin chi tiết về Những ứng dụng phổ biến của Canxi oxit CaO trong công nghiệp, xây dựng và đời sống sinh hoạt hàng ngày” state=”close”]
Những ứng dụng phổ quát của Canxi oxit CaO trong công nghiệp, xây dựng và đời sống sinh hoạt hàng ngày
Hình Ảnh về: Những ứng dụng phổ quát của Canxi oxit CaO trong công nghiệp, xây dựng và đời sống sinh hoạt hàng ngày
Video về: Những ứng dụng phổ quát của Canxi oxit CaO trong công nghiệp, xây dựng và đời sống sinh hoạt hàng ngày
Wiki về Những ứng dụng phổ quát của Canxi oxit CaO trong công nghiệp, xây dựng và đời sống sinh hoạt hàng ngày
Những ứng dụng phổ quát của Canxi oxit CaO trong công nghiệp, xây dựng và đời sống sinh hoạt hàng ngày -
Calcium oxide CaO also known by other names such as calcium, quicklime or calcined lime, is a white, caustic and alkaline crystalline solid that is solid at room temperature. It is a commercial product containing magnesium oxide, silicon oxide, smaller amounts of aluminum oxide and iron oxide, which is widely used in life, especially in the field of metallurgy and environmental treatment. In India before, when soap was not discovered, it was mixed with sand and used to clean the body. So calcium oxide How is it manufactured, and what specific applications are there? . This article will answer those questions for you
Overview of Calcium oxide
What is calcium oxide CaO? Quicklime. Physical and chemical properties
Calcium oxide CaO is also known by other names such as calcium, quicklime or calcined lime.
Molecular Formula | High |
Physical state | crystalline solid |
Color | White |
Nature | It is caustic, alkaline |
Element | In addition to CaO, quicklime also contains impurities such as Magnesium oxide, Silicon oxide, Aluminum oxide, Iron II oxide |
Molar mass | 56.1 g/mol |
Expansion coefficient | 0.148 |
Melting point | 2850oC (3123 K) |
Melting temperature | 2572oC (2845 K) |
Specific gravity | 3.3- 3.4 x 103 kg/m3 |
The solubility | Soluble in water |
Crystal structure | Cubic face center |
Melting temperature | 2572oC (2845 K) |
Calcium oxide is a basic oxide so it has all the properties of a basic oxide.
- Effect with water
CaO + H2O → Ca(OH)2
- React with acids to form salt and water
CaO + 2HCl → CaCl2 + FRIENDS2O
- React with acidic oxides to form salts
CaO + CO2 → CaCO3
The reaction that occurs when quicklime is added to water
CaO + H2O → Ca(OH)2
Calcium oxide production process - Quicklime
Raw materials used to produce quicklime are rocks rich in calcium carbonate minerals, mainly limestone. There are also some other types such as coral stone, dolomite rock (clay content less than 6%).
Quicklime production line
Crush the stone into small balls of uniform size 10-20cm before heating in the oven at a high temperature of 900-1100.oC. The fuel used is firewood, oil, natural gas, etc. The reaction occurs as follows:
Burning coal produces CO2 and give off a lot of heat
C + O2 → CO2
The heat generated decomposes limestone
CaCO3 ↔CAO + CO2 - Q (heat)
This is a reversible reaction. Therefore, if you want to increase the quality of lime, it is necessary to push the forward direction by creating ventilation in the lime kiln so that CO2 exit easily.
Handmade lime kiln
Note:
If the stones to be fired are of irregular size, quicklime and burnt lime are very likely to occur.
- If large stones are heated, calcium carbonate will not completely convert to calcium oxide, causing the finished product to have poor quality, many stones, and less plasticity.
- With small sized stones or too high temperature in the kiln, the generated calcium oxide will react with clay impurities to form a very hard calcium silicate, calcium aluminate colloidal film. They cover the lime particles making it difficult for them to hydrolyze in water, lime absorbs water and absorbs much moisture, increasing the volume, causing the structure to be pitted and cracked.
Criteria for assessing quality of Quicklime
Lime quality depends on calcium oxide content.
Quicklime
The criteria for assessing lime quality:
- The activity of lime: Depends on the content of calcium oxide, magnesium oxide. The larger the amount, the more lime and mortar output and vice versa.
- I temperature (the highest temperature of the curing process) and the curing time (from the time the lime is added to the water to the maximum boiling point): The greater the amount of heat released when slaked, the longer the curing time. The shorter the time, the purer the lime, the higher the calcium oxide content. The output of lime mortar will be much.
- Lime yield: The higher the quantity of lime, the better the quality of lime. They depend on calcium oxide content, temperature, curing time.
- The amount of grit (unhardened lime in lime mortar): The amount of grit is the ratio of the mass of grit to the mass of quicklime (remaining particles on a 124-hole sieve /cm).2), in %. The smaller the amount of grit, the more the lime can react with the water, the more lime will be produced.
- Fineness of quicklime powder.
The finer the quicklime powder, the easier it is to react with the water completely, forming more lime mortar.
The basic criteria for assessing the quality of lime are specified according to TCVN 2231 - 1989
Target name | Lime lumps and crushed lime | ||
Type I | Type II | Type II | |
Lime curing speed (min) | |||
I'm fast (lower) | ten | ten | ten |
I'm average (lower) | 20 | 20 | 20 |
I'm slow (older) | 20 | 20 | 20 |
Magnesium oxide content (%) (lower) | 5 | 5 | 5 |
Total active (CaO+MgO) content (%), (more than) | 88 | 80 | 70 |
Fineness of slaked lime, l/kg, (greater than) | 2.4 | 2.0 | 1.6 |
Non-hardening particles of lime (%), (lower) | 5 | 7 | ten |
Fineness of lime powder (% ), (lower) |
|
|
|
On 0.063 . sieve | 2 | 2 | 2 |
On sieve 0.008 | ten | ten | ten |
Distinguish quicklime - slaked lime (powder lime) - limestone
1. Quicklime
Quicklime, also known as Calcium oxide, is a chemical compound with the formula CaO. They have distinguishing features: They are white crystalline powder or clumps.
2. Lime
Slaked lime, also known as Calcium hydroxide, is a chemical compound with the formula Ca(OH)2. They are colorless crystals or white powders, and are obtained when calcium oxide is reacted with water.
Slaked lime is used quite commonly in industry in different fields such as water treatment, cleaning, construction, fertilizer production, etc.
3. Limestone
Limestone is known as a sedimentary rock, with the main chemical composition of calcite and aragonite minerals.
Limestone is rarely pure and often mixed with impurities such as silicon shale, silica or igneous rock as well as clay, mud, sand, bitumen... Therefore, it has all colors from white to colored. ash, light blue, yellow and even dark pink or black...
Application of Calcium Oxide
Lime is commonly used in two forms: ripe lime and quicklime powder.
1. Ripe lime
Ripe lime is lime that is taken away (ie, quicklime is added to the water).
CaO + H2O → Ca(OH)2 + Q
The reaction gives off a lot of heat, the water boils, if not careful, it can cause severe burns. The smoke is white due to the presence of calcium hydroxide particles.
Lime powder
Depending on the amount of water carried away to slake the lime, people are divided into 3 types of ripe lime:
- Ripe lime powder: The amount of water used is equivalent to 70% of the mass of lime because the water is evaporated due to the heat generated from the reaction. The volumetric weight of lime powder ranges from 400-450 kg/m .3.
- Lime puree: The amount of water used is more than 70% of the mass of lime. Then the product formed is a slurry in which calcium hydroxide accounts for about 50%, the rest is water. The volumetric weight of lime puree ranges from 1200 to 1400 kg/m .3.
- Milk lime: The amount of water used is greater than the amount of water used for lime puree. Then the product formed is a slurry in which calcium hydroxide accounts for less than 50%, the rest is water.
2. Quicklime powder
To produce quicklime powder, lime lumps are ground to a fine powder. They are then stored in sealed bags and used like cement.
Advantages and disadvantages of ripe lime and quicklime powder
| Ripe lime | Quicklime powder |
Advantages | Easy to store and use | - Solid fast. - High bearing strength due to taking advantage of the heat released when liming to create a silicate reaction. - Limit the harmful effects of grit particles, don't waste my time |
Defect | - Low bearing strength. - It is difficult to limit the harmful effects of old fire grains, so it is necessary to carefully screen these particles before use. | - Difficult to maintain because they are very hygroscopic, reducing the quality of lime. - For production, the number of equipment needed is quite a lot, and at the same time, the lime dust generated has an adverse effect on the health of workers. |
Quicklime powder application:
Proportion of lime use by industries
Application areas | Ratio |
Steel, metallurgy | thirty first |
Paper | 5 |
Light powder | 6 |
Environment treatment | 34 |
Build | ten |
Other industries (chemicals, food, etc.) | 14 |
- In the construction industry such as houses, schools, public works, etc., milk lime, pure lime or quicklime powder are commonly used.
People proceed to mix lime, sand, cement, and water in certain proportions, forming a mixture of mortar and plaster. Lime mortar has high cohesion because the loss of water when dry causes calcium hydroxide to crystallize at the same time, carbon dioxide in the air causes lime carbonation, making the mixture solid.
Lime is used to mix mortar in construction
- Producing silicate bricks, glass, sweeping ceilings, walls, as a solvent in the paper industry.
- Used in the metallurgical industry and as a raw material for the chemical industry, to remove slag impurities in the metal and alloy manufacturing industry thanks to its ability to react with silicate salts.
- In the wastewater treatment industry, quicklime acts as an additive to soften, flocculate, recover and remove inorganic and organic impurities containing phosphate, using quicklime to dissolve the amount of lignin in the industry. paper industry...
- Clear lime water is used to soak squash, carrots, ... in jam processing, making them more crispy.
Processing jams with clear lime juice
- Lime used for aquaculture has the effect of removing alum, antiseptic, fungicidal, detoxicating the environment, reducing the pH to help de-acidification, improving the soil.
Lime powder for soil improvement
Clean the environment with lime powder
Used to purify citric acid, glucose, dyes.
In ceramic production:
Used as a melting aid for medium-fired, high-fired glazes at 1100oC, which helps the formed product to have higher hardness, less scratches, keep the enamel color and be resistant to acids.
Reduces viscosity for high silica glazes.
Enhance the hardness of ceramic glaze
- Calcium oxide has strong hygroscopic properties, so it is used to dry many substances.
Store lime properly
- In a hurry, it should not be left for a long time, to avoid the lime reacting with water vapor in the air to reduce quality. So I either mash it up as soon as possible or grind it up finely and store it in an airtight container.
- Pure lime should be soaked in pits with a layer of sand or water on top, with a thickness of 10-20 cm to prevent contact of lime with carbon dioxide in the air. The reaction takes place as follows:
Ca(OH)2 + CO2 → CaCO3 + FRIENDS2O
- If the lime is petrified with calcium carbonate, the quality of the lime will be reduced and its plasticity will be reduced, reducing its ability to stick.
TRƯỜNG THPT TRẦN HƯNG ĐẠO- Address to buy quality Calcium oxide in Hanoi
Established in 2000, experiencing nearly 20 years of construction and development, TRƯỜNG THPT TRẦN HƯNG ĐẠO rose to become the leading company in importing and distributing all kinds of chemicals, tools, scientific and technical equipment in Vietnam.
With the criterion of "Cooperation for mutual development" and the orientation of "Continuous improvement, constantly improving product quality", TRƯỜNG THPT TRẦN HƯNG ĐẠO has always made great efforts in human resource training, improving facilities, building brand reputation, becoming a reliable partner for many large domestic and foreign companies and agents as well as customers in the market from North to South.
When buying Calcium oxide at TRƯỜNG THPT TRẦN HƯNG ĐẠO, you can be completely assured of product quality and price. Not only that, the company's delivery staff will help the products reach the customers' hands in a quick and accurate time as scheduled.
Hopefully, the above article of TRƯỜNG THPT TRẦN HƯNG ĐẠO will help readers understand Calcium oxide and its applications in life. If you are interested in our products, please contact us directly for the best advice and support. Sincerely thank!
See more:
- Calcium hydroxide- Properties, preparation procedures and common applications
- Methods for the preparation of acetic acid CH3COOH and applications of acetic acid
[rule_{ruleNumber}]
[box type=”note” align=”” class=”” text-align: justify;”>Calcium oxide CaO also known by other names such as calcium, quicklime or calcined lime, is a white, caustic and alkaline crystalline solid that is solid at room temperature. It is a commercial product containing magnesium oxide, silicon oxide, smaller amounts of aluminum oxide and iron oxide, which is widely used in life, especially in the field of metallurgy and environmental treatment. In India before, when soap was not discovered, it was mixed with sand and used to clean the body. So calcium oxide How is it manufactured, and what specific applications are there? . This article will answer those questions for you
Overview of Calcium oxide
What is calcium oxide CaO? Quicklime. Physical and chemical properties
Calcium oxide CaO is also known by other names such as calcium, quicklime or calcined lime.
Molecular Formula | High |
Physical state | crystalline solid |
Color | White |
Nature | It is caustic, alkaline |
Element | In addition to CaO, quicklime also contains impurities such as Magnesium oxide, Silicon oxide, Aluminum oxide, Iron II oxide |
Molar mass | 56.1 g/mol |
Expansion coefficient | 0.148 |
Melting point | 2850oC (3123 K) |
Melting temperature | 2572oC (2845 K) |
Specific gravity | 3.3- 3.4 x 103 kg/m3 |
The solubility | Soluble in water |
Crystal structure | Cubic face center |
Melting temperature | 2572oC (2845 K) |
Calcium oxide is a basic oxide so it has all the properties of a basic oxide.
- Effect with water
CaO + H2O → Ca(OH)2
- React with acids to form salt and water
CaO + 2HCl → CaCl2 + FRIENDS2O
- React with acidic oxides to form salts
CaO + CO2 → CaCO3
The reaction that occurs when quicklime is added to water
CaO + H2O → Ca(OH)2
Calcium oxide production process – Quicklime
Raw materials used to produce quicklime are rocks rich in calcium carbonate minerals, mainly limestone. There are also some other types such as coral stone, dolomite rock (clay content less than 6%).
Quicklime production line
Crush the stone into small balls of uniform size 10-20cm before heating in the oven at a high temperature of 900-1100.oC. The fuel used is firewood, oil, natural gas, etc. The reaction occurs as follows:
Burning coal produces CO2 and give off a lot of heat
C + O2 → CO2
The heat generated decomposes limestone
CaCO3 ↔CAO + CO2 – Q (heat)
This is a reversible reaction. Therefore, if you want to increase the quality of lime, it is necessary to push the forward direction by creating ventilation in the lime kiln so that CO2 exit easily.
Handmade lime kiln
Note:
If the stones to be fired are of irregular size, quicklime and burnt lime are very likely to occur.
- If large stones are heated, calcium carbonate will not completely convert to calcium oxide, causing the finished product to have poor quality, many stones, and less plasticity.
- With small sized stones or too high temperature in the kiln, the generated calcium oxide will react with clay impurities to form a very hard calcium silicate, calcium aluminate colloidal film. They cover the lime particles making it difficult for them to hydrolyze in water, lime absorbs water and absorbs much moisture, increasing the volume, causing the structure to be pitted and cracked.
Criteria for assessing quality of Quicklime
Lime quality depends on calcium oxide content.
Quicklime
The criteria for assessing lime quality:
- The activity of lime: Depends on the content of calcium oxide, magnesium oxide. The larger the amount, the more lime and mortar output and vice versa.
- I temperature (the highest temperature of the curing process) and the curing time (from the time the lime is added to the water to the maximum boiling point): The greater the amount of heat released when slaked, the longer the curing time. The shorter the time, the purer the lime, the higher the calcium oxide content. The output of lime mortar will be much.
- Lime yield: The higher the quantity of lime, the better the quality of lime. They depend on calcium oxide content, temperature, curing time.
- The amount of grit (unhardened lime in lime mortar): The amount of grit is the ratio of the mass of grit to the mass of quicklime (remaining particles on a 124-hole sieve /cm).2), in %. The smaller the amount of grit, the more the lime can react with the water, the more lime will be produced.
- Fineness of quicklime powder.
The finer the quicklime powder, the easier it is to react with the water completely, forming more lime mortar.
The basic criteria for assessing the quality of lime are specified according to TCVN 2231 – 1989
Target name | Lime lumps and crushed lime | ||
Type I | Type II | Type II | |
Lime curing speed (min) | |||
I’m fast (lower) | ten | ten | ten |
I’m average (lower) | 20 | 20 | 20 |
I’m slow (older) | 20 | 20 | 20 |
Magnesium oxide content (%) (lower) | 5 | 5 | 5 |
Total active (CaO+MgO) content (%), (more than) | 88 | 80 | 70 |
Fineness of slaked lime, l/kg, (greater than) | 2.4 | 2.0 | 1.6 |
Non-hardening particles of lime (%), (lower) | 5 | 7 | ten |
Fineness of lime powder (% ), (lower) |
|
|
|
On 0.063 . sieve | 2 | 2 | 2 |
On sieve 0.008 | ten | ten | ten |
Distinguish quicklime – slaked lime (powder lime) – limestone
1. Quicklime
Quicklime, also known as Calcium oxide, is a chemical compound with the formula CaO. They have distinguishing features: They are white crystalline powder or clumps.
2. Lime
Slaked lime, also known as Calcium hydroxide, is a chemical compound with the formula Ca(OH)2. They are colorless crystals or white powders, and are obtained when calcium oxide is reacted with water.
Slaked lime is used quite commonly in industry in different fields such as water treatment, cleaning, construction, fertilizer production, etc.
3. Limestone
Limestone is known as a sedimentary rock, with the main chemical composition of calcite and aragonite minerals.
Limestone is rarely pure and often mixed with impurities such as silicon shale, silica or igneous rock as well as clay, mud, sand, bitumen… Therefore, it has all colors from white to colored. ash, light blue, yellow and even dark pink or black…
Application of Calcium Oxide
Lime is commonly used in two forms: ripe lime and quicklime powder.
1. Ripe lime
Ripe lime is lime that is taken away (ie, quicklime is added to the water).
CaO + H2O → Ca(OH)2 + Q
The reaction gives off a lot of heat, the water boils, if not careful, it can cause severe burns. The smoke is white due to the presence of calcium hydroxide particles.
Lime powder
Depending on the amount of water carried away to slake the lime, people are divided into 3 types of ripe lime:
- Ripe lime powder: The amount of water used is equivalent to 70% of the mass of lime because the water is evaporated due to the heat generated from the reaction. The volumetric weight of lime powder ranges from 400-450 kg/m .3.
- Lime puree: The amount of water used is more than 70% of the mass of lime. Then the product formed is a slurry in which calcium hydroxide accounts for about 50%, the rest is water. The volumetric weight of lime puree ranges from 1200 to 1400 kg/m .3.
- Milk lime: The amount of water used is greater than the amount of water used for lime puree. Then the product formed is a slurry in which calcium hydroxide accounts for less than 50%, the rest is water.
2. Quicklime powder
To produce quicklime powder, lime lumps are ground to a fine powder. They are then stored in sealed bags and used like cement.
Advantages and disadvantages of ripe lime and quicklime powder
| Ripe lime | Quicklime powder |
Advantages | Easy to store and use | – Solid fast. – High bearing strength due to taking advantage of the heat released when liming to create a silicate reaction. – Limit the harmful effects of grit particles, don’t waste my time |
Defect | – Low bearing strength. – It is difficult to limit the harmful effects of old fire grains, so it is necessary to carefully screen these particles before use. | – Difficult to maintain because they are very hygroscopic, reducing the quality of lime. – For production, the number of equipment needed is quite a lot, and at the same time, the lime dust generated has an adverse effect on the health of workers. |
Quicklime powder application:
Proportion of lime use by industries
Application areas | Ratio |
Steel, metallurgy | thirty first |
Paper | 5 |
Light powder | 6 |
Environment treatment | 34 |
Build | ten |
Other industries (chemicals, food, etc.) | 14 |
- In the construction industry such as houses, schools, public works, etc., milk lime, pure lime or quicklime powder are commonly used.
People proceed to mix lime, sand, cement, and water in certain proportions, forming a mixture of mortar and plaster. Lime mortar has high cohesion because the loss of water when dry causes calcium hydroxide to crystallize at the same time, carbon dioxide in the air causes lime carbonation, making the mixture solid.
Lime is used to mix mortar in construction
- Producing silicate bricks, glass, sweeping ceilings, walls, as a solvent in the paper industry.
- Used in the metallurgical industry and as a raw material for the chemical industry, to remove slag impurities in the metal and alloy manufacturing industry thanks to its ability to react with silicate salts.
- In the wastewater treatment industry, quicklime acts as an additive to soften, flocculate, recover and remove inorganic and organic impurities containing phosphate, using quicklime to dissolve the amount of lignin in the industry. paper industry…
- Clear lime water is used to soak squash, carrots, … in jam processing, making them more crispy.
Processing jams with clear lime juice
- Lime used for aquaculture has the effect of removing alum, antiseptic, fungicidal, detoxicating the environment, reducing the pH to help de-acidification, improving the soil.
Lime powder for soil improvement
Clean the environment with lime powder
Used to purify citric acid, glucose, dyes.
In ceramic production:
Used as a melting aid for medium-fired, high-fired glazes at 1100oC, which helps the formed product to have higher hardness, less scratches, keep the enamel color and be resistant to acids.
Reduces viscosity for high silica glazes.
Enhance the hardness of ceramic glaze
- Calcium oxide has strong hygroscopic properties, so it is used to dry many substances.
Store lime properly
- In a hurry, it should not be left for a long time, to avoid the lime reacting with water vapor in the air to reduce quality. So I either mash it up as soon as possible or grind it up finely and store it in an airtight container.
- Pure lime should be soaked in pits with a layer of sand or water on top, with a thickness of 10-20 cm to prevent contact of lime with carbon dioxide in the air. The reaction takes place as follows:
Ca(OH)2 + CO2 → CaCO3 + FRIENDS2O
- If the lime is petrified with calcium carbonate, the quality of the lime will be reduced and its plasticity will be reduced, reducing its ability to stick.
TRƯỜNG THPT TRẦN HƯNG ĐẠO- Address to buy quality Calcium oxide in Hanoi
Established in 2000, experiencing nearly 20 years of construction and development, TRƯỜNG THPT TRẦN HƯNG ĐẠO rose to become the leading company in importing and distributing all kinds of chemicals, tools, scientific and technical equipment in Vietnam.
With the criterion of “Cooperation for mutual development” and the orientation of “Continuous improvement, constantly improving product quality”, TRƯỜNG THPT TRẦN HƯNG ĐẠO has always made great efforts in human resource training, improving facilities, building brand reputation, becoming a reliable partner for many large domestic and foreign companies and agents as well as customers in the market from North to South.
When buying Calcium oxide at TRƯỜNG THPT TRẦN HƯNG ĐẠO, you can be completely assured of product quality and price. Not only that, the company’s delivery staff will help the products reach the customers’ hands in a quick and accurate time as scheduled.
Hopefully, the above article of TRƯỜNG THPT TRẦN HƯNG ĐẠO will help readers understand Calcium oxide and its applications in life. If you are interested in our products, please contact us directly for the best advice and support. Sincerely thank!
See more:
- Calcium hydroxide- Properties, preparation procedures and common applications
- Methods for the preparation of acetic acid CH3COOH and applications of acetic acid
[/box]
#Những #ứng #dụng #phổ #biến #của #Canxi #oxit #CaO #trong #công #nghiệp #xây #dựng #và #đời #sống #sinh #hoạt #hàng #ngày
[/toggle]
Bạn thấy bài viết Những ứng dụng phổ quát của Canxi oxit CaO trong công nghiệp, xây dựng và đời sống sinh hoạt hàng ngày có khắc phục đươc vấn đề bạn tìm hiểu ko?, nếu ko hãy comment góp ý thêm về Những ứng dụng phổ quát của Canxi oxit CaO trong công nghiệp, xây dựng và đời sống sinh hoạt hàng ngày bên dưới để thpttranhungdao.edu.vn có thể thay đổi & cải thiện nội dung tốt hơn cho độc giả nhé! Cám ơn bạn đã ghé thăm Website Trường THPT Trần Hưng Đạo
Phân mục: Kiến thức chung
#Những #ứng #dụng #phổ #biến #của #Canxi #oxit #CaO #trong #công #nghiệp #xây #dựng #và #đời #sống #sinh #hoạt #hàng #ngày
Trả lời