lime lime

タイトルまたは説明

 Limestone
Hydrated lime –quick lime – natural lime

General limestone
Category Carbonate mineral

Chemical formula
CaCO3
 
Crystal symmetry
Trigonal
 
Identification
Color Colorless or white, also gray, yellow, green,
Crystal habit
Crystalline, granular, massive, rhombohedral.
Crystal system
Trigonal hexagonal

Twinning
Common by four twin laws
Cleavage
Perfect on [***1]
Fracture
Conchoidal
Tenacity Brittle
Mohs scale hardness 3
Luster
Vitreous to pearly on cleavage surfaces
Streak
White
Diaphaneity
Transparent to translucent
Specific gavity
2.*1
 
 
 
Solubility
Soluble in dilute acids
Other characteristics May fluoresce red, blue, yellow, and other colors under either SW and LW UV; phosphorescent

Properties hydrated lime
Molecular formula
Ca(OH)2
Molar mass
*4.**3 g/mol
Exact mass
*3.*****1
Appearance soft white powder/colourless liquid
Odor
odorless
Density
2.**1 g/cm3, solid
Melting point
**0 °C (loses water)
Solubility in water
0.**9 g/**0 mL (0 °C)
0.**3 g/**0 mL (*0 °C)
0.**6 g/**0 mL (**0 °C)
Solubility product, Ksp 4.*8×*0−6
Solubility
Soluble in glycerol and acids.
Insoluble in alcohol.

Acidity (pKa)
*2.4
Basicity (pKb)
2.*7
 
Thermochemistry
Std enthalpy of
formation ΔfHo**8
−**7 kJ•mol−1[1]

Standard molar
entropy So**8
*3 J•mol−1•K−1[

Properties quick lime
Molecular formula
CaO
Molar mass
*6.***4 g/mol
Exact mass
*5.*****6
Appearance White to pale yellow/brown powder
Odor
odorless
Density
3.*5 g/cm3
Melting point
***2 °C, ***5 K, ***2 °F
Boiling point
***0 °C, ***3 K, ***2 °F
Solubility in water
reacts
Solubility in [[acids, glycerol, sugar solution]]
soluble
Solubility in [[methanol, diethyl ether, n-octanol]]
insoluble
Acidity (pKa)
*2.8
Thermochemistry
Std enthalpy of
formation ΔfHo**8
−**5 kJ•mol−1
Standard molar
entropy So**8
*0 J•mol−1•K−1

Analysis limestone

•  Cao% sio2 % Mgo% R2O3 CI % S% P % LIO %
*4.*6 *0.*6 *0.*1 *0.*6 0.*6 *0.*3 *0.*2 *3.*0

Tested Item Specifications
% Of CaCo3 in stone Min *9 %
Fe2O3 Max 0.*1%
SiO2 Max 0.*6%
MgO Max 0.*8
HCL insoluble content Max 0.*8 %
Brightness *6%
L.O.I *3.5
Particle Size Varies from **0 Micron up to 2 Micron
Colour Pure White

Chemical analysis Raw material: Hydrated Lime
Tested Item Specifications
Ca(OH)2 Min *0 %
MgO Max 0.1 %
SO3 Max 0.*0 %
CI Max 0.*2 %
Fe2O3 Max 0.*8%
Al2O3 Max 0.*1%
Defects Max 2.5%
Particle Size *5 Micron
Color White
Chemical analysis  Quick Lime

% Of Cao Min *0 %
Extinguishments time More than *0o C in 5 minutes
% Of Calcium carbonate Max 3 %
Defects *0 - *5 %
Particle Size
* Lumps 3 – 8 cm
* Varies from **0 Micron up to *0 Micron
Color Pure White or dark white

General limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera.
Limestone makes up about *0% of the total volume of all sedimentary rocks. The solubility of limestone in water and weak acid solutions leads to karst landscapes, in which water erodes the limestone over thousands to millions of years

Rock contain more than *0% of calcite , about *0 % of  earth crust .
Aragonite is a metastable polymorph of calcite Formed by precipitation in tropic or semi tropic region , The most common
mineral impurities are quartz and clay. The most common substitutes for calcium are other divalent cations , such as magnesium, strontium, and barium .
the exception is magnesium, which can substantially replace calcium to form the mineral dolomite, CaMg(CO3)2
.

General hydrated lime

Calcium hydroxide, traditionally called slaked lime, is an inorganic compound with the chemical formula Ca(OH)2. It is a colorless crystal or white powder and is obtained when calcium oxide (called lime or quicklime) is mixed, or "slaked" with water. It has many names including hydrated lime, builders lime, slack lime, cal, or pickling lime. It is of low toxicity. Calcium hydroxide is used in many applications, including food preparation
When heated to **2 °C, the partial pressure of water in equilibrium with calcium hydroxide reaches **1 kPa, which decomposes calcium hydroxide into calcium oxide and water.[3]
Ca(OH)2 → CaO + H2O
A suspension of fine calcium hydroxide particles in water is called milk of lime. The solution is called lime water and is a medium strength base that reacts with acids and attacks many metals. Lime water turns milky in the presence of carbon dioxide due to formation of calcium carbonate:
Ca(OH)2 + CO2 → CaCO3 + H2O
Calcium hydroxide crystallizes in the same motif as cadmium iodide. The layers are interconnected by hydrogen bonds.
General quick lime

Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline crystalline solid at room temperature. The broadly used term lime connotes calcium-containing inorganic materials, in which carbonates, oxides and hydroxides of calcium, silicon, magnesium, aluminium, and iron predominate, such as limestone.
Calcium oxide is usually made by the thermal decomposition of materials such as limestone, that contain calcium carbonate (CaCO3; mineral calcite) in a lime kiln. This is accomplished by heating the material to above **5 °C (1,**7 °F), a process called calcination or lime-burning, to liberate a molecule of carbon dioxide (CO2); leaving quicklime. The quicklime is not stable and, when cooled, will spontaneously react with CO2 from the air until, after enough time, it is completely converted back to calcium carbonate

Uses limestone :
*- Portland cement industry : about *6 % that mix with nonmetallic minerals which is chemically treated .
*- Anhydrous sod carbonates : which is important to glass industry , detergence industry  , purification industry , by  reaction of co2 produce from calcinations with sod chloride and ammonia .
*- Catalyst in iron kilns : that iron have silica and ammonia as impurities which removed by limestone , they found that **0 kg of limestone produce 1 ton of iron .
*- Rocky fiber : by melting limestone in kilns and pumping steam strongly , so fiber formed which use as thermal isolation .
*- Lime industry : limestone is fired to lose co2 with *4 % from its weight leaving cao , that happen at ***0 – ***0 degree , which use in glass , paper building industry .
*- Metal filler : easy to grind , low oil absorption , do not cause machine corrosion isolation of tank and roofs , , painting and ceramic industries .
*- Food industry : the pure one for birds ,treatment for sugar .
*- Ornamental stone : and building .
*- paper : In alkaline papermaking , calcium carbonate is used as a paper filler and coating. Both uses require high brightness , high purity, small particle size , and lack of abrasion.
**- coating : used white pigment in paints because it is available at relatively low cost and has high brightness for TiO2 extension, high purity, low abrasivity, and resistance to weathering.
**- plastic and rubber industry : used filler in plastics due to its low cost, low abrasion, low oil absorption, low moisture, high brightness, and easy dispersion with conventional mixing equipment , In plastics they are used to improve mar and impact resistance, surface gloss, weatherability,shrinkage control, cold flow properties, low and high temperature properties, and dielectric properties, and to reduce plasticizer migration and crazing of molded parts.
**- Used in glaze ,ceramic tiles ,porcelain and potteries
Other uses include:
• It is the raw material for the manufacture of quicklime (calcium oxide), slaked lime (calcium hydroxide), cement and mortar.
• Pulverized limestone is used as a soil conditioner to neutralize acidic soils.
• It is crushed for use as aggregate—the solid base for many roads.
• Geological formations of limestone are among the best petroleum reservoirs;
• As a reagent in flue-gas desulfurization, it reacts with sulfur dioxide for air pollution control.
• Glass making, in some circumstances, uses limestone.
• It is added to toothpaste, paper and other materials as both white pigment and a cheap filler.
• It can suppress methane explosions in underground coal mines.
• Purified, it is added to bread and cereals as a source of calcium.
• Calcium levels in livestock feed are supplemented with it, such as for poultry (when ground up).
• It can be used for remineralizing and increasing the alkalinity of purified water to prevent pipe corrosion and to restore essential nutrient levelsUsed in blast furnaces, limestone extracts iron from its ore.
• It is often found in medicines and cosmetics.
• It is used in sculptures because of its suitability for carving.

Uses hydrated lime
One significant application of calcium hydroxide is as a flocculent, in water and sewage treatment. It forms a fluffy charged solid that aids in the removal of smaller particles from water, resulting in a clearer product. This application is enabled by the low cost and non-toxicity of calcium hydroxide. It is also used in fresh water treatment for raising the pH of the water so that the pipes will not corrode where the base water is acidic because it is self-regulating and does not raise the pH too much.
Another large application is in the paper industry, where it is used in the production of sodium hydroxide. This conversion is a component of the Kraft process
Because it is produced on a large scale, is easily handled, and is cheap, myriad niche and even large scale applications have been described. A partial listing follows:
• In life support systems as a carbon dioxide scrubber, particularly in closed-circuit diving re-breathers such as the US Navy LAR V or MK**6, where the more caustic Lithium Hydroxide is deemed too risky due to inhaled dust, combat handling, or generation of caustic "slurry" in flooding events
• An ingredient in whitewash, mortar, and plaster
• To fill the root canal for the first stage of endodontic therapy (it is then replaced by rubber).
• As an additive to sea water to reduce atmospheric CO2 and mitigate the greenhouse effect.[5]
• In the production of metals, lime is injected into the waste gas stream to neutralize acids, such as fluorides and chlorides prior to being released to atmosphere.
• An alkali used as a lye substitute in no-lye hair relaxers
• A chemical depilatory agent found in most hair removal creams (for example Nair)
• In Bordeaux mixture to neutralize the solution and form a long lasting fungicide
• In lime-sulfur it is mixed with sulfur and boiled in water for an hour. The ratio by weight of Ca(OH)2:S:water is about 1:1.7:8.7. Diluted (1:*2) lime-sulfur is sprayed as a fungicide and used as a dip to combat sarcoptic mange.
• In the petroleum refining industry for the manufacture of additives to oils (salicatic, sulphatic, fenatic)
• In the chemical industry for manufacture of calcium stearate
o In the petrochemical industry for manufacturing solid oil of various marks
o In the manufacture of brake pads
o In manufacturing the trademarked compound "Polikar", an antifungal and antimicrobial preservative for vegetables in storage
o For preparation of dry mixes for painting and decorating
o In manufacturing mixes for pesticides
o In the manufacture of ebonite
o As a calcium supplement and pH/carbonate buffer  for the aquaculture of corals in reef aquaria.
o As a natural "alternative" insecticide. Most crawling insects are killed by its touch. Including: ticks, fleas, beetles and grubs.
For making a fungicide or a dip for treating mange it is boiled with sulfur, then diluted. One recipe for the concentrate is *6 lb quicklime, *0 lb sulfur, and *0 gal water boiled for 1 hour—the authors suggesting 1/3 more lime if slaked lime is used.
 Food industry
Because of its low toxicity and the mildness of its basic properties, it is widely used in the food industry and associated hobbies: Examples:
• The separation of sugar from sugar cane or sugar beets in the sugar industry, see carbonatation
• For processing water for alcoholic beverages, soft drinks.
• Home food preservation in the making of pickles.
• Clearing a brine of carbonates of calcium and magnesium in the manufacture of salt for food and pharmacopoeia
• Used to fortify fruit drinks such as Tropicana Calcium + Vitamin D orange juice.
• A calcium supplement in mineral fortified infant formula
• Use as alternative ingredient to baking soda (raising agent

Uses quick lime
Quicklime is relatively inexpensive. Both it and a chemical derivative (calcium hydroxide) are important commodity chemicals.
Quicklime produces heat energy by the formation of the hydrate, calcium hydroxide, by the following equation:[3]
CaO (s) + H2O (l)  Ca(OH)2 (aq) (ΔHr = −*3.7 kJ/mol of CaO)
As it hydrates, an exothermic reaction results and the solid puffs up. The hydrate can be reconverted to quicklime by removing the water by heating it to redness to reverse the hydration reaction. One litre of water combines with approximately 3.1 kilograms (6.8 lb) of quicklime to give calcium hydroxide plus 3.*4 MJ of energy. This process can be used to provide a convenient portable source of heat, as for on-the-spot food warming in a self-heating can.
When quicklime is heated to 2,**0 °C (4,**0 °F), it emits an intense glow. This form of illumination is known as a limelight, and was used broadly in theatrical productions prior to the invention of electric lighting.
 Precipitated calcium carbonate is made by mixing calcium oxide into water, and then bubbling carbon dioxide into the solution. It is used by itself or with additives as a white paint, known as whitewashing.
Calcium oxide is also a key ingredient for the process of making cement.