Lime Stone
Description:
- Color varies depending on impurities, ranging from white or gray to tan, yellow, or even black.
- Can be a massive rock formation or exist in layered beds.
- Often has a fossiliferous texture due to the remains of marine organisms.
- May be compact and hard or more crumbly and soft depending on the formation process.
Uses:
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Construction:
- Crushed limestone is a major component of concrete and asphalt due to its strength and setting properties.
- Used as a building stone in some architectural applications (cut and polished limestone).
- Can be burned to produce quicklime (calcium oxide) for further processing into lime mortar and plaster.
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Manufacturing:
- A raw material for the production of Portland cement, a key building material.
- Used in the production of lime, a chemical with various industrial applications.
- Filler material in some plastics, rubber, and paints.
- Flux (material that lowers the melting point) in metal smelting.
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Environmental Applications:
- Crushed limestone can be used for soil pH modification (agricultural lime) to neutralize acidic soil.
- Used in flue gas desulfurization to remove sulfur dioxide emissions from power plants.
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Other Uses:
- Crushed limestone is used as a decorative landscape material (gravel).
- Can be crushed and sized for use in playground surfaces or athletic fields.
- Used in some pharmaceutical and food processing applications (as a calcium source with limitations due to potential impurities).
Chemical Composition:
- Primarily calcium carbonate (CaCO3) – makes up over 90% in most limestones.
- May contain small amounts of other minerals depending on the formation process, such as:
- Magnesium carbonate (MgCO3) – dolomitic limestone has a higher magnesium content.
- Clay minerals
- Silica (SiO2)
- Iron oxides (Fe2O3, FeO) – can contribute to the color variations.
Physical Properties:
- Density: Around 2500-2900 kg/m3 (depending on mineral composition and porosity).
- Solubility in Water: Low solubility in pure water. However, becomes more soluble in acidic environments.
- Melting Point: 849°C (1560°F) for calcium carbonate.
- Hardness: Varies depending on the specific type of limestone, typically ranges from 3 to 4 on the Mohs scale (calcite, the main mineral component, has a hardness of 3).
Safety Information:
- Limestone itself is generally considered non-toxic and non-hazardous.
- However, dust generated during crushing or processing can irritate the respiratory system.
- Wear a dust mask when working with crushed limestone.
- Be aware that some limestone formations may contain trace amounts of harmful minerals like silica or heavy metals depending on the location. Always refer to safety data sheets (SDS) for specific types of limestone being used in industrial applications.
