Hydrated lime, is also known as calcium hydroxide. Hydrated lime is obtained by the reaction of quicklime – calcium oxide – with water producing a dry, white powder that is highly alkaline. Hydrated lime is used in a variety of industries and in environmental areas because of its versatility of uses it has become as fundamental Hydrated lime can be used in almost every industrial field and is environmentally friendly.
Physical as well as Chemical characteristics
- Appearance: Fine, dry white powder
- Solubility: Very slowly soluble in water, liberating a basic solution which is known as limewater
- pH: Alkaline, when dissolved in water it will exhibit a pH value 12.4
- Reactivity: Reacts readily with acids and many other compounds
- Density: Technically it is relatively low density for ease of handling, transportation etc
Uses of Hydrated Lime
Calcium hydroxide is used in numerous ways in various fields. Some of the most significant uses include:
1, Water Treatment
Being an essential industrial material for water treatment, hydrated lime is quite fundamental in both municipal & industrial water treatment. Its high alkalinity allows it to:
- Neutralize acidity in water, enhancing the pH level of water and making the water safe for human consumption.
- Precipitate impurities like heavy metals, phosphates and suspended solids so that they can be more easily eliminated.
- Softening water by removing the concentration of calcium and magnesium ions, which cause hardness in water.
2, Construction Industry
In the construction sector, hydrated lime is used as a key ingredient in several building materials and processes:
- Mortar and Plaster: Builder’s lime is blended with sand and cement, and it offers extra flow and plasticity in the preparation process making it easier to apply. From its physical properties, it is quite apparent that lime mortar has much more flexibility and breathability when used compared to more rigid cement mortar and for this reason, lime mortar is favored in the restoration of buildings with historical significance.
- Soil Stabilization: It is used to enhance the engineering characteristics of soil especially in making construction of roads. Hydrated lime with the clay particles of the soil tends to decrease the plasticity, increases the strength and load bearing capacity of the soil.
- Concrete Additive: Hydrated lime is used in combination with concrete to increase the concrete’s strength and performance and to overcome effects of shrinkage.
3, Environmental Protection
Hydrated lime is frequently used to help mitigate environmental impacts and for pollution control:
- Flue Gas Treatment: In power stations and other industrial establishments, the product is used to eliminate acidic gases [for instance, sulfur dioxide SO 2 )] from the exhausts. One technique called flue gas desulfurization minimizes these emissions which cause acid rain.
- Wastewater Treatment: Industrial wastewater contains heavy metals that are hazardous to the environment, although hydrated lime is useful in pH correction and removal of such metals in industrial water.
- Soil Remediation: They use it to remove the pH in acidic soils and precipitate other heavy metals for disposal, rendering soil safe for agricultural or construction purposes.
4, Agriculture
In agriculture, hydrated lime serves multiple purposes:
- Soil pH Adjustment: Hydrated lime is widely used to reduce the acidity levels of acidic soils to encourage plant growth. The increased use of the compound to the water results in improved capability of the plant to address its elemental requirements of nitrogen, phosphorus, and potassium.
- Animal Waste Management: It is also employed in pastoral industry to neutralize animal waste since it reduces smell, controls pathogen and hinders ammonia formation.
5, Food Industry
Surprisingly, hydrated lime finds application in the food industry as well:
- Food Additive: In moderate quantities, hydrated lime is employed in food processing as a food enhancer E526 for example in nixtamalization of corn whereby the outer layers of corn kernels are removed and the availability of nutrients improved.
- Beverage Clarification: It is also employed in the clarification of sugar and other beverages to get rid of both colours and other unpleasant materials.
6, Paper and Pulp Industry
In the paper and pulp industry, hydrated lime is also used in the Kraft process for regeneration of chemicals used in pulping of the liquors. In this case it assists in the preparation of white liquor which is an important chemical for conversion of wood to fibers in production of paper.
Benefits of Hydrated Lime
- Versatility: Hydrated lime can literally be used anywhere and is used in and across nearly every industry, making it amongst the most popular chemicals.
- Cost-Effective: It is affordable and readily available thus enabling the industries to reduce their operating expenses.
- Sustainability: Exhausting lime can also be prepared and is normally utilized to neutralize the effects of the environment on industries.
- Safety: Used appropriately, the product provides an efficient and safe way of treating water, waste and soil.
Conclusion
Hydrated lime is used across various industries, including construction and environmental care industry. Water treatment, agriculture, and pollution control cannot be easily managed without the assistance of its capacity to neutralize, bind, and stabilize.