About Hydrated Lime

Hydrated Lime, also known as calcium hydroxide, slaked lime, or builders’ lime, is an inorganic compound with the chemical formula Ca(OH)₂. It appears as a white, odorless powder with a slightly alkaline taste and is sparingly soluble in water, forming a solution commonly known as limewater. Hydrated lime is produced through the controlled slaking process, which involves adding water to quicklime (calcium oxide) in a highly exothermic reaction. This hydration process converts the oxide to hydroxide, releasing significant heat and expanding in volume. The resulting product is then dried and milled to produce fine powder with consistent particle size and high surface area.

Hydrated lime’s alkalinity, reactivity, and ability to neutralize acids make it one of the most versatile and economically important industrial alkalis. Its applications span from construction and agriculture to environmental remediation and chemical manufacturing. Major sectors utilizing hydrated lime include construction and building materials, water and wastewater treatment, steel and metallurgy, agriculture and soil conditioning, chemical manufacturing, and environmental control. The compound’s natural origin, effectiveness, and relatively low cost have established it as an essential material in both traditional and modern industrial processes worldwide.

Hydrated Lime Uses

Construction and Building Materials

Hydrated lime is extensively used in construction applications, particularly in the production of mortar, plaster, and stucco. It improves workability, water retention, and bonding properties of cement-based mixtures, creating more durable and flexible construction materials. In masonry mortar, hydrated lime enhances plasticity and allows for easier application while reducing cracking caused by shrinkage or movement. It is a key component in lime plaster and lime render used in both new construction and historic building restoration, valued for its breathability and compatibility with traditional building materials. Hydrated lime is also incorporated into soil stabilization for road construction and foundation work, where it improves the load-bearing capacity and reduces plasticity of clay soils. Additionally, it is used in the manufacture of calcium silicate bricks, autoclaved aerated concrete, and as a component in asphalt production.

Water and Wastewater Treatment

In water treatment applications, hydrated lime serves as a primary chemical for pH adjustment, water softening, and coagulation processes. It neutralizes acidic water, raises pH to optimal levels for disinfection and corrosion control, and precipitates hardness-causing calcium and magnesium ions to produce softer water suitable for industrial and municipal use. Hydrated lime is employed in clarification processes where it aids in removing suspended solids, heavy metals, and other impurities through precipitation and coagulation. In wastewater treatment, it neutralizes acidic industrial effluents, removes phosphorus through chemical precipitation, and facilitates sludge conditioning for improved dewatering. The compound is also used in drinking water treatment for pathogen inactivation, taste and odor control, and maintaining stable water chemistry in distribution systems.

Steel Manufacturing and Metallurgy

Hydrated lime plays a critical role in steel production and metallurgical processes. In basic oxygen furnaces and electric arc furnaces, it is used as a flux to remove impurities such as silica, sulfur, and phosphorus from molten iron, forming slag that can be separated from purified steel. The alkalinity of hydrated lime neutralizes acidic impurities and helps control the chemistry of the steelmaking process, improving final product quality. In sintering plants, lime is added to iron ore to improve sinter quality and permeability. The metallurgical industry also utilizes hydrated lime in non-ferrous metal refining, including copper, zinc, and gold processing, where it adjusts pH in flotation circuits, precipitates impurities, and neutralizes acidic solutions. Additionally, it is employed in flue gas desulfurization systems at steel plants to remove sulfur dioxide emissions.

Agriculture and Soil Treatment

Hydrated lime is utilized in agriculture for soil pH modification and improvement of soil structure and fertility. It neutralizes acidic soils, raising pH to levels optimal for crop growth and nutrient availability. By adjusting soil pH, hydrated lime improves the effectiveness of fertilizers and reduces aluminum and manganese toxicity that can inhibit plant growth in acidic conditions. The compound supplies calcium, an essential plant nutrient, supporting cell wall development and overall plant health. In livestock operations, hydrated lime is applied in barns, poultry houses, and animal facilities for sanitation and odor control, where its alkalinity helps neutralize acidic waste and reduce pathogen populations. It is also used in composting operations to accelerate decomposition, control pH, and reduce odors during the composting process.

Chemical Manufacturing and Industrial Applications

Hydrated lime serves as a key raw material and reagent in numerous chemical manufacturing processes. It is used in the production of calcium-based chemicals including calcium stearate, calcium hypochlorite, and precipitated calcium carbonate. In the petroleum refining industry, hydrated lime neutralizes acidic compounds in crude oil and refinery streams. The pulp and paper industry employs hydrated lime in kraft pulping processes for cooking liquor preparation and in causticizing operations to regenerate sodium hydroxide from sodium carbonate. Hydrated lime is essential in flue gas treatment systems for removing sulfur dioxide, hydrogen chloride, and other acidic gases from industrial emissions, supporting environmental compliance. In leather tanning, it is used for dehairing hides and adjusting pH during various tanning stages. The sugar industry utilizes hydrated lime in sugar refining to purify sugar juice and remove impurities. Additionally, it finds applications in mining operations for pH control in ore processing, in the manufacture of rubber and plastics as a processing aid and filler, and in various environmental remediation projects for neutralizing acidic contaminated sites and stabilizing hazardous waste.

Hydrated Lime Supplier Australia, USA & More!

Redox are trusted, authorised suppliers of Hydrated Lime. With distribution centres worldwide, we can supply to Australia, USA, UK, NZ, Europe, Asia and more. Get in touch with our expert team, who can help you order the right product, form and amount for your needs.