Bag
Small-volume and retail shipping in 25 kg kraft bag packaging.
Ca(OH)₂ — Calcium Hydroxide
Hydrated Lime
Industrial Solutions
Hydrated lime (calcium hydroxide, Ca(OH)₂) is an inorganic compound in the form of a fine, white powder obtained by the controlled reaction of quicklime with water. It is a critical industrial raw material in dozens of different sectors, most notably water treatment, construction, agriculture and flue gas desulphurisation.
Formula
Ca(OH)₂
pH Value
12.4 – 12.6
CaO + MgO
≥ 90%
Standard
TS EN 459-1
Definition and Production Process
What Is Hydrated Lime (Calcium Hydroxide)?
Hydrated lime is produced by the exothermic reaction of calcium oxide (quicklime, CaO) with water. A significant amount of heat is released during this reaction, and the product is transformed into a fine, white powder form known as "hydrated lime" or "calcium hydroxide".
In the production process, high-purity limestone (CaCO₃) used as raw material is first converted into quicklime by calcining it at 900-1100 °C in rotary or shaft kilns. Hydration is then carried out by the controlled addition of water in slaking units.
The temperature, water ratio and mixing speed of the slaking process directly determine the particle size, reactivity and purity level of the final product. In industrial facilities, continuous slaking lines are used to obtain a product of homogeneous quality.
Chemical Reaction Equation
CaO + H₂O → Ca(OH)₂ + Heat
~65 kJ/mol of energy is released. High-purity limestone (CaCO₃) is used as the raw material.
Technical Data
Physical and Chemical Properties
The fundamental parameters that determine the industrial value of hydrated lime are defined within the framework of the TS EN 459-1 standard.
| Parameter | Value / Range | Description |
|---|---|---|
| Chemical formula | Ca(OH)₂ | Calcium hydroxide |
| Molecular weight | 74.09 g/mol | — |
| Specific gravity | 2.20 – 2.45 g/cm³ | Particle density |
| Bulk density | 0.30 – 0.60 g/cm³ | Bulk density (in powder form) |
| Water solubility (20 °C) | ~1.5 g/L | Decreases as temperature rises |
| pH value | 12.4 – 12.6 | Strongly alkaline character |
| CaO + MgO content | ≥ 90% (typically >93%) | TS EN 459-1 compliant |
| CO₂ content | ≤ 7% | Low carbonation |
| Fineness (below 90 µm) | ≥ 93% | High specific surface area |
| Colour | White | Indicator of purity |
Packaging Options
Shipping and Delivery Options
Our products are shipped in bag, bigbag and bulk tanker (granular and powder) forms.
Bigbag
Industrial packaging with 1-tonne capacity providing ease of handling.
Bulk Tanker
Direct silo-to-silo pressurised transfer for granular and powder products.
In-Depth Information
From Production to Shipment: The Hydrated Lime Chain
Hydrated lime (calcium hydroxide, Ca(OH)₂) is the final link in a production chain that starts with limestone. To understand the quality of the product, it helps to look at what changes at each step of the chain and what the parameters on the certificate of analysis mean. The sections below answer these questions with our own calculations and our statements about our plants.
How does the mass change along the production chain?
Assuming pure substances, 100 kg of limestone (CaCO₃) decomposes in calcination into 56.0 kg of quicklime (CaO) and 44.0 kg of carbon dioxide. When 56.0 kg of CaO is slaked with 18.0 kg of water, 74.0 kg of hydrated lime is formed.
| Step | Reaction | In | Out |
|---|---|---|---|
| Calcination | CaCO₃ → CaO + CO₂ | 100 kg CaCO₃ | 56.0 kg CaO + 44.0 kg CO₂ |
| Hydration (slaking) | CaO + H₂O → Ca(OH)₂ | 56.0 kg CaO + 18.0 kg water | 74.0 kg Ca(OH)₂ |
| Overall | CaCO₃ → Ca(OH)₂ | 100 kg CaCO₃ | 74.0 kg Ca(OH)₂ |
These values are our own stoichiometric calculation; the actual yield depends on the purity of the raw material and on the burning and slaking conditions. Impurities in the limestone directly lower the Ca(OH)₂ content of the product.
What do the quality parameters mean?
The quality of a batch is not judged by a single value but by reading the parameters on the certificate of analysis together.
| Parameter | What it shows | Why it matters |
|---|---|---|
| Ca(OH)₂ content | The reactive share of the product | Directly affects dosing; the lower it is, the more product is needed for the same effect |
| CaO + MgO | Total oxide equivalent | An indicator of overall purity |
| CO₂ | Degree of carbonation by CO₂ in the air | The carbonated part is no longer active |
| Fineness (below 90 µm) | Share of particles passing the sieve | A finer product has a larger surface area and reacts faster |
| pH | Alkalinity in an aqueous medium | Shows neutralising strength |
The building lime standard EN 459-1 divides air limes into the classes CL 90, CL 80 and CL 70 according to their CaO + MgO content, and sets separate limits for parameters such as CO₂ and available lime (Ca(OH)₂ in the case of hydrated lime). Which class a product falls into is determined only by the certificate of analysis and the current text of the standard. We explain how to read the certificate in our bulk hydrated lime buying guide.
Hydrated lime or quicklime?
Both are made from the same limestone. Quicklime reacts violently and exothermically with water and requires slaking equipment where it is used; hydrated lime is a ready-to-use powder. When 1 kg of quicklime is slaked, it theoretically yields about 1.32 kg of hydrated lime. For a decision table, see our comparison of quicklime and hydrated lime.
Our plants and shipment
Vişne Madencilik was founded in 1952 as a small limestone quarry in Bergama. Today it operates three integrated plants: Çelemli (Yüreğir, Adana), Narlı (Pazarcık, Kahramanmaraş) and Çukurova / Gündoğan (Ceyhan, Adana). The Lime Slaking Facility and Packaging Unit at Narlı opened on 17 April 2025. The company states that its combined quicklime capacity exceeds 2,250 tonnes per day and that it exports to more than 30 countries. Hydrated lime is shipped in 25 kg kraft bags, in 1-tonne big bags or in bulk by silo tanker. For details, see our factories page.
Safe handling and storage
Hydrated lime dust can irritate the skin, eyes and respiratory tract. The product should be kept closed and dry, because it reacts with carbon dioxide in the air and loses its activity. For dosing, milk of lime preparation and unloading, see our usage guide; for safety information, always rely on the product's safety data sheet (SDS).
Industrial Use
Application Areas
Calcium hydroxide is a versatile raw material used across a wide industrial range.
Water and Wastewater Treatment
It is a fundamental chemical for pH adjustment, water softening and heavy metal precipitation in drinking water and industrial wastewater treatment plants. By raising the pH to the 9.5-11 range, it enables the precipitation of heavy metals such as zinc, copper, chromium and lead.
pH 9.5 – 11Construction Industry
It is used in lime plaster, lime mortar and whitewash. It acts as a plasticiser in cement mortars and, thanks to its disinfectant properties, is preferred in the production of hygienic whitewash. It serves as a reactive component in the production of autoclaved aerated concrete (AAC).
AAC ProductionAgricultural Applications
It is widely used to neutralise acidic soils. By raising the soil pH, it increases the availability of plant nutrients such as phosphorus and molybdenum. It is also used for barn disinfection in livestock farming.
Dose set by soil analysisFlue Gas Desulphurisation (FGD)
It is a critical sorbent material for removing acid gases such as SO₂ and HCl in thermal power plants, cement factories and waste incineration facilities. It is used in dry sorbent injection (DSI) and semi-dry methods.
Acid gas sorbentFood and Chemical Industry
Food-grade calcium hydroxide (E526) is used in sugar refining, pickle and olive processing, nixtamalization and water pH stabilisation. In the chemical industry, it serves as an intermediate in the production of sodium hydroxide.
E526 ApprovedApplication Guide
Points to Consider During Use
The following technical considerations should be observed for the effective and safe use of hydrated lime.
Storage Conditions
Calcium hydroxide reacts with CO₂ in the air, carbonates and loses its effectiveness over time. It should be stored in enclosed, dry environments protected from air circulation.
Dosage Control
Overdosing may cause the pH to exceed the target. Dosing with automatic pH control systems is recommended.
Particle Size and Reactivity
The fineness of the product directly affects the reaction rate. While products with d₉₀ < 10 µm are preferred in flue gas treatment, coarser-grained products are sufficient for agricultural liming.
Occupational Safety
Hydrated lime dust is irritating to the skin, eyes and respiratory tract. Dust exposure limits (TLV-TWA: 5 mg/m³) must be observed and appropriate PPE must be used.
Quality Standards
Compliance with TS EN 459-1 for building lime, TS EN 12518 for water treatment chemicals and E526 regulations for food-grade uses should be required.
FAQ
Frequently Asked Questions
The most frequently asked technical and application-related questions about hydrated lime.
Let's Find the Right Solution for Your Project Together
Get in touch with our technical team for your hydrated lime needs. We offer our quality assurance with TS EN 459-1 compliant analysis certificates.