Calcium hydroxide
Description
Calcium hydroxide (CAS 1305-62-0), commercially known as slaked lime or hydrated lime, is a strong inorganic base used across food processing, water treatment, construction, and agriculture.
As E526, it functions primarily as a pH regulator, firming agent, and alkali source in both industrial and food-grade applications. In food processing, it is used to nixtamalize corn for tortilla production.
It is also utilized to firm fruit and vegetable textures in pickling and canning. Water treatment plants rely on it to adjust pH, precipitate heavy metals, and soften hard water through controlled coagulation and flocculation.
In construction, it is a core component of mortars, plasters, and soil stabilization projects where controlled alkalinity improves structural binding. Pulp and paper producers use it in causticizing processes.
This process helps to regenerate sodium hydroxide from green liquor, making it integral to the kraft pulping cycle. The material is supplied as a dry white powder, with bulk availability in bags and super sacks.
Standard grades include food-grade (FCC, E526-compliant), USP, and technical or industrial grade. Purity levels and particle size distributions vary significantly depending on the specific grade required.
Food and pharmaceutical grades are held to tighter specifications than construction or agricultural material. This ensures compliance with global safety and quality standards for sensitive manufacturing applications.
Physical Properties
| Melting Point | 580 °C (decomp) |
| Boiling Point | 2850 °C |
| Density | 2.24 g/cm³ |
| Appearance | Calcium hydroxide is a soft white crystalline, odorless powder with an alkaline, bitter taste. |
| Color | White |
| Odor | Odorless |
| Form | Solid |
| Water Solubility | 1.65 g/L (20 ºC) |
| Refractive Index | 1.574 |
| pH | 12.6 (H2O, 20℃)(saturated solution) |
Safety & Handling (Learn More)
Trade & Regulatory
| HS Code | 28259099 |
| Storage Class | 13 - Non Combustible Solids |
| WGK (Germany) | 1 |
Documentation
Other Names
slaked lime|Hydrated lime|hydralime|Caustic lime|Calcium hydrate|Ca(OH)2|builders' lime|Lime hydrate|E526
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