The company's products are widely used in paper, rubber, plastics, coatings, building materials and other fields, but also according to customer requirements, the production of customer demand products. The company uses the advantages of local high-quality limestone and water resources to produce "Shiyuan Brand" calcium hydroxide and calcium oxide, dominated by special low-lead calcium hydroxide, which is mainly used in medicine, food industry, sewage treatment, acidic water neutralization treatment, flue gas desulfurization, garbage incineration, coatings, building materials, leather and other fields.
Lime has quicklime and hydrated lime. The main component of quicklime is calcium oxide (CaO), white solid refractory insoluble. Limestone with high (CaO) content is calcined to above 900 ℃ in a ventilated lime kiln. Is a water absorption, can be used as a desiccant, China's folk commonly used to prevent debris moisture. Reacts with water (while releasing a lot of heat), or absorbs moisture in humid air, which becomes hydrated lime [calcium hydroxide Ca(OH)2, also known as "hydrated lime". Hydrated lime in a liter of water dissolved 1.56 grams (20 ℃), its saturated solution called "lime water", alkaline, in the air to absorb carbon dioxide and calcium carbonate precipitation.
transformation and hardening with slaked lime
The process by which quicklime (CaO) reacts with water to produce calcium hydroxide is called slaking or digestion of lime. The reaction product calcium hydroxide is called slaked lime or slaked lime.
When the lime is slaked, a large amount of heat is released, and the volume increases by 1-2.0 times. The lime with good calcination and high calcium oxide content is slaked faster, and the heat release and volume increase are also more. There are two common methods for slaking lime on the construction site: slaked lime slurry method and slaked lime powder method.
In the lime slurry formed after the slaking of quicklime, the lime particles form calcium hydroxide colloid structure, the particles are very fine (particle size is about 1μm), and the specific surface area is very large (up to 10 ~ 30m 2/g). The surface adsorbs a thick water film, which can adsorb a large amount of water, so it has a strong ability to retain water, that is, good water retention. Mixing it into cement mortar and mixing mortar can significantly improve the workability of mortar.
Lime is hardened by drying crystallization and carbonization. Due to the low content of carbon dioxide in the air and the hard shell of calcium carbonate formed after carbonization, it prevents carbon dioxide from penetrating into the interior and prevents water from evaporating outward, thus hardening is slow and the strength after hardening is not high. The compressive strength of 1:3 lime mortar 28d is only 0.2-0.5MPa. In a humid environment, the water in the lime does not evaporate, carbon dioxide can not penetrate, hardening will stop; plus calcium hydroxide slightly soluble in water, the hardened lime will dissolve and collapse when it meets water. Therefore, lime should not be used in a long-term humid and water-soaked environment.
Lime in the hardening process, to evaporate a large amount of water, causing significant volume shrinkage, prone to dry shrinkage cracks. Therefore, lime should not be used alone. Generally, it should be mixed with materials such as sand, paper tendons, hemp knives, etc. to reduce shrinkage, increase tensile strength, and save lime.
Lime has a strong alkaline, at room temperature, can react with the glassy active silica or activated alumina to generate a hydraulic product, resulting in cementation. Therefore, lime is also an important raw material in the building materials industry.
