In construction and renovation projects, we often use three materials: quicklime, gypsum and hydrated lime. They are very similar in appearance, but they are very different in nature and use. Therefore, it is very important to distinguish between these three materials correctly. Below, I will introduce you to several ways to quickly distinguish quicklime, gypsum, and hydrated lime.
Quicklime, also known as burnt lime, is mainly composed of calcium oxide (CAO), which is usually calcined by calcining natural rocks with calcium carbonate at high temperatures to decompose carbon dioxide and calcium oxide. Quicklime is a commonly used building material and an important chemical raw material, which has a wide range of applications in construction, metallurgy, chemical industry, environmental protection and other fields.
Hydrated lime, also known as slaked lime, the main component is calcium hydroxide (Ca(OH)2), which is a white powdery solid, slightly soluble in water, and its aqueous solution is often called lime water. Industrially, hydrated lime can be used to make bleaching powder, sodium hydroxide, sodium silicate, etc.;In agriculture, hydrated lime can be used to improve acidic soils, prepare Bordeaux liquid, etc.;In life, hydrated lime can be used for disinfection, stain removal, etc.
Gypsum, also known as raw gypsum, is a monoclinic mineral composed of calcium sulfate hydrate as the main component, which is widely used in human production and life. Gypsum is a common mineral, generally white or gray, red, brown, mainly distributed in North America, Europe, Asia, Africa and Australia. Gypsum can be divided into raw gypsum (calcium sulfate dihydrate), anhydrite (anhydrous calcium sulfate) and hemihydrate gypsum (calcium sulfate hemihydrate) according to its composition. After heating and calcination, raw gypsum can be prepared into anhydrite and semi-hydrated gypsum. In the field of building materials, gypsum can be directly used as a building bonding material, and can also be decorated on interior walls and ceilings, and the ceiling and wall decoration made of it have a variety of functions such as fire prevention, sound insulation, and heat preservation. In medical treatment, plaster is often used for diseases such as broken bones and fractures, and the use of plaster to fix the affected area can effectively promote. In the field of art, it has been used as a sculptural material by a variety of cultures, including ancient Egypt, Mesopotamia, ancient Rome, the Byzantine Empire, and medieval England.
1. Observe the appearance: the appearance of quicklime is generally white or off-white lumpy substance, and there are some pores on the surfaceThe appearance of gypsum is generally white or off-white powdery substance, and the texture is relatively delicate;The appearance of hydrated lime is generally white or off-white powdery substance, and the texture is relatively coarse.
2. Water addition reaction: add quicklime, gypsum, and hydrated lime to an appropriate amount of water respectively to observe their reactions. When quicklime is added to water, it will quickly produce a large amount of heat and produce a large amount of water vapor, while the solution will become turbid;When gypsum is added to water, it will gradually expand and produce a small amount of heat, while the solution will become more turbidWhen hydrated lime is added to water, it does not produce significant heat and water vapor, and the solution becomes clearer.
3. Chemical detection: chemical reagents can be used to detect quicklime, gypsum, and hydrated lime. For example, quicklime and hydrated lime can be detected using phenolphthalein reagent, which turns red when exposed to phenolphthalein reagent, while hydrated lime does notGypsum can be detected using hydrochloric acid reagents, which produce a large number of bubbles when exposed to hydrochloric acid reagents.
4. Classification of uses: quicklime is often used in building materials, desiccant, desulfurizer and other fieldsGypsum is often used in building materials, sculpture, model making and other fields;Hydrated lime is often used in architectural coatings, sewage treatment, soil improvement and other fields.
In conclusion, quicklime, gypsum, and hydrated lime can be quickly distinguished by methods such as observation of appearance, water addition reaction, chemical testing, and use differentiation. When working with these materials, be sure to pay attention to their sexuality.