What is the classification and function of stone?
There are two kinds of stone used for architectural decoration: natural stone and artificial stone, and natural stone is the main one. It belongs to high-grade decorative materials, mainly used for projects with high decorative grade requirements, while artificial stone belongs to low-grade decorative materials and is only used for middle and low-grade interior decoration projects.
Natural stone refers to materials mined from natural rock mass and processed into blocks or plates. There are two main kinds of stone materials used for architectural decoration: granite and marble.
The so-called marble refers to sedimentary rocks or metamorphic carbonate rocks, including marble, dolomite, limestone, sandstone, shale and slate. For example, the famous white marble in China is dolomite produced in Fangshan, Yunnan marble is marble produced in Dali County, and the famous Dandong Green is serpentine skarn. Similarly, all kinds of magmatic rocks mined as stone materials, such as granite, andesite, diabase, greenstone and gneiss, are called granite. For example, the white granite in Beijing Baihujian is granite, Jinan black is gabbro, and the black granite in Qingdao is diabase.
Artificial stone is a synthetic decorative material. According to the different binders used, it can be divided into organic artificial stone and inorganic artificial stone. According to the different production processes, it can be divided into four types: polyester artificial marble, composite artificial marble, silicate artificial marble and sintered artificial marble.
Among the four artificial stone decorative materials, organic (polyester) is the most commonly used and its physical and chemical properties are also the best.
Types and uses of building gypsum
The most commonly used gypsum in buildings is building gypsum, followed by model gypsum, high strength gypsum, anhydrous gypsum cement and floor gypsum.
The raw material for gypsum production is mainly natural gypsum dihydrate, also known as soft gypsum or raw gypsum, which is calcium sulfate containing two crystal waters. Natural gypsum dihydrate can be used to make gypsum with various properties.
The main processes of gypsum production are heating and grinding. Gypsum with different properties can be produced due to different heating temperatures and methods.
Building gypsum
Building gypsum is a white powder made of natural H-gypsum and other raw materials after calcination at 107℃ ~ 170℃ and then grinding. Its main component is B-type hemihydrate gypsum.
After the building gypsum is hardened, it has good heat insulation and sound absorption performance, good fire resistance and moisture absorption performance; The color is white, which can be used for indoor painting construction, especially suitable for making all kinds of. White, smooth and meticulous flower decoration, such as adding pigments, can make the products have various colors.
Building gypsum is not suitable for outdoor engineering and high temperature engineering above 65℃.
In a word, building gypsum can be used for indoor painting, making decorative products, porous gypsum products and gypsum boards.
(2) Plaster of Paris, which is calcined from gypsum dihydrate, is called model gypsum if its impurity content is less and its skin is thinner than that of white powder grinding. It solidifies faster and has higher strength than building gypsum. Mainly used for making models, sculptures, decorative flowers, etc.
(3) High-strength gypsum is made by putting H-type gypsum into an autoclave and steaming at 1.3 atmospheric pressure (124℃). A-type semi-hydrated gypsum powder has high strength after grinding. This kind of gypsum has high density and strength after hardening. High-strength gypsum is suitable for plastering engineering, decorative products and gypsum boards with high strength requirements. After adding waterproofing agent, its products can be used in high humidity environment. It can also be added into organic solution to make adhesive.
(4) Anhydrous gypsum cement
When natural gypsum dihydrate is heated to 400℃ ~ 750℃, gypsum will completely lose water and become insoluble anhydrite, and then an appropriate amount of activator is added and ground to obtain anhydrous gypsum cement. Anhydrous gypsum cement is suitable for indoor use, mainly used for making gypsum board or other products, and can also be used as indoor plastering.
(5) Floor gypsum
If natural gypsum dihydrate is calcined above 800℃, part of calcium sulfate is decomposed into calcium oxide, and the product after grinding is called high-temperature calcined gypsum, also known as floor gypsum. Floor gypsum has high strength, wear resistance and water resistance after hardening, so it is mainly used as gypsum floor for indoor ground decoration.