What Is Mineral Wool?

Mineral wool and its production are light, durable, non-combustible, non-rot, and free from insects, etc., and are excellent materials for thermal insulation and sound absorption. Cotton-like short fibers, including slag wool, rock wool, glass wool, and ceramic fibers, produced from silicate melts, generally refer to the first two in China. The earliest mineral wool obtained from the Hawaii Crater was called "Far's Hair". Those who use metallurgical slag or fly ash as the main raw material are called slag wool; those who use basalt and other rocks as the main raw material are called "rock wool". The raw materials are crushed into a certain particle size, and then additives are added for batching, and then they are melted in the furnace, turned into cotton, and packed. There are three types of cotton-making processes: spraying, centrifugal and centrifugal. Mineral wool and adhesives can be made into various mineral wool products through forming, drying, curing and other processes.

When mineral wool is prepared as a raw material, its acidic coefficient value MK value (ratio of SiO ₂ + Al ₂ O ₃ to MgO + CaO in weight percent) is generally controlled to be 1.2 to 1.6. When using natural rock as a raw material, an appropriate amount of flux should be added; when using metallurgical slag, an appropriate amount of acidic substance is often added. Hot air cupola is generally used as the melting equipment for rocks or slag, and it can also be used in pool kiln, electric furnace, etc. ^[1]

There are three main methods: injection, centrifugation and centrifugal injection. Spray method. It uses high-speed air or superheated steam at a certain pressure to split and blow the melt stream into fibers. According to the relative position of the stream and the airflow, it can be divided into vertical blowing method and flat blowing method, the fiber quality of the former is better than the latter. Centrifugation. It uses mechanical centrifugal force to spin the molten stream strands into fibers, often using multi-roll centrifuges. centrifugal injection method. The characteristics of centrifugation and spraying are combined. Mineral wool and binder are mixed in a certain proportion or the binder is sprayed during the formation of cotton, and then various mineral wool products can be made through the processes of molding, drying, and curing. Its main varieties are boards (also divided into rigid, semi-rigid and rigid), felts, blankets, pads, mats, strips, ropes and shells. Mineral wool products can be formed by dry method, wet method or semi-dry method according to their varieties and binders. The binders are divided into organic (such as synthetic resin, starch, asphalt, etc.) and inorganic (such as water glass, bentonite, kaolin, etc.). ^[1]

The production process of mineral wool began in the 1930s abroad. At that time, the steam jet method was used to blow the melt stream flowing out of the stream inlet with high-speed air flow and draw it into fibers. The fiber was thick and the fiber diameter reached More than ten microns, the content of impurities and slag balls is large, and the product quality is poor. Since the 1940s, people have continuously improved their mineral wool production technology, and have developed flat spraying, vertical spraying, disc centrifugation, and roller centrifugation. From the 70's to the 80's, internationally developed and matured common law production processes featuring cupola melting, four-roll centrifugal fiber formation, and settling cotton as the main features.

At present in China, the common law is still the dominant production technology and equipment. In the 1980s, on the basis of improving the melting and fiber-forming mechanism and replacing the set-up cotton collection technology with triangle net belt cotton collection and pendulum felt laying, the pendulum production technology was developed internationally. Under the same conditions as the common process production consumption, the pendulum method can produce high-quality products with long and thin fibers, few slag balls, high elasticity, high strength, low density and good feel, and improves common law mineral wool. The phenomenon of product layering. In China, only a rock wool company in Guangdong has adopted the pendulum production method, and its product quality is better than similar domestic products. In the ten years of the 1990s, the overall technical level of the pendulum production process in the world has made another leap (the pendulum method that can represent the world's most advanced technology level is temporarily called the advanced pendulum method. The previous pendulum method production The process is called primary pendulum method). The high-quality structural cotton produced by the advanced pendulum technology will give people a new concept. Its fibers are longer and finer, the content of slag balls is less, and the three-dimensional distribution of the fibers makes it have the same thermal insulation effect and the same

Mineral wool and its products have the characteristics of light weight, durable, non-combustible, non-rot, non-mildew, and free from insects, etc., and are excellent materials for heat preservation and sound absorption. The fiber diameter of mineral wool should be no more than 9 microns; the content of slag balls should not exceed 10%. The bulk density of raw cotton is 50-100 kg / m3, while the bulk density of products varies depending on the variety. The felt is 40-200 kg / m3, and the board is 70-500 kg / m3. The thermal conductivity of mineral wool and products at room temperature is generally 0.041 to 0.07 W / (m · K). Use dry method

With the country's emphasis on energy conservation and environmental protection requirements, the mineral wool veteran has played a major role in the new industry. In the current building insulation, the application of mineral wool is also very popular, especially in the past few years, fires using polystyrene foam board insulation mode have occurred from time to time, the building insulation industry has always attached great importance to the selection of insulation materials. Mineral wool can have good incombustibility due to its thermal insulation effect. It is increasingly used in the building insulation industry. Professor Tian Yanfeng, who has been committed to building insulation, said as far back as 2000: The application technology is the key research and development of the building energy saving industry. "

There are two main types of mineral wool construction in building energy conservation, one is dry hanging, and the other is pasting. Dry hanging is mainly used for supporting building exterior glass curtain walls, stone curtain walls, etc., which are used as filling insulation materials in the keel. Pasting is similar to the construction of polystyrene sheet. Since the weight of mineral wool board is heavier than that of polystyrene board and the internal strength is slightly worse, there are a few points to note in the construction. First, galvanized wire mesh must be used for protection, and To use thermal insulation nails to fix, for mineral wool products with large weight, also consider the construction process to avoid deformation caused by excessive weight. ^[2]

Dry hanging rock wool ^[3]

Rock wool board