Nanometer calcium carbonate production and broad application prospects
Nano is the length of the unit of measurement for the 1 × 10-10m. Although the artificial manufacture of nano-materials can be manufactured from carbon black in China for thousands of years ago, counting paint, but the nano-particles of Germany was first developed in 1984, and created a precedent for human use nanotechnology. Nanoparticles is a new physical state, a material powder aggregate particle diameter less than 100nm, only in the electron microscope to observe the particle morphology.
In 1992, the international definition of nano-structured materials, nano-materials for the meeting: "two-phase materials in a phase of Renyi Wei in the 1-100nm size aggregates." 80 As the electron spectroscopy and scanning tunneling microscopy applications, a number of unusual properties of nano-particles were found, This world's scientific community and governments doubly hot area of concern. Nanoparticles compared with conventional particulate material has specific physical and chemical properties. Just 10 years, it has abroad of machinery, electronics, energy, chemical, biological, materials, defense and other fields to obtain a wide range of applications.
Nanotechnology is research and development of the world's hot spots, but nano-technology and materials in China is still at the initial stage, most of the results still remain in the laboratory, can industrialization only a few varieties of ultra-fine nano calcium carbonate is one of them.
Source of calcium because of a material easy to get lower prices, low toxicity, low pollution, high brightness, fill volume and mixing characteristics of good performance and processing, as in the amount of rubber processing one of the largest light-colored filling. However, due to its hydrophilic nature and the limitations of traditional production processes, usually calcium carbonate particles are relatively coarse, smaller than the surface area, the surface of a lack of activity, and polymer composites often played the role of incremental Tian Chong, the lack of reinforcement effect, applications can not fully play its role.
Nanometer superfine calcium carbonate is 80 years developed a new type of ultra-fine solid material. Particle size between 1-100nm, due to ultra-fine nano calcium carbonate particles, and its crystal structure and surface electronic structure changes, resulting in a common calcium carbonate do not have the quantum size effect, small size effect, surface effect and the macro- quantum effects, in magnetic, catalytic, light resistance and melting point compared with the conventional materials showed superior performance. To fill in the rubber, plastic products, the surface can Guangyan, good elongation, high tensile, tear resistant and strong resistance to bending, anti-cracking performance, is an excellent white reinforced materials. In the Advanced printing ink, coating with good gloss, transparency, stability, and quick-drying and other characteristics.
Nano-fine calcium carbonate can not only reduce the cost of capacity increase for the plastics, rubber and paper, it is also a reinforcing effect. Of calcium carbonate particle size less than 20nm products, the reinforcing effect and white carbon black equivalent of calcium carbonate particle size less than 80nm products, for automotive chassis rock attack paint. Therefore, the nano-level research and development of ultra-fine calcium carbonate and applications by domestic and international attention.
Nano calcium carbonate and calcium carbonate with ordinary light than ordinary calcium carbonate has the following characteristics:
(1) fine particles. The average diameter of 40nm, is the number of common light calcium carbonate particle size one-tenth;
(2) large surface area. Light calcium carbonate than the average nearly eight times as large;
(3) crystal is cube-shaped particles, some links in a chain, with the class structure, and spindle-shaped calcium carbonate and irregular-shaped calcium carbonate different;
(4) surface is activated, the activation rate was higher with different functions and purposes;
(5) high brightness, suitable for light products, pH, weakly alkaline.
Currently, the domestic research and production of nano calcium carbonate greater progress. Calcium carbonate production capacity is over 100,000 t / a of Baoxing calcium carbonate has recently launched three investment projects, of which 25 000 t / a calcium carbonate superfine powder project.
October 2000, Guangdong Yun Ping Kwong Ping Chemical Industry Co., Ltd. with Beijing University of Chemical Technology, "Synthesis of nano calcium carbonate gravity" built the world's first patented technology of a 3000t / a gravity industrialized nanometer calcium carbonate production line. The production line is running examination results show that the core equipment, stand-alone gravity carbonation reactor production capacity 3500t / a, exceeds the design capacity. After testing, the product performance to a British company ICI high car paint the SPT nano calcium carbonate quality index, exceeded the national chemical industry standard requirements of nanometer calcium carbonate, nano calcium carbonate production technology shows that China has been a world leader and Equipment level.
In addition, some foreign manufacturers are optimistic about calcium carbonate market in China, such as Spain Rebbert company also separately Zhanjiang, Guangdong, Nanjing Building Authority entered into a joint venture contract. Meanwhile, the British porcelain company in Anhui persons building a 20,000 t / a paper production plant using ultra-fine calcium carbonate and is prepared to build a set in Ningbo, 50,000 t / a unit.
Japan as early as four, took the lead in the fifties into nano calcium carbonate for industrial production, its products Baiyan Hua CC, CCR, and DD, have been successfully also used in rubber, plastics, ink, paper, paint and other industries. Japan nano technology, ultra-fine calcium carbonate in the international leading level, now spindle, cubic, needle-shaped, chain-shaped products such as nano-fine calcium carbonate and 50 kinds of modified products. Japan's application of nanometer calcium carbonate rubber are: industrial seals, automotive rubber parts, oil hose, water hose, white cot, black rubber roller, the soles of boots, white rubber shoes to help the whole color bicycle tires, red tire crown, white sidewall, sidewall rubber color, auto inner tubes (red, black) bike tread and so on. Nano calcium carbonate in the formulation of the filling of up to 100, equivalent to the proportion of rubber compound in 33%, both can be used alone, but also can adjust the recipe and used with other fillers to achieve the reinforcement, incremental, color, to improve the processing technology and product performance objectives.
Nano calcium carbonate domestic NBR, SBR applications a lot of work. Nano calcium carbonate used in that medium acrylonitrile content of NBR and SSBR the feasibility of oil. Nano calcium carbonate can replace some or most of the black and white black fabric for reinforcing filler, a filler large, strengthening and whitening effect is good, it is appropriate to promote the use of light-colored rubber products.
In recent years, as China's rubber, plastics, paper, paint and ink industry is developing rapidly, greatly promoted the consumption of calcium carbonate, in particular the production of high-level art paper, high-grade ink, auto paint (polyester paint the chassis, car paint, etc.) used in ultra-fine calcium carbonate nano-increasing market demand. However, there are nanometer superfine calcium carbonate production is still low, and less product variety, can not meet market demand, some products are also imported.
China is a common calcium carbonate production and export of a large country, the real import of calcium carbonate in China in 1999 about 89 600 t, the average price of 272 U.S. dollars / t, export calcium carbonate 22 400 t, the average price of 80 U.S. dollars / t, price difference of 192 per t dollars. 2000 China's import of calcium carbonate 56 200 t, the average price of 342 U.S. dollars / t, export of 31 200 t, the average price of 73 U.S. dollars / t. Although the reduction of imports, but low exports, high import situation had not improved, it is necessary to strengthen the intensity of research and development of high-grade calcium carbonate, to develop ultra-fine, ultra-pure nano-calcium carbonate and the promotion of rubber, plastic products, to whitewash materials, paints and other industrial products to high, precise sharp direction. At the same time the conditions for use of our abundant resources, the original manufacturer for the calcium carbonate production technology and process transformation, to improve calcium carbonate products, and increase added value.
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