Application Of Limestone powder

 Limestone is a common non-metallic minerals. Limestone rich in mineral resources in China, accounting for 64% of the world's total reserves of more than an advantage of natural resources. More developed countries in foreign countries, such as Japan, the United States in the limestone and deep processing results using numerous, 400 to 500 patents. High-grade calcium carbonate as foreign materials, packing into the Chinese market, and promote domestic technological progress and speed up the processing of calcium carbonate species of rapid growth, and toward diversification, specialization, and refinement of the direction of rapid development, expanding open more

 Applications.

 A wide range of uses of limestone use of limestone, market prospects, but because the amount of limestone rich in a wide range of China, no local resources at all, must rely on strength and other advantages to gain market share. Therefore, in the face of this resource, in the development and application should be carefully chosen, taking the shortest of the process, most likely the simplest way, the most realistic market to low-cost, high-quality, increase market competitiveness. Limestone products, deep processing and foreign development status, introduced several main purposes of limestone.

 Physical processing

 (1) The most common is the production of Portland cement. Generally crushed limestone, after grinding raw materials can meet the requirements of the cement. With the opening up of the acceleration of national economic construction, the cement industry developed rapidly, it is estimated that the next 20 years alone the domestic cement industry will demand a limestone 29 billion t.

 (2) production of high-grade paper with a coating grade calcium carbonate product. Such high value-added fine, fine and heavy calcium carbonate in the papermaking process is widely used, after crushing the general size - 2μm ≥ 90% for neutral sizing papermaking process; - 2μm diameter ≥ 50% of the filler is mainly used for coated paper.

 (3) for plastics, coatings and other production processes in the filler. Natural raw materials such as calcium carbonate minerals, including requirements that the limestone CaCO3 (dry): 9810% superior grade, Grade 9610%, Grade 9410%, Fe2O3 ≤ 011%, Mn ≤ 0102%, Cu ≤ 01001%, whiteness of 90 or more. In addition, the general average particle size of 10 ~ 15μm powder ore used as paint filler, - 10μm for use as plastics, rubber, paper filler, - 5μm made after the ink by the activated filler.

 (4) production machinery for manufacturing of foundry sand. The production of cast limestone sand, 28 to 75 degree head, this sand has a better than the performance of quartz sand, collapsibility, and easy to clean off the sand, improve casting surface quality and increase the casting surface finish, and basically eliminate the hazards of silicosis workers . According to statistics, every year only major steel company purchased several tons of foundry sand, which is limestone metallurgical industry is a potential market.

 (5) production of desulfurization absorbent. Limestone crushing to 0 ~ 2mm, which + 2 mm <5%, 0 ~ 0. 45 mm> 50% of the powder instead of the original lime or hydrated lime, in the absorption tower with water into a slurry mixing, slurry and gas exposure absorption mixed, the sulfur dioxide in flue gas and the slurry of calcium carbonate and the drum into the air for chemical reaction is removed, the final reaction product is gypsum. After the heated flue gas desulfurization after warming up into the chimney. The maturation process equipment, desulfurization efficiency, and wide application. Guizhou Aluminum Plant currently has built a limestone limestone desulfurization agent in the production line, its effectiveness is very good.

 (6) limestone by calcination, carbonation can produce PCC products. Average particle size of calcium carbonate can be divided into five levels of granularity: particles + 5μm, powder 1 ~ 5μm, fine 011 ~ 1μm, ultra-fine 0102 ~ 011μm, ultra-fine - 0102μm. At present industrial production of nano-scale light calcium in Guangdong, Shanghai, Zhejiang and other places has been one after another. Can be divided by product crystal sphere, spindle-shaped, cubic, chain-shaped, sheet-shaped, diamond-shaped. Cubic, spherical calcium carbonate is more suitable for the plastics industry.

 (7) for the production of lime, lime passivation. Production of lime calcined limestone and lime through the passivation processed produce. Passivated with lime to absorb moisture, and good injection performance. These two products are mainly used in the metallurgical industry sinter additives, steel slag forming agent used in hot metal pretreatment with the desulfurization, dephosphorization agent, and according to initial liquid steel components and finished products after refining the specifications, design out the different uses of the refining slag and steel and other adjustments based on a variety of mold powder and so on. Currently still in the initial stage of hot metal pretreatment, only a few mills off the implementation of the three desulfurization, dephosphorization, from silicon, most of the steel yet for hot metal pretreatment. However, Japan, the United States and other more developed countries metallurgy of hot metal pretreatment has reached more than 80%, is expected within 5 ~ 10 a hot metal pretreatment of domestic steel mills will have greater development, CaO and CaCO3 are a variety of metallurgical charge The basic components, so in charge of the development process of metallurgical limestone will also have better development prospects. Chemical processing of limestone chemically processed to produce light calcium phosphate, oral calcium (pharmaceutical grade), the food industry calcium additives, toothpaste, baking powder and high friction, feed additive, phosphate, and calcium lactate, calcium gluconate, chloride and calcium carbide (calcium carbide) and so on.