What is blockchain PCC

1. Sharing invitation code: 1443

2. In a narrow sense, blockchain is a kind of chained data structure that combines data blocks in chronological order in a way of sequential connection, and it is a distributed account book that can not be tampered with and forged by cryptography. In a broad sense, blockchain technology is a new distributed infrastructure and computing paradigm, which uses blockchain data structure to verify and store data, uses distributed node consensus algorithm to generate and update data, uses cryptography to ensure the security of data transmission and access, and uses intelligent contract composed of automated script code to program and operate data
nowadays, the mainstream digital currencies are basically developed based on blockchain technology. Blockchain is the underlying technology of digital currency. The domestic tea based digital currency Puyin is developed based on blockchain technology.

3. PCC, a shapable pigment, precipitated calcium carbonate (PCC) has been identified as the future carbonate pigment. Its bright spot and purity are incomparable. There are many kinds of procts that can be used to ensure that any problems encountered by paper workers can be solved by PCC. PCC is a kind of precipitated calcium carbonate, whose form is bright crystal. The raw materials of PCC are usually quicklime (CAO) and carbon dioxide (CO2). The first step in proction is to ripen, that is, to mix quicklime with a large amount of water. Cao reacts with water to form calcium hydroxide, which is sent to the reactor as slurry. In the reactor, calcium hydroxide is mixed with the gas containing CO2, and PCC is precipitated. After the reaction, the solid content of slurry PCC is 18-25%. After screening, the mercury is sent to the storage tank for use as the filler of papermaking. High solid content is required for paper coating, so PCC slurry should be dehydrated to 70-72% solid content. The dehydrated PCC is redispersed by agitator, and only dispersant is added in the process of agitating without adding water. The redispersed PCC was screened for coating. Most of the world's PCC is prepared in the subsidiary workshop, which is adjacent to the paper mill. The subsidiary workshop accepts the flue gas from the paper mill as the source of CO2. The advantage of this idea is that the final proct of PCC is sent directly to the storage tank of the paper mill. A modern PCC workshop can proce many different procts. It is important that every proct that can be proced has no change in particle size, brightness, etc. If the proct quality is consistent in the long run, the paper mill will benefit a lot by using PCC (as filler or coating pigment). Modern proction technology can ensure the constant quality. PCC and ground calcium carbonate ground calcium carbonate (GCC) is made of limestone or marble. These stones are crushed in several stages and ground to the required fineness. In the grinding process, it needs several times of purification. Generally, impurities are separated by flotation and magnetic separation, and a large amount of waste is often selected. Ground calcium carbonate contains small irregular crushed stones and flakes. On the contrary, PCC precipitation will proce very fine calcium carbonate crystals. This crystal can be made into different shapes (right side of the figure). The particle size of PCC can vary greatly according to the average particle size. For grinding calcium carbonate, the change of particle size is determined by the grinding times, while the particle size of PCC is controlled in the precipitation process. The shape of PCC is different from the required aggregation degree. Obviously, the aggregated particles will have a larger surface area (in m2 / g) than solid particles of the same size. The finer the limestone is ground, the smaller its average particle size is and the larger its surface area is. PCC showed more flexibility. With the method of manufacturing aggregate crystal, it can proce pigment with large particle size and large surface area. For example, it is easy to proce pigments with an average particle size of 2 mm and a surface area of 10 m2 / g with PCC. It is impossible to proce ground calcium carbonate. Using PCC as paper filler, the best high-grade paper filler is triangular PCC, which gathers into chrysanthemum shape. This proct gives the paper high brightness and opacity, at the same time, make the paper loose and strong. PCC can improve the brightness and opacity of the paper by 2 points, which is e to better light scattering. The loose thickness of the paper is also increased by 5%. At the same time, the smoothness of the paper is improved. On the negative side, it must be pointed out that the strength of the paper is slightly reced. PCC also requires more sizing (ADK or ASA). The properties of paper can be changed by changing the average particle size and surface area of PCC. A PCC with an average particle size of 2 mm and a surface area of 10 m2 / g will make the paper more opaque, but rece the bulk thickness. The coarser PCC (higher average particle size) will make the loose thickness higher and the strength higher. In general, if the filling amount is large, it should be changed from triangular PCC to rhombohedral PCC. The partial triangle PCC was used in normal proction. In the factory test, 50% partial triangle PCC and 50% rhombic hexahedron PCC were mixed. The paper mill wants to get higher filling quantity without losing sizing degree and strength. The surface area of rhombic hexahedral PCC is 4 m2 / g, while that of triangular PPC is 7 m2 / g. with 50 / 50 Mixed filler, the filling amount can be increased from 11% to 16% without loss of sizing degree and strength. At the same time, the increase of opacity is e to the higher filling amount. The paper mill wants to keep the thickness of the paper. Therefore, when the filling amount is increased, the calendering pressure is reced, which can not rece the smoothness of the paper. The results show that these examples just prove that PCC has a lot of flexibility. Another advantage of using PCC is to rece the wear of the paper machine. It is a comparison between PCC and ground calcium carbonate on paper machine wear. Obviously, grinding calcium carbonate on the paper machine wear is much greater, and greatly shorten the service life of the paper machine mesh, woolen cloth, etc. PCC is used for paper coating. Many kinds of PCC pigments have been developed for paper coating. At least three forms can be utilized, and the average particle size of each form can vary in a considerable range. It can be coated with 100% calcium carbonate instead of porcelain clay. The glossiness of paper varies with the fineness of PCC pigment. The results of three different calendering levels are shown. A kind of fine-grained PCC coating (average particle size is 0.4 μ m), and the paper gloss is increased to 80 by heavy calendering, which is a high index if porcelain clay is not used. When the average particle size increases, the glossiness of the paper will graally decrease. For example, if you want to achieve a paper gloss of 70, there are two ways. One is the use of heavy calendering and a thicker PCC (average particle size is 0.6 μ m), the other is the use of fine-grained PCC and light calendering. Lighter calendering will make the paper have higher brightness and opacity and higher loose thickness. Soft calendering and ll coating can be carried out with coarse PPC. Compared with grinding calcium carbonate, the general PCC coating can make the paper have higher gloss, smoothness and make the ink solidify faster. The pigment is used as the surface coating of paper without ground wood pulp. 80% calcium carbonate and 20% porcelain clay were used. PPC makes the paper have higher brightness and glossiness, and the surface strength does not decrease significantly. In general, the shape of PCC will change the properties of coated paper slightly. Changing the distribution of PCC pigment particle size, italics can control the curing speed of ink, other parameters will also be affected. PCC processing workshop attached to paper mill will often be able to get a variety of procts. Close cooperation between paper mill and PCC plant will get the best solution to the problem. Paper mills will naturally benefit from new procts that are constantly being developed. This will enable the paper mill to meet any user requirements.