Figure 46 is a schematic diagram of the operation of the QSB type cyclone jet mill produced by Shanghai Chemical Machinery No. 3 Plant in China; this type of jet mill has been serialized. [next] The structure of PQF type cyclone jet mill produced by Sichuan Mianzhu Chemical Plant is similar to that of Shanghai Chemical Machinery No. 3 Plant; PQF jet mill has also been serialized. The operating system of the elliptical tubular jet mill is shown in Figure 48. C Convection Jet Mill The earliest and more typical device for convection jet mills is the Schneider decompression pulverization method. This pulverization method was developed by American FA Snyder in 1950, so it is called Schneider's method. The essence is that high-temperature steam is sprayed from the nozzle to the crushing chamber at a high speed. In the crushing chamber, the airflow is decompressed due to the sudden expansion of the volume; thus, the material is subjected to high-speed impact and frictional force, and the osmotic embrittlement and pressure of the water vapor are added. It is shattered by the effect. Figure 49 shows the working system of such a device. Such devices feed particle size 5-6 mm, and the pressure 0.49 to 4.9 MPa (5 to 50 kgf / cm 2), the valve opening speed of 15 microseconds (10-6 seconds), the gas flow velocity close to the speed of sound, the particle velocity Up to 100 m / s. Later, the only American Star (Lone Star) company for cement, ferrous metals, non-ferrous metal ore semi-industrial and industrial tests, get good results. The company has built (10 tons /) process sponge iron and dolomite (70 t / h) of the Act Schneider factory. [next] The former Soviet Union also conducted a large number of experimental studies on this jet mill. For example, a comparison test between a MCП-25 convection jet mill and a ф2.6×13 m cylindrical mill to treat a slag cement plant shows that the former has a grinding cost of 1.58 rubles per ton and the latter is 1.8 rubles per ton; the cement industry The average grinding cost is 1.6 rubles. The former Soviet Union has carried out serial production of convective jet mills, processing 100 tons of coal or iron ore per hour and treating 160 tons of cement. Drymix Mortar admixtures has wide range of products, including HPMC, MHEC, RDP, HPS, PVA. Drymix Mortar Admixtures,Calcium Formate,Lignocellulose,Potassium Formate Santo Chemical Limited , https://www.santchem.com
B Elliptical tube jet mill [next]
Figure 47 is a working principle diagram of the elliptical tube jet mill, the abrasive chamber is an elliptical pipe; the pipe diameter is generally 25-200 mm, the height is 1000-2500 mm; many nozzles are installed at the lower bend thereof, and the air flow is This entry creates a strong circulation. The material to be ground is sprayed from the side from the nozzle into the jet zone; the material in the jet zone is accelerated and collides. The movement speed of the internal and external streams in the pipeline is different, the coarse particles tend to the outer layer, and the fine particles tend to the inner layer, so that the fine particles are discharged through the discharge opening. [next]
Figure 50 is another convection jet mill in which compressed air (or superheated steam) is ejected through a nozzle of a spray pipe after it is preheated in the combustion chamber, so that the gas flow expands due to sudden decompression. The airflow moving at a speed of 100~200 m/s blows 5~3 mm of material in the feeding tube into the conical grinding chamber in a tangential direction, so that the mutual impact and grinding between the high-speed moving ore particles is utilized. The effect is to smash it.