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Smashing of titanium raw materials
First, the purpose of crushing
Beneficiated titanium iron ore, or titanium slag by high initial crushing, which are relatively coarse particle size, difficult to react directly with sulfuric acid, since the titanium with sulfuric acid acidolysis is liquid-solid reaction, the reaction is carried out at the surface of the slag The finer the particle size of the ore powder, the faster the reaction rate and the more complete the reaction. Therefore, the titanium ore must be ground before use to increase the reaction contact area and increase the acid hydrolysis rate.
Second, the requirements of crushing
The particle size requirement of the mill should be fine first, and the particle size should be controlled at about 200 mesh to make the reaction proceed smoothly and obtain a higher acid hydrolysis rate. However, the particle size requirement of the ore powder is often related to the concentration of sulfuric acid used. If the concentration of sulfuric acid is high, for example, 98% or more of fuming sulfuric acid, the particle size of the ore powder should not be too fine, otherwise the reaction is too fast and easy to occur. A pan accident. If the concentration of sulfuric acid is low, the particle size of the ore should be finer, otherwise the reaction will not be complete. If the sulfuric acid concentration is 92.5% to 96%, the controlled particle size should be 99% through a 325 mesh (45 m) sieve. If the acid solution pot volume is 90 m 3 , the particle size can be controlled at 80% through a 325 mesh screen or 99% through a 200 mesh screen. If acid-soluble titanium slag is used for acid hydrolysis, the particle size is smaller due to less heat generation. Increasing the acid concentration, prolonging the reaction cycle, and increasing the preheating temperature can reduce the particle size of the ore.
Another requirement for comminution is that the particle size distribution is narrow and uniform, so that the acid hydrolysis reaction begins and simultaneously at the same time on each particle. If the particle size is very large, the coarse particles will not be completely reacted and the total reaction has ended, which will increase the unreacted residue and lower the acid hydrolysis rate, while the fine particles will be prematurely reacted, which will reduce the stability of the titanium liquid and increase the occurrence. The possibility of early hydrolysis.
Third, the crushing equipment
Raymond mill
Raymond mill is a kind of balance wheel grinder. It relies on the gravity and centrifugal force of the balance wheel to produce extrusion and grinding action on the steel ring to achieve the purpose of crushing materials.
A 4R (four-Roller) 3216 Raymond mill is generally used. The operation of this Raymond mill is to send the titanium mine bucket elevator to the hopper, and then enter the mill from the blanking pipe, pass between the grinding roller and the grinding ring (steel ring), that is, it is ground. At this time, the Fan continuously blows air upward from the bottom of the self-grinding machine , and the fine powder that has been pulverized is carried by the air, enters the separator, and is then introduced into the cyclone to settle, and the coarse particles are returned to the machine by gravity. . The particle size of the finished product can be controlled by adjusting the amount of blown air pressure.
When the Raymond mill is operated, the main engine and the fan should be started first, and the feed can be fed after the rotation speed is normal. During the operation, the amount of feed should be controlled and adjusted. If the amount of feed is too small, it will cause empty grinding. If the feed amount is too large, the mill may be blocked. The current of the main motor can be observed to make a judgment. If the current is too small, it indicates that there is an empty grinding phenomenon. If the current is too large, it indicates that a blockage is formed. In addition, the wind pressure of the fan should be adjusted according to the particle size of the discharged powder. It is necessary to make the product size qualified, and to make the output as much as possible. Generally, the output per hour is 1.2 to 1.4 tons.
It has been reported that surfactants are added to the mill. After they are adsorbed, they can reduce the free energy of the solid surface and reduce the cohesive force between the mineral powders. At the same time, the surfactants migrate into the gaps of the ore or mineral powder. To the cracking effect, thereby greatly increasing the pulverization rate. For example, the addition of 0.05% oleic acid during pulverization not only increases the mill yield, but also increases the acid hydrolysis rate by 1% to 2%.
2. Ball mill
The pulverization of ilmenite in foreign countries often uses a ball mill. There is a horizontal cylinder, and the grinding medium placed in the cylinder is usually spherical, so it is called a ball mill. The diameter of the balls varies in size. Adding ore sand during grinding, starting the ball mill to rotate the cylinder, the friction between the ball and the ball causes the mineral powder to be finely ground, and the material can be discharged after a normal time, and the grinding ball is sieved and reused.
The material of the grinding ball as a medium is required to have a high hardness and is usually made of granite . In order to prevent the cylindrical body from being worn, the inner wall of the cylinder should be lined with the same material as the grinding ball. In the introduction of foreign milling equipment, there is a hot air wind ball mill with a diameter of 2.8m and a length of 5.4m. Its production capacity is 7 tons/hour, which is suitable for combination of drying and crushing of 10,000-ton manufacturers.