Drying and pulverization of ilmenite

First, dry

Bulk mines are generally used abroad, even in the open air, so they must be dried before they can be used. Iron ore of titanium, titanium white powder plant used is generally 30 to 40 kg / woven lined with plastic film of the bag, in the absence of moisture, generally does not require drying, but using mine, factory pre-mixed acid process, the most Use it after drying.

The drying of ilmenite is generally carried out in a wind sweeping mill. The wind sweeping mill belongs to a horizontal ball mill . After the ilmenite is ground in steel balls of different diameters, the hot air from the hot blast stove transports the ore powder to the harvest. Inside the feeder.

Second, the powder

In order to make the reaction of ilmenite with sulfuric acid as complete as possible, it is necessary to increase its reaction contact surface, because the speed of the general chemical reaction is proportional to its surface area, which can accelerate the effective collision rate between the two molecules, and additionally pulverize. There are many gaps on the surface of the ilmenite, which can allow H ⁺ and SO ₄ ²⁺ ions to penetrate into the reaction, so it needs to be crushed before use.

China's ilmenite pulverization generally uses Raymond mill, also known as balance wheel mill or suspension roller mill, ring roller mill, etc. (below). Raymond mill has large production capacity, low energy consumption and good product fineness, but it has high noise and vibration.

There are 2~6 suspension rolls on the cross on the vertical axis of the mill (the 4 rolls of Raymond mill are used in most factories in China). In addition to the self-rotation, these suspension rolls revolve around the axis with the pendulum. When the shaft revolves, due to the centrifugal force, the suspension roller is rotated against the grinding ring on the inner wall, and the ilmenite to be pulverized is added by the electromagnetic vibrating feeder, and is crushed between the suspension roller and the grinding ring. The grading of the material is controlled by the rotation speed of the classifier impeller above the pulverization chamber. The pulverized material is carried by the air flow sent by the centrifugal fan. When the speed of the classifier impeller is fast, more fine particles are carried out, and the rotation speed is slow. The coarse particles are carried out more, and the thicker large pulls fall into the bottom of the crushing chamber due to the gravity, and are scooped up by the rotary blade, and then re-grinded between the grinding ring and the hanging roller and then carried out with the air flow. The fine ore powder carried by the air is collected and stored in the ore powder bucket by a cyclone separator and a pulse bag type dust collector for use.

The fineness index after pulverization of ilmenite varies with the different art and the size of the acid hydrolysis reactor. Generally, the small and medium-sized titanium dioxide factory controls the fineness of about 325 mesh, about 1% of the sieve, and the large acid with a volume of more than 90m ³ The reactor is decomposed, and the fineness control of the ore powder is relatively coarse, and generally controls 1% of the 200 mesh sieve or about 20% of the 325 mesh sieve.

The pulverization of ilmenite generally does not require the addition of pulverization aids. In the past, it has been reported that the addition of 0.05% oleic acid during pulverization of ilmenite can not only increase the yield of the pulverizer, but also increase the acid hydrolysis rate by 1% to 2%.