Needle coke is the main raw material for the production of ultra-high power graphite electrode and supporting joint in steel plant. In the graphite electrode production formula, the powder content accounts for a high proportion (30%~57%), and the powder fineness has a great impact on the product quality, so the control of powder fineness in the product production process is very important. As the graphite electrode grinding mill manufacturer, HLM graphite electrode vertical roller mill produced by HCMilling(Guilin Hongcheng) has been widely used in the initial breaking and grinding process of needle coke. Below is your experience in processing needle coke grinding with graphite electrode vertical roller mill.

The process flow of the graphite electrode vertical roller mill for processing needle coke grinding is as follows: the graphite electrode vertical roller mill is driven by the motor drive mechanism to rotate the grinding disc in the mill, two grinding rollers rotate around the grinding roller shaft under the friction between the grinding disc and the material, the material enters the center of the grinding disc through the air-locked star feeder in the feed bin, and the material moves around the grinding disc under the centrifugal force of the rotary grinding disc, and enters the roller table between the grinding roller and the grinding disc. Under the action of hydraulic system and pressure device, the grinding roller applies pressure to the materials in the roller table for grinding. The milled material continues to move towards the edge of the grinding plate, overflows from the retaining ring and is blown in by the main fan. The air flow in the air duct is blown up and separated by the classifier. The qualified powder is discharged from the outlet above the vertical roller mill with the air flow, and is collected by the dust collection equipment and enters the finished product silo through the conveying equipment; Under the action of the classifier blade, the unqualified coarse material falls onto the grinding track of the grinding plate and is ground again.

In the experience of grinding needle coke with graphite electrode vertical roller mill, we summarized the following problems and solutions for your reference:

1. The needle coke processed by the graphite electrode vertical roller mill grinds the product too fine: during the commissioning and production, the sample analysis shows that the fineness of the grinding powder is 80%~90%, and the corresponding parameters can not reduce the fineness of the grinding powder. The final analysis reason is that the strength of the raw material needle coke is low, the particle size of the material entering the graphite electrode vertical roller mill is too fine, and the pressure of the grinding roller after entering the graphite electrode vertical roller mill is too large, resulting in too fine grinding powder. Although the pressure of the grinding roller has been adjusted, the pressure of the energy accumulator corresponding to the grinding roller has been 5 MPa, resulting in the feedback pressure of the grinding roller has been fluctuating between 4.5 and 5 MPa, indicating that the excessive pressure of the grinding roller causes the fine grinding.

Solution: adjust the pressure of the mill roll to 3.5 MPa, and release the pressure of the accumulator to 3.5 MPa.

2. Excessive slag discharge from the slag discharge port of the graphite electrode grinding mill: during grinding, it was found that the slag discharge volume of the mill was too large, and the material discharged from the slag discharge port was about 2th, which seriously affected the capacity of the graphite electrode vertical roller mill.

Treatment measures: on the premise of ensuring the production capacity and powder fineness, increase the height of the baffle plate of the graphite electrode vertical roller mill; At the same time, the transparent glass shall be installed at the appropriate position of the mill access door to form an observation hole so that the thickness of the material layer in the material chamber can be accurately grasped during commissioning

3. The lubricating oil supply temperature of the main shaft reducer of the graphite electrode vertical roller mill is too high or too low: when the mill operates for more than 2 hours, the temperature of the lubricating oil station of the main shaft reducer starts to rise rapidly to the programmed alarm temperature. If it continues to operate, it will cause the mill protection shutdown and seriously affect the continuity of the mill operation.

Treatment measures: install an automatic temperature control valve on the cooling water pipe of the lubricating oil station, and automatically adjust the opening of the cooling water valve by collecting the oil supply temperature of the lubricating oil station to ensure that the lubricating oil temperature of the lubricating oil station is within the specified range.

4. The graphite electrode vertical roller mill has the advantages of large capacity, high grinding efficiency, convenient maintenance and low maintenance cost, and is suitable for large-scale production. At present, it is mainly used in the processing of ultra-fine powder in cement, electric power and metallurgical industries. However, it is rarely used in the carbon industry. Only HLM series graphite electrode vertical roller mill of HCMilling(Guilin Hongcheng) has experience in processing needle coke powder in China. In the process of large-scale production in the carbon industry, if you want to obtain qualified products, you must improve and grope through continuous debugging according to the strength and size of materials, as well as the performance of the graphite electrode grinding mill and the design of the grinding system, so as to grasp the relationship between the parameters of the graphite electrode vertical roller mill. When the graphite electrode vertical roller mill is in a stable working state, It is easier to control and grind qualified and stable products.

The HLM graphite electrode vertical roller mill produced by HCMilling(Guilin Hongcheng) has rich experience in processing needle coke powder. If you have purchase requirements for graphite electrode grinding mill, please contact us for equipment details.