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Solution to increase the amount of slag spit in cement mill vertical mill

Date:2019-10-29 13:50     writer:cement editor     Views:

Vertical mill because of its small area, low power consumption, steel consumption, low noise, and set drying, grinding, powder in one, has the advantages of compact structure, easy to operate, more and more people pay attention to and use.After the use of the vertical mill for a period of time, the amount of slag spit increases, which results in the decrease of the output of the vertical mill table, increases the labor intensity of workers and the corresponding power consumption, and increases the production cost.Solution to increase the amount of slag spit in cement mill vertical mill

vertical mill

1. Reasons for slag spitting of vertical mill


1.1 equipment reasons

(1) wear of the nozzle ring and damage of the upper cover plate of the nozzle ring result in the inner wind speed of the vertical mill not reaching the designed wind speed, and the material cannot be lifted in time, resulting in spoiling.

(2) the grinding disc ring of the vertical mill is severely worn, the gap increases, and the air leakage is serious, resulting in slag spitting.

(3) the guide cone is severely worn and cannot effectively guide the logistics and airflow.

(4) the grinding roller skin and the lining plate of the grinding disc wear seriously, resulting in a decrease in the grinding pressure and a poor grinding effect, resulting in an increase in the circulation load of the vertical mill, resulting in slag spitting.


1.2 material reasons

(1) the particle size of the material entering the vertical mill is larger than the maximum particle size allowed by the feeding port, and the proportion of large pieces of material is large, which increases the circulating load of the vertical mill, causes the instability of the material layer inside the membrane, and causes the increase of slag spitting.

(2) material segregation.Because of the material itself and the feeding time is not timely cause into the grinding block material concentration, so that the cycle load increases, resulting in slag spit.

(3) poor grinding property of materials.Improper clinker ratio and more difficult to grind components increase the circulation load in the vertical mill, resulting in slag spit.

(4) influence of fly ash.Some cement factory chooses to replace clay batching with fly ash, because wet season fly ash moisture is big, did not dry namely with limestone in homogenization factory batching.When the vertical mill is in operation, the fly ash is bonded to the feeding rambles and the three valve plates entering the mill. The more the fly ash is hanging, the more it falls into the mill suddenly to a certain extent, which makes the internal load of the vertical mill increase suddenly and slag emiting increases sharply.

vertical mill

1.3 system air leakage and insufficient air volume

(1) three valve plate into the mill is not flexible, usually open or due to the material moisture, after the valve plate is removed, the system air leakage is serious, resulting in slag spit.

(2) due to material deposition in the hot air pipe of the vertical mill, the flow of gas into the mill is less, and the air volume is insufficient, resulting in slag spitting.


2. Measures to reduce slag spitting in vertical mill


2.1 reduce slag spitting equipment of vertical mill

Regularly repair the welding nozzle ring and grinding disc ring, repair the damaged cover plate on the nozzle ring, and timely replace the guide cone, grinding roller skin and grinding disc lining plate.

vertical mill

2.2 reduction of slag spitting materials in vertical mill

(1) reduce the particle size of grinding materials (adjust the discharge of upstream crushing equipment).Increase the granularity of production management, timely feeding, reduce the segregation degree of materials, and keep the material level in the mixed bin above two-thirds.

(2) reduce the amount of materials with poor abrasion property.

(3) reduce water content of grinding materials.In the heap shed air drying, turning, at the bottom of the three valve into the mill add a preheating air pipe, hot air from the into the mill hot air pipe supply, so as to reduce the adhesion of wet materials in the three valve, conducive to the vertical mill material layer stability, reduce slag spit.


2.3 system air volume

Restore the three-way valve, and clean the accumulated material into the hot air pipe regularly.

Slag ejection of vertical mill is inevitable in normal production.In the actual production, if the phenomenon of slag spitting is encountered, the cause should be timely found, and the countermeasures should be found to restore production in time to ensure production benefits.

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