In the operation of zinc oxide rotary kiln, coke powder is generally used as fuel for volatile leaching residue and oxide ore, which can also play a recovery role. Under normal conditions, the temperature in the zinc oxide rotary kiln mainly depends on the extinguishing of zinc vapor from coke powder. As long as the furnace temperature is raised and the heat is insufficient, the auxiliary fuel such as heavy oil will be selected to extinguish.

In practice, if the volatile matter in the coke powder is too high, it will be very unfavorable for the elongation of the reaction zone of the zinc oxide rotary kiln. Therefore, the ash content of the coke powder should not be too high. At the same time, the fixed carbon content in the coke powder is generally maintained at 65-75%, the volatile content is between 4-7%, and the ash content is 20-25%. From the operation of zinc oxide rotary kiln from time to time, we also know that the particle size of coke powder has a great impact on the operation of the kiln, including:

1. The results show that the zinc content in the slag is as high as 2.5%;

2. When the particle size is relatively fine, the air permeability of the charge in the zinc oxide rotary kiln is poor, which is not conducive to turnover. At this time, the zinc content of slag is as high as 2.18%;

3. When the particle size of coke powder is suitable, 30% of the coke powder is less than 5mm, and more than 50% of the coke powder with the particle size of 5-10 mm, and 1.5% of the slag with the particle size greater than 15 mm contains 1.5% zinc.

After the above analysis, we can know more carefully that the zinc concentration of slag generated by coke powder calcined in zinc oxide rotary kiln will be different due to the different particle size. Therefore, it is more convenient for our later zinc oxide rotary kiln calcination operation and practice.