The direct method of calcining zinc oxide is the process of preparing zinc oxide from zinc-containing materials or metallic zinc. Zinc oxide is widely used in rubber, paint, porcelain enamel, ceramics, glass and medicine, agriculture, electronics and other departments. Zinc oxide production methods are divided into fire and wet methods. The fire method is to directly reduce the zinc-bearing material at a high temperature, and then re-oxidize the produced zinc vapor to obtain zinc oxide; or use a metal zinc as a raw material to volatilize and oxidize zinc oxide. The former is called direct method and the latter is called indirect method. The direct method uses zinc concentrate as raw material, removes lead, cadmium, sulfur and other impurities after high-temperature oxidation roasting, together with reduced coal and pressed into a group, and then high-temperature reduction in the furnace, volatile zinc vapor and gas in the furnace CO2 and the introduced air are directly oxidized to zinc oxide. China Hunan Hengyang Guotai Pigment Factory has been using fixed Wechsler furnace to produce zinc oxide directly since 1941. The process flow is shown in Figure 1. Wechsler Furnace is a rectangular furnace with an area of 10m2 in the hearth, daily treatment of 15 to 20t of mined ore, and daily production of zinc oxide (ZnO ≥ 99.5%) 4 to 7t. The direct recovery rate of zinc in the production process is 71%; the smelting recovery rate is 88%; the reduced coal unit consumption per ton of zinc oxide products is 1.6-2.1t, and the electricity consumption is 300-400kW•h. Directly produced zinc oxide is usually acicular or rod-like crystals, coarse particles. In addition to the quality of the product and the quality of the zinc concentrate, the product quality is also related to the quality of the reduced coal. The volatilized zinc vapor is directly contaminated by the reduced coal combustion product.