The particle size distribution of antimony ore has a significant impact on the reaction in the rotary furnace. From the perspective of reaction kinetics, fine-grained antimony ore has a large specific surface area and is more fully in contact with the reaction gas (such as oxygen) in the rotary furnace. At the same temperature and atmosphere, it can react with the reaction gas faster, significantly increasing the reaction rate. For example, in oxidative roasting, the antimony minerals in fine-grained antimony ore can quickly combine with oxygen to be converted into antimony trioxide, shortening the reaction time and improving production efficiency.

On the contrary, coarse-grained antimony ore has a small specific surface area and has fewer opportunities to contact with the reaction gas, and the reaction rate is significantly reduced. In the rotary furnace, coarse-grained ore takes longer to reach the same degree of reaction as fine-grained ore, which prolongs the material residence time, reduces the rotary furnace processing capacity, and may also lead to energy waste. Because in order to make the coarse-grained ore fully react, it is often necessary to increase the roasting temperature or extend the roasting time, increase fuel consumption, and contradict the advantage of low energy consumption of rotary furnace pyrometallurgy.

In addition, the uniformity of antimony ore particle size distribution is also crucial. If the particle size is uneven, the reaction in the rotary furnace will be uneven, the fine particles will react first, and the coarse particles will not react completely, which will reduce the metal recovery rate. Moreover, the uneven particle size distribution will also affect the airflow distribution and material movement state in the furnace, making the temperature field and atmosphere unevenly distributed, affecting the reaction and product quality. For example, local coarse particle accumulation will hinder the airflow, causing local hypoxia or abnormal temperature, increasing the impurity content of the product and reducing the purity. Therefore, in actual production, in order to give full play to the advantages of rotary furnace smelting, it is necessary to reasonably crush and screen the antimony ore, control the particle size distribution, ensure uniformity and suitability, so as to improve production efficiency, metal recovery rate and product quality.