Overview of Zinc Ore Smelting Process

The zinc ore smelting process is mainly divided into two categories: pyrometallurgy and hydrometallurgy, and the technological development is evolving towards high efficiency and environmental protection.

Pyrometallurgical process

This method is based on the principle of high-temperature reduction and is suitable for processing various types of zinc ore resources:

Modern vertical tank zinc refining technology: using carbonaceous reducing agent to reduce zinc pellets in a vertical shaft distillation tank, the temperature needs to be higher than the zinc boiling point (1179K), and the zinc vapor is treated by a splash condenser, with a recovery rate of 95% -97% and a direct zinc yield of over 96%. The energy consumption per ton of zinc is about 1.75 tons of standard coal;

 The core of this process includes three parts: pellet preparation, reduction distillation, and condensation. It once accounted for 11% of global zinc production, but was later replaced by wet process technology.

Rotary kiln zinc extraction process: based on the principle of high-temperature reduction volatilization, used for processing low-grade zinc ore or zinc containing smoke and dust;

 By controlling the kiln temperature (1100-1200 ℃), raw material ratio (C/ZnO=1:4-1:5), and rotation speed (0.5-1.5 r/min), the zinc recovery rate can reach over 92%, and the energy consumption per ton of zinc can be reduced to 3.2-3.5 GJ. The flue gas emissions meet national standards.

Wet metallurgical process

This method treats zinc ore through chemical leaching and precipitation, with high recovery rate and excellent environmental friendliness

Traditional wet zinc smelting involves steps such as sulfuric acid leaching, but there are issues with high energy consumption and waste residue;

 Zinc oxide, as an intermediate product, can be obtained in high-purity form through chemical precipitation method.