"Zinc Slag Alchemy": How a Rotary Kiln for Secondary Roasting of Zinc Oxide Turns Waste into Treasure?

With the rapid growth of industrial production and resource recycling, zinc suboxide rotary kiln has become a “green pearl” in the zinc smelting industry due to its efficient and environmentally friendly technological advantages. It not only transforms industrial waste into high-value-added products, but also promotes the sustainable development of the industry through a low-carbon process. Today, HENAN ZHENGZHOU MINING MACHINERY CO., LTD. introduced this equipment to explore its main technological capabilities and practical application.

I. Zinc Suboxide Rotary Kiln: “Resource Alchemy” at High Temperature

Zinc oxide secondary calcination rotary kiln is the main equipment for processing zinc-containing materials by high-temperature calcination. Its working principle is based on the physical and chemical properties of zinc compounds. In the high-temperature furnace environment (1100-1250 °C), zinc contained in zinc-containing slag (e.g. steel dust, zinc-lead slag, etc.) reacts with a reducing agent (e.g. coke) to form secondary zinc oxide and gaseous products. This process not only achieves effective zinc recovery, but also simultaneously recovers valuable metals such as lead and cadmium, truly realizing the principle of “drying and squeezing”.

Technical Features:

Selective reduction: Using the low boiling point of zinc (907 °C), it is preferentially evaporated in a reducing atmosphere and then oxidized to form secondary zinc oxide dust, achieving precise separation.

Waste heat utilization: A waste heat boiler is installed at the end of the furnace to recover the heat of high-temperature flue gas for power generation or heating, which can reduce energy consumption by more than 15%.

Intelligent control: Hydraulic locking wheels, infrared scanners and other devices are used to monitor the temperature of the calcining zone in real time, ensuring the stability of the process.

2. From waste slag to treasure: the “path to rebirth” of secondary zinc oxide

The technological process of the rotary kiln for secondary zinc oxide combines physical calcination and chemical reaction, forming a closed industrial chain:

Pre-treatment of raw materials: zinc-containing waste slag (such as steelmaking soot, iron slag and manganese slag) is mixed with coke in proportion to obtain granules of 8-15mm in size to improve reaction efficiency.

High-temperature calcination: the material goes through three stages: drying, medium-temperature reduction and high-temperature oxidation in the kiln. Zinc vapor combines with oxygen to form secondary zinc oxide, which enters the dust collection system along with flue gases.

Environmental purification: Flue gas meets emission standards after surface cooling, pulse dust removal, desulfurization and denitrification. The dust collection rate is over 95%. Slag is used for recycling after water quenching, ensuring zero pollution to the environment.

Application areas:

Metallurgy industry: Extraction of valuable metals from lead-zinc slag and hydrometallurgical zinc slag.

Environmental protection: Recycling hazardous industrial waste (such as zinc sludge, electronic waste) to reduce the burden on the environment.

New material industry: Production of rubber reinforcing additives, ceramic glazes, electronic components, etc.