Flue ash is an inevitable industrial solid waste generated during steel production processes such as sintering and blast furnace smelting. This material has a complex composition, featuring high zinc content and concealed iron content ranging from 30% to 50%. Once a hot potato for steel enterprises, the zinc element in flue ash is prone to volatilization and nodulation during subsequent treatment, causing equipment blockages, frequent shutdowns, and increased operation and maintenance costs. Meanwhile, the valuable iron resources, encapsulated by zinc and other impurities, are difficult to recover efficiently and can only be disposed of at low prices or landfilled. This not only results in resource waste but also exposes enterprises to stringent environmental supervision pressures, trapping them in a triple predicament of difficult solid waste disposal, substantial resource loss, and high environmental risks.
Tailored to the characteristics of steel plant flue ash, the rotary kiln-based zinc removal and iron enrichment technology, which operates on the principle of high-temperature reduction, is rapidly emerging as a new favorite in the industry. By precisely controlling the kiln temperature (typically 1100–1300℃), atmosphere (reducing environment), and material residence time, zinc oxide in the flue ash is effectively reduced and volatilized, followed by the recovery of high-purity zinc oxide powder through dust collection systems. Iron, on the other hand, is enriched in the kiln slag in the form of metallic iron or magnetic iron oxide, which can be directly recycled back to the steelmaking process as high-quality iron feedstock. This innovative solution, custom-built for flue ash, overcomes the drawbacks of traditional disposal technologies such as incomplete zinc removal and low iron recovery efficiency. By precisely matching the physical and chemical properties of flue ash, it achieves dual breakthroughs in deep zinc removal and efficient iron resource enrichment, transforming the once environmental burden into a treasure trove of iron and zinc and creating new profit growth points for steel enterprises.
Three Exclusive Advantages to Address the Core Pain Points of Flue Ash Disposal

1. Precision Zinc Removal for Uninterrupted Equipment Operation

Targeting the occurrence forms of zinc in flue ash, this technology completely eliminates kiln nodulation and pipeline blockage caused by zinc vapor condensation, ensuring the continuous and stable operation of rotary kilns.

2. Customized Solutions for Maximum Adaptability

Fully considering the composition fluctuations of steel plant flue ash (e.g., variations in zinc and iron content) and differences in production capacity requirements, the scheme allows flexible adjustments to kiln temperature, material residence time, and separation process parameters. Whether for small steel mills with an annual flue ash treatment capacity of 50,000 tons or large steel enterprises handling over 200,000 tons annually, stable and high-efficiency operation can be achieved.

3. Green Compliance for Zero-Burden Disposal

The entire process adopts a closed-loop treatment system. Zinc slag produced during zinc removal can be legally recycled for zinc smelting, while tailings can be used for iron extraction, realizing full utilization of solid waste and zero emissions. This enables enterprises to easily pass environmental inspections and supports their efforts to achieve the dual carbon goals.
Against the backdrop of the steel industry’s trend toward cost reduction, efficiency improvement, and green transformation, the efficient utilization of flue ash—an untapped resource rich in iron and zinc—has become the key to enhancing enterprises’ core competitiveness. The rotary kiln’s exclusive zinc removal and iron enrichment technology not only helps you solve the flue ash disposal dilemma but also generates substantial returns through resource recovery, reducing production costs and avoiding environmental risks.
Zhengzhou Mining Machinery Co., Ltd. boasts over 10 years of experience in solid waste treatment technology for the steel industry. Our core team consists of experts in metallurgical engineering and kiln design, offering one-stop turnkey services covering flue ash composition testing, customized solution design, equipment installation and commissioning, as well as long-term operation and maintenance support. We ensure that our technology delivers immediate results upon implementation and maintains stable long-term operation.