In the treatment of steel plant dust, the binder treatment method is primarily used to address issues such as the fine particle size of the dust, its loose and easily airborne nature, and difficulties in transportation and reuse. By adding a binder, the dust is "formed" (e.g., into pellets or briquettes) to facilitate subsequent recycling (e.g., returning to sintering or blast furnaces) or safe disposal. The core principle involves the binding action of the adhesive, which creates stable bonds between dust particles, ensuring the strength, water resistance, and high-temperature stability of the formed products to meet subsequent process requirements.
Using polymer materials as the main component, binding occurs through surface tension and intermolecular forces, offering good formability at room temperature and high strength at low temperatures. Dust is used for low-temperature forming (e.g., building materials) or scenarios requiring volatilization without residue at high temperatures (e.g., zinc extraction, steelmaking).
Dust, binder, and water (to adjust humidity) are added in proportion: the binder dosage is typically 1%-5% of the dust mass (inorganic binders require more water, e.g., cement needs 10%-15% water; organic binders require less water, e.g., resins need 3%-5% water).
Return to sintering process: Dust pellets are blended into sintering materials to avoid fine dust becoming airborne, and binders (e.g., lime, sodium silicate) can act as fluxing agents to improve sintering efficiency;
Blast furnace / converter reuse: High-iron dust briquettes are directly fed into furnaces to reduce iron loss, with organic binders decomposing at high temperatures without residue;
Zinc extraction process: Electric furnace dust briquettes are fed into rotary kilns to prevent fine dust loss with flue gas, improving zinc recovery (briquettes have better permeability and more thorough volatilization);
Environmentally friendly transportation: Formed products reduce dust emissions (by over 80%), complying with environmental transportation standards.
Mixing: Double-shaft mixers or kneaders are used to ensure uniform mixing of binder and dust (mixing time 5-10 minutes, ensuring material "forms a ball when squeezed and breaks apart with light pressure"). The core of the binder treatment method is to address the physical defects of dust (looseness, dustiness) through "forming," while also selecting appropriate binders based on dust composition and reuse scenarios to achieve resource utilization with "low cost, high efficiency, and no secondary pollution."