Reduction: Through source control and efficient disposal, minimize the stockpiling of solid waste, reduce land occupation and environmental pressure, and lower ecological risks caused by surface accumulation from the source.
Harmless Treatment: Adopt scientific treatment technologies to eliminate hidden dangers such as spontaneous combustion and leakage of solid waste, ensure that the whole treatment process and final products comply with national environmental protection standards, and prevent secondary pollution.
Recycling Utilization: Tap the intrinsic value of solid waste, promote its transformation from "ecological burden" to "economic resource", realize classified and cascaded utilization, improve resource efficiency and economic benefits, and establish a circular economy model.
Compliance: Strictly abide by national and local laws, regulations and policies on solid waste treatment and environmental protection, ensure full-process compliant operation, and support enterprises in green transformation.
Pretreatment is a key link to improve the utilization efficiency of solid waste and reduce treatment costs. Its core goal is to remove impurities, adjust solid waste characteristics to meet the requirements of subsequent treatment and utilization. Following the principle of "classified pretreatment and targeted measures", it avoids mixed disposal of different types of solid waste that may impair utilization performance.
Crushing and Screening: Equipped with jaw crushers, impact crushers and other equipment, the ash residue is crushed to a suitable particle size (generally 5mm-50mm, determined by subsequent utilization scenarios). Vibrating screening equipment is adopted to separate ash residue of different particle sizes and remove bulk impurities such as waste iron, steel and stones, so as to improve the uniformity of materials.
Impurity Removal and Dust Reduction: Magnetic separation equipment is used to remove ferromagnetic impurities and reduce abrasion of follow-up equipment. Measures including bag dust collection and spray dust suppression are applied to control dust emission during pretreatment and meet environmental protection supervision standards.
Drying Treatment: When the moisture content of ash residue exceeds 15%, drum dryers, flash dryers and other drying devices are adopted to reduce the moisture content below 10%, preventing adverse impacts on subsequent combustion, forming and cementing reaction.
1) Pretreatment of Coal Gangue
Crushing and Screening: According to the calorific value and utilization direction, coal gangue is crushed into targeted particle sizes. High-calorific-value gangue is processed into particle sizes suitable for combustion, while low-calorific-value gangue is crushed to meet the particle size requirements for building materials production.
Sorting and Grading: Dense medium separation, jigging separation or photoelectric separation technologies are adopted to recover coal resources from carbon-rich coal gangue and increase heat value. Through grading and quality separation technologies including particle size screening, crushing dissociation and density separation, high-aluminum coal gangue is divided into raw materials for calcined kaolin, metakaolin and high-calorific gangue, laying a foundation for high-value utilization.
Desulfurization Treatment: For high-sulfur coal gangue, the MFD microbial catalytic oxidation technology is applied to oxidize organic sulfur and inorganic sulfur in coal under normal temperature and pressure, with a desulfurization rate of over 80%. It effectively inhibits spontaneous combustion and acid water generation to avoid secondary pollution.
2) Pretreatment of Fly Ash
Dust Collection and Storage: High-efficiency facilities such as electrostatic precipitators and baghouse dust collectors are used to collect fly ash, which is stored in sealed silos. Different types and grades of fly ash are stored separately to prevent mixing and dust pollution.
Sorting and Grading: Air classification and mechanical separation technologies are adopted to remove coarse particles and impurities. Fly ash is classified into Grade I and Grade II products to meet quality standards of various building materials and increase added value.
Activation Treatment: For low-activity fly ash, mechanical activation or chemical activation (with activator addition) is adopted to enhance cementitious activity, so as to adapt to the production demands of cement, concrete and other building materials.
