With the booming development of the home decoration industry and the continuous advancement of old residential area renovation, the amount of renovation waste generated in China each year has exceeded 100 million tons. This type of waste has an extremely complex composition, mixed with wood, plastic, cloth, composite materials, masonry and cement blocks, as well as hidden metal debris such as nails and iron wires, making it much more difficult to dispose of than traditional waste. For a long time, the “landfill + open-air stacking” model has not only occupied a large amount of land resources, but also easily led to soil heavy metal pollution and water leakage pollution. At the same time, recyclable resources have been wasted, becoming a “persistent problem” in urban environmental governance. So how to dispose of construction waste efficiently?

A new type of renovation waste treatment production line integrating “crushing, separation, recycling, and energization” has completely changed this situation. With the core goals of “harmlessness, reduction, and resource utilization”, this production line realizes efficient treatment and value conversion of renovation waste through four key links.

The first step is grab feeding and double-shaft coarse crushing. Renovation waste is transported to the double-shaft coarse crusher through an intelligent grab. Equipped with high-strength wear-resistant crushing teeth and a double-shaft reverse linkage design, it can uniformly crush the “hard and soft mixed” waste into 10-30 cm block materials, avoiding blockage of subsequent equipment and breaking the “physical adhesion” of different components, laying the foundation for the next separation step.

The second step is air separation. The crushed mixed materials then enter the air separation equipment. Using the “aerodynamic principle”, the equipment generates a stable air flow through an adjustable speed fan to achieve separation according to the density difference of different substances: heavy materials such as masonry, cement blocks, and ceramic fragments, which are affected by gravity and fall directly. After collection, they can be further screened and cleaned to make recycled aggregates, which are used for road base paving, unburned brick production, etc.; light combustible materials such as wood, plastic, cloth, foam, and paper, which are less dense, are carried by the air flow into subsequent channels and become the core raw materials for preparing SRF fuel. The separation purity can reach more than 95%, avoiding heavy materials from mixing into combustibles and affecting the quality of subsequent fuel, while realizing “gradient utilization of resources”.

The third step is magnetic separation and recycling. Light combustible materials after separation often contain hidden metal impurities such as nails, iron wires, and aluminum alloy scraps. If these impurities enter the subsequent process, they will not only damage the equipment but also affect the purity of SRF fuel. Therefore, light materials first enter the strong magnetic separation equipment. Through a high-gradient magnetic field, the equipment can efficiently adsorb all iron-containing metals (with a recovery rate of over 98%), and non-ferrous metals (such as aluminum and copper) can be further recovered through subsequent eddy current separation equipment. The collected metals are packed and compressed, then directly sent to smelters for recycling, becoming raw materials for manufacturing new metal products. In terms of economic value, based on 3-5 kg of metal per ton of renovation waste, a production line with a daily disposal capacity of 100 tons can recover 10-18 tons of metal annually, creating considerable additional benefits.

The fourth step is fine crushing and screening. After removing metal impurities, the pure light combustible materials enter the fine crusher. The equipment adopts an “integrated hammer crushing and screening” design, further crushing the materials into 3-5 mm particles, and removing fine dust through a vibrating screen, finally obtaining high-calorific-value solid recovered fuel (SRF). SRF fuel has significant core advantages: stable calorific value, which can reach 3000-5000 kcal/kg depending on the composition of light materials (proportion of plastic and wood), close to medium-quality thermal coal; environmentally friendly combustion, with low sulfur and chlorine content, and pollutant emissions during combustion far lower than traditional coal-fired,wide application, which can be directly used in cement kiln co-processing, thermal power plants, industrial boilers and other scenarios, replacing fossil fuels such as coal and natural gas, and reducing enterprise energy costs.

The new technology has significant environmental, resource, and economic benefits. In terms of environmental benefits, under the traditional landfill method, plastics and coatings in renovation waste will slowly release toxic substances, seeping into soil and groundwater; open-air stacking is prone to dust and odors. The new production line effectively controls dust and harmful gas emissions through fully enclosed treatment (feeding, crushing, and separation are all carried out in a closed workshop); at the same time, more than 90% of the waste is converted into recycled aggregates or SRF fuel, greatly reducing the amount of landfill and fundamentally solving the pollution problem of renovation waste. In terms of resource benefits, “turning waste into treasure” alleviates resource shortages. China consumes a large amount of sand and gravel aggregates for the construction industry every year, and masonry and cement blocks in renovation waste can directly replace natural sand and gravel after treatment; metal recycling reduces reliance on mineral resources; SRF fuel replaces part of fossil energy, helping to achieve the “dual carbon” goals. Taking a production line with a daily disposal capacity of 100 tons as an example, it can recover about 20,000 tons of recycled aggregates, 15 tons of metals, and about 12,000 tons of SRF fuel annually, which is equivalent to saving 20,000 cubic meters of natural sand and gravel and reducing coal consumption by 8,000 tons. In terms of economic benefits, in the past, the disposal of renovation waste mostly relied on government subsidies, and it was difficult for enterprises to make profits. The new production line realizes a closed revenue loop through “resource recycling + product sales”: recycled aggregates can be sold to building material factories and municipal engineering units; recovered metals are directly sold to smelting enterprises; SRF fuel is favored by cement kilns, power plants and other enterprises due to its high calorific value and lower price than coal-fired. It is estimated that a fully equipped production line can recover the initial equipment investment within 1-2 years under normal operation, with stable long-term benefits.

This new type of production line can be flexibly configured according to the disposal capacity and is suitable for various scenarios: urban-level waste treatment centers with a daily disposal capacity of 200-300 tons, coping with centrally generated renovation waste in the region; building material markets/home decoration parks with a daily disposal capacity of 50-100 tons, handling merchant decoration and waste; old residential area renovation projects, temporarily equipped with small production lines (daily disposal capacity of 30-50 tons) to achieve “on-site treatment and on-site utilization”. In addition, SRF alternative fuel is convenient for transportation and storage. It can be compressed into blocks or granules with a density of 1.2-1.5 tons per cubic meter, small in volume, not easy to scatter, and low in transportation cost; storage only requires a dry and ventilated warehouse to avoid moisture, without special protective measures. Moreover, the production line is highly automated, equipped with a PLC control system, and only 3-5 staff members are needed to complete the operation (grab operator, central controller, inspector). The equipment has a fault warning function, is easy to operate, and staff can work after 1-2 weeks of training.

The “harmless and resource-based” disposal of renovation waste is an important part of the construction of “zero-waste cities” and an inevitable trend of urban green development. Through the whole-process innovation of “crushing – separation – recycling – fuel production”, the new renovation waste treatment production line not only solves the industry pain points of complex composition and difficult disposal of renovation waste but also builds a circular system of “waste – resources – energy”, providing a replicable and promotable solution for the resource utilization of construction waste.

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