From Ancient Waste Paper to Modern Environmentalism: Why Recycling Remains an Eternal Challenge?
Recycling Wisdom Hidden in History
As early as the Song Dynasty, China developed a mature waste paper recycling system. During the Northern Song period, scholars and literati repurposed discarded book pages into pulp for papermaking. The “recycling paper method” documented in The Book of Crafts involved reusing old documents and ledgers. By the Ming and Qing dynasties, the Jiangnan region had developed a complete waste recycling industry chain. Merchants roamed streets and alleys collecting rags and scrap paper, processing them into recycled textiles and paper. This millennia-spanning cyclical wisdom resonates with modern environmental principles, reflecting the Chinese nation’s enduring pursuit of “making full use of resources.”
The Essence of Recycling: The Three-Step Method That Never Changes
Regardless of technological evolution, recycling consistently follows three core steps: first, collecting and separating recyclables from waste; second, converting them into raw materials through specific processes; and finally, processing them into new products. Based on the “degree of transformation,” this process gives rise to three core forms: Primary, Secondary, and Tertiary Recycling.
Primary recycling refers to a circular model that extends an item’s original purpose without altering its form or core functionality. Simply put, it means “letting usable items find a new owner or context to continue performing their original function.” This approach requires no complex processes yet maximizes the retention of an item’s original value.
Clothing Revival: Mending worn cuffs or hems saves money and reduces waste compared to buying new clothes;
Community Swaps: Participate in neighborhood clothing or book exchanges to give unused items a “new purpose”;
Reuse Containers: Use supermarket egg cartons to collect fresh eggs from farms, reducing single-use packaging waste;
Charity Donation Chain: Donate 80% new furniture and appliances to thrift stores, supporting those in need;
Corporate Sustainable Design: Create “Built to Last” products designed for primary recycling from the outset.
Also known as “Upcycling,” secondary recycling is a creative and thoughtful circular approach that emphasizes repurposing items without altering their chemical composition. This model transcends traditional industrial assembly line constraints. Without complex machinery, ordinary individuals can breathe new life into seemingly useless waste with just scissors, twine, and paint. For instance: glass bottles painted with designs become unique vases; old sweaters unraveled into yarn are knitted into cozy coasters. Secondary recycling not only injects fresh energy into environmental conservation but also builds a creative bridge for public participation in eco-actions. It allows everyone to experience the joy of “turning trash into treasure” through hands-on transformation, driving the practice of green lifestyles with small yet meaningful efforts.
Shred old clothes into cleaning rags to replace non-recyclable paper towels;
Use pizza boxes (unrecyclable due to grease) as winter insulation mats in gardens;
Repurpose washed soup cans into pencil holders, candle holders, or mini planters.
Tires to Rubber Granules: In resource regeneration, waste tire processing exemplifies circular economy principles. Through precision physical treatments like shredding and grinding, end-of-life tires—nearly a meter in diameter—are transformed into 2-4 mm crumb rubber particles. These black granules combine elasticity and abrasion resistance, finding widespread use in synthetic running track surfacing, eco-friendly paving tile production, and even as asphalt modifiers to extend road lifespan. Estimates indicate each scrap tire yields approximately 30 kilograms of rubber granules, with over one billion discarded tires globally achieving this form of “rebirth” annually.
Cardboard Nurtures New Growth: Upcycling discarded corrugated cardboard boxes creates naturally biodegradable seedling containers. First, boxes are cut into standardized seedling trays with drainage holes at the base to ensure root respiration. After filling with sterile nutrient soil and sowing seeds, the trays can be directly buried in soil once seedlings develop 2-3 true leaves. This integrated “planting container + fertilizer” approach eliminates the white pollution from plastic seedling pots while enriching soil with organic matter, enabling each recycled cardboard sheet to undergo a green transformation from ‘paper’ to “plant.”
Glass Pre-processing: The HVST glass crusher employs a unique dual-shaft rotating design to instantly pulverize hard materials like waste glass bottles and window panes into uniform 5-10 mm particles. This pre-treatment technology effectively removes surface coatings and impurities while reducing energy consumption in subsequent sorting processes. The pre-processed glass particles can be further purified through magnetic separation, flotation, and other processes. This lays the foundation for secondary recycling into construction aggregates, glass fiber products, or remelted recycled glass, achieving a closed-loop utilization from “window to window.”
Secondary recycling process: First, cleaning removes surface dirt, impurities, and residual chemicals; then, crushing breaks materials into small pieces or fragments for easier handling; finally, pelletizing transforms crushed plastics into uniform granules. These granules serve as raw material for new plastic products, re-entering the plastic manufacturing cycle.
Secondary recycling process: First, pulping involves soaking and agitating paper/cardboard to break it down into a fibrous suspension. Impurities like ink, contaminants, and grit are then removed through de-inking and purification. After screening and bleaching, the fibers are reprocessed into paper suitable for printing, writing, packaging, and other applications.
Secondary recycling steps: First, waste glass is sorted by color and material. It is then crushed into fine particles. Finally, the glass particles are remelted into liquid form at high temperatures and shaped into new glass products like bottles, tableware, and architectural glass.
Secondary recycling process: Collected scrap metals are first smelted at high temperatures to liquefy them. Impurities, non-metallic components, and other alloy elements are then removed through purification processes to restore the metal’s purity and properties. Purified metals can be used to manufacture new metal products like automotive parts, mechanical components, and electronic casings.
Secondary recycling methods:
Physical disassembly: Mechanically dismantling used textiles into fibers, yarns, or fabric fragments. These raw materials can be used to produce recycled textiles like regenerated cotton batting and recycled yarn.
Chemical processing: Treating waste textiles with chemical agents to break down fiber structures, converting them into regenerated fibers suitable for re-spinning into new textiles.
Secondary Recycling Technologies: E-waste contains various precious metals (e.g., gold, silver, platinum) and rare metals (e.g., indium, gallium), requiring sophisticated techniques for recovery. Processes like chemical dissolution, electrolysis, and pyrometallurgy separate metals from e-waste, enabling efficient resource utilization while reducing reliance on virgin metal resources.
Secondary Recycling Methods:
Mechanical Shredding: Waste tires are mechanically shredded using specialized equipment into rubber powder of varying particle sizes. This powder can be used for laying rubber running tracks due to its excellent elasticity and wear resistance, or for producing rubber tiles, rubber product fillers, etc.
Pyrolysis: Under high-temperature, oxygen-free or oxygen-deficient conditions, tires are decomposed into fuel oil, carbon black, and steel wires. Fuel oil serves as industrial fuel; carbon black is used in rubber products, inks, and coatings; steel wires are recycled for reuse. This process reduces solid waste accumulation while generating new economic value.
When items completely lose their utility value, tertiary recycling takes over. This refers to an industrial-scale circular model that uses mechanical or chemical means to break down items into their original raw materials. Simply put, it means “disassembling items back into ‘parts’ to create new things.”
Mechanical Recycling: As the most widely applied recycling method, mechanical recycling relies primarily on physical processing. Utilizing diverse specialized machinery, it achieves material circulation through steps like shredding, washing, drying, and melt granulation. In practice, the **shredding** stage is often the critical first step, with different types of recycling equipment serving distinct functions:
Tire Recycling Machines: Designed specifically for end-of-life tires, these units feature dual-shaft shredders that use interlocking rotating blades to cut tires into large fragments. A wire separator then separates rubber from steel wires. The resulting rubber granules can be used for rubber tiles or sports surface materials, while the steel wires enter the metal recycling stream.
Metal Recycling Machines: When processing metal scrap, shears typically cut large metal components into manageable sizes, followed by further crushing with a crusher. For non-ferrous metals like aluminum and copper, eddy current separators are employed. These devices generate eddy currents through alternating magnetic fields, creating repulsive forces that separate metals from non-metallic impurities. For instance, discarded beverage cans undergo crushing, sorting, and smelting to be reprocessed into aluminum ingots for new aluminum products.
General-purpose plastic recycling machinery: Common PET plastic bottle recycling involves crushing bottles into fragments, removing labels and grease through washing equipment, drying the material, and feeding it into an extruder. Under high temperature and pressure, the plastic fragments are melted and extruded, then cut into uniform recycled plastic pellets by a pelletizer. These pellets can be used to produce new beverage bottles, fiber fabrics, or building materials.
Due to mature technology and controllable costs, mechanical recycling accounts for over 60% of the global plastic recycling market. However, it is limited by material property degradation and is typically only suitable for recycling homogeneous materials, making it difficult to process complex composite materials.
Energy Recovery: This method incinerates waste plastics, rubber, and other polymer materials to release thermal energy, which is then converted into electricity or steam. While energy recovery effectively reduces landfill volumes and provides clean energy, its emissions of pollutants like dioxins and heavy metals remain highly controversial. With advancing global carbon neutrality goals and stricter environmental regulations, energy recovery’s share in developed nations has declined annually. It is now primarily used for treating non-recyclable mixed waste or medical waste, requiring advanced flue gas purification systems to mitigate environmental impacts.
Chemical Recycling: Utilizing chemical reactions like pyrolysis, hydrolysis, and alcoholysis, chemical recycling breaks down polymeric materials into their original monomers or basic chemicals, achieving “molecular-level regeneration.” Taking polyester fiber (PET) as an example, alcoholysis can convert discarded clothing or beverage bottles into dimethyl terephthalate (DMT) and ethylene glycol. These can then be repolymerized to produce new products with properties comparable to virgin materials. This technology overcomes the limitations of mechanical recycling by processing mixed-material waste. The resulting regenerated products exhibit high purity and stable performance, positioning it as a key technology for achieving a closed-loop plastic economy. However, it currently faces industrialization challenges including complex processes and relatively high costs.
Tires’ core function is to bear vehicle weight. As the sole component connecting automobiles to the road surface, they must withstand complex loads including vehicle weight, driving force, braking force, and lateral forces. Continuous friction with the ground during use gradually wears down tread patterns. Once worn to the legal safety indicator line (typically 1.6 mm), tires lose their original utility. Composed primarily of synthetic rubber, steel cord, and fabric composites, tires exhibit exceptionally high chemical stability. This makes them nearly impossible to recycle through primary recycling cycles—simple physical processing to restore them to their original material state—in natural environments. However, they are perfectly suited for a combination of secondary and tertiary recycling: Secondary recycling involves shredding waste tires into rubber granules or powder for use in producing elastic materials like rubber tiles and running tracks. Tertiary recycling employs pyrolysis technology to decompose rubber into fuel oil, carbon black, and combustible gases, enabling deep resource recycling.
Secondary recycling of waste tires represents an ingenious journey of material rebirth. The process begins with mechanical pretreatment: Waste tires exceeding 1 meter in diameter are conveyed via a belt into a hydraulic shear, where they are precisely cut into manageable chunks. They then enter a twin-shaft shredder, where two sets of high-speed, interlocking blades reduce them to 2-5 cm rubber fragments. These preliminary fragments undergo magnetic separation to remove steel cord, followed by drum screening to eliminate impurities, ensuring raw material purity.
The rubber fragments then undergo fine grinding. In a low-temperature grinder, liquid nitrogen cooling rapidly lowers the temperature to -100°C, causing the rubber to enter a glassy, brittle state. Combined with the high-frequency vibration of a turbine grinder, this process ultimately produces fine crumb rubber with a particle size of 0.2-4 millimeters. This process maximizes the retention of rubber’s elastomer properties. Dynamic mechanical analysis confirms its tensile strength reaches 60%-70% of virgin rubber.
In application expansion, this crumb rubber serves as an ideal base material for anti-slip solutions due to its superior cushioning and weather resistance: Anti-slip mats formed by hot-pressing crumb rubber and eco-resin in a 7:3 ratio achieve a friction coefficient of 0.8 in wet conditions—far exceeding national standards. Soundproofing panels incorporating 30% rubber powder utilize impedance compounding principles to enhance noise reduction by 15dB across the 125-4000Hz frequency range, finding widespread application in rail transit sound barriers. This closed-loop model—“from tire to new material”—not only elevates resource utilization to over 95% but also significantly reduces emissions by 3.2 tons of carbon dioxide equivalent per ton of new material produced.
In the rubber industry, recycling aged tires represents a complex and critical process. When expanding this section, first highlight the challenges posed by tire aging, then detail the principles and workflow of chemical recycling technology, concluding with an emphasis on its closed-loop value to enhance both technical rigor and readability.
Severely aged tires suffer significantly degraded physical properties, losing their fundamental function as load-bearing components for vehicles. Their indiscriminate disposal causes severe environmental pollution and resource waste. Chemical recycling technology emerges as the breakthrough solution to this challenge. This process employs high-temperature pyrolysis and solvent extraction to break the cross-linked macromolecular chains within tires, decomposing them into polymer monomers. After purification and refinement, these monomers can be reintroduced as raw materials into production. Through polymerization reactions, they synthesize new rubber products with superior performance, achieving a true closed-loop “raw material rebirth” from “end-of-life tires” to “new rubber.” This process not only effectively resolves the environmental issue of tire accumulation but also paves a sustainable path for the rubber industry, revitalizing resources through circulation.
Reducing landfill pressure: According to the World Bank, over 2 billion tons of municipal solid waste are generated globally each year, with many landfills nearing capacity. Recycling effectively extends their operational lifespan.
Pollution Reduction: Curtails plastic entering oceans (currently hosting 5.25 trillion plastic items), safeguarding 1.1 million seabirds and animals killed annually by plastic debris;
Greenhouse Gas Mitigation: Lowers methane emissions from landfills and reduces carbon emissions from raw material extraction.
Recycling 1 ton of paper saves 17 trees; recycling aluminum saves 95% of the energy required for mining; recycling plastic reduces crude oil consumption. Behind these figures lies direct protection for scarce resources like forests and minerals.
Corporate Cost Optimization: Processing recycled waste costs 6 times less than regular waste disposal;
Production Cost Reduction: Manufacturing products with recycled materials saves 30%-50% compared to using virgin materials.
Individuals: From “Small Gestures” to “Systematic Action”
Primary Recycling: Sort unused items monthly, prioritizing donation or exchange;
Secondary Recycling: Explore Upcycle That platform to learn upcycling techniques;
Tertiary Recycling: Use Recycle Nation to verify local recycling rules and avoid wish-cycling.
Implement HVST tire recycling machines. Utilize low-temperature pyrolysis technology to decompose waste tires into steel wire, carbon black, and fuel oil. This equipment processes 3-5 tons of tires per hour. Pair with industrial shredders for pre-crushing tire carcasses, breaking intact tires into 5-10cm fragments to enhance subsequent processing efficiency.
Deploy dual-shaft industrial shredders for precision processing of electronic waste. Interlocking blade assemblies reduce mixed materials like circuit boards and plastic casings to particles under 20mm. Combined with eddy current separators, this achieves efficient metal-nonmetal separation while expanding secondary recycling services for specialized e-waste such as lithium batteries and displays.
Design packaging suitable for secondary recycling, such as adaptable cardboard boxes and cans.
Recycling is pivotal to building material cycles and advancing the circular economy. During revisions, remove references to Northern Song Dynasty history and employ more direct, compelling language to urge attention to recycling at all levels, emphasizing its significance for resource sustainability and economic development.
Every seemingly useless item holds potential as a valuable resource. Primary recycling stems from our reverence for materials—mending old items, reusing them, and extending their lifespans through small actions. Secondary recycling showcases creative transformation, turning discarded plastic bottles into stylish home goods and breathing new life into “trash.” Tertiary recycling relies on cutting-edge technologies like bio-enzymatic hydrolysis and high-temperature gasification to break down complex mixtures into reusable basic elements. These three interconnected dimensions—from individual conservation awareness to design-driven innovation and technological breakthroughs—collectively power the steady operation of modern circular economies. Let us take action, value every recycling step, blur the lines between resources and waste, and contribute to building a sustainable, flowing material cycle!
