At 4 a.m., the last street lamp in the city went out, while another beam of light shone from the Lvyuan Recycling Plant in the suburbs. It was a three-story circuit board recycling device, like a silent steel giant, slowly swallowing the used mobile phones, computers, and home appliance "hearts" brought in from all over the day. The conveyor belt started up, and the blade roller first tore apart the plastic shells. The magnetic separator, like a meticulous butler, sorted the iron screws and copper coils into different "rooms". Further ahead, the high-pressure electrostatic field quietly worked its magic, making the 0.1-millimeter-thick copper foil and glass fiber cloth instantly "separate". Standing in front of the observation window for the first time, I seemed to hear the electronic components shouting: "Please give us a second life!" 　　Circuit boards were once called "urban mines". Only 5 grams of gold were contained in a ton of ore, while 200 grams could be extracted from a ton of circuit boards, along with rare metals such as palladium and rhodium. 　　However, this "mine" also harbored deadly toxins: lead, cadmium, and brominated flame retardants could contaminate the soil if they leaked into it with acid-washing wastewater, leaving not a single blade of grass to grow. 　　Lvyuan's equipment solved the dilemma with a "fully dry method" - low-temperature crushing, negative pressure transportation, and nitrogen protection, locking the dust and odors in sealed pipes. At the end, activated carbon and bag filters were installed, with PM2.5 emission concentrations below 10 micrograms per cubic meter, cleaner than the kitchen fumes. 　　Engineer Zhou Zhenyu said, "We're not just dealing with waste, but performing dialysis for the Earth." 　　The most impressive was the "metal richness inspection device". 　　It was like a CT scanner, taking 300 X-ray images per second. AI algorithms could calculate the content of copper, tin, and gold within 0.2 seconds and direct 128 high-speed nozzles to blow different metal particles into corresponding bins. 　　In the past, manual sorting required workers to wear three layers of gloves and still get cut. Now, only two on-duty staff members are needed, wearing white gloves in the air-conditioned control room. 　　That day, I saw a 0.3-millimeter gold particle accurately captured and placed in a transparent sampling bottle, like a morning star illuminating the entire factory. 　　In the evening, a brand-new copper ingot slowly emerged from the equipment's output end, its surface reflecting the sunset. 　　Zhou Zhenyu handed it to me and said, "Yesterday, it was still on a used motherboard. Tomorrow, it might be in the coils of a wind turbine." 　　Suddenly, I realized that recycling isn't the end, but the starting point of the next surging electric current. 　　The circuit board recycling equipment tells the world with its steel arms: true civilization isn't about turning resources into waste, but making waste into resources again. 　　When the last ray of sunshine shone on the equipment's top, the metallic cold light and the warm color of the sky merged - it was the gentlest handshake between industry and nature, and the firmest promise of humanity to the future.