1. Project Background In recent years, with the rapid development of China's electronics industry, the printed circuit board (PCB) industry, as the foundation of the electronics industry, has continued to grow at an annual rate of 14.4%. In 2006, China surpassed Japan to become the world's largest PCB production base in terms of output value. The annual output value of China's PCB industry reached 29 billion US dollars, mainly distributed in the "Yangtze River Delta" and "Pearl River Delta" regions. During the production process of PCBs, a large amount of etching waste liquid containing high concentrations of copper is generated. The main components of these etching waste liquids are copper salts, which also include other inorganic substances such as ammonia, hydrochloric acid, hydrogen peroxide, sulfuric acid, etc. These components, when combined together, have extremely high pollution indices and belong to hazardous liquid wastes. At the same time, the concentration of copper ions in the etching waste liquids exceeds several million times the standard, indicating huge potential for resource recovery. Currently, In our country, the average daily production of etching waste liquid exceeds 2000 tons per day, and it continues to grow at a rate of about 10% annually. Generally, for the production of 1 square meter of circuit board, 2 to 2.5 liters of etching liquid are consumed, and correspondingly, 2 to 2.5 liters of etching waste liquid are produced. The PCB industry consumes more than 100,000 tons of refined copper each year, while the copper content in etching waste liquid is over 50,000 tons. In the actual industrial production process of our country, the common practice for treating etching waste liquid is to store it in sealed tanks within each PCB manufacturing plant and then send it for treatment by external environmental protection units. Commonly used methods for waste liquid treatment include chemical precipitation, electrolysis, and extraction, which prepare the copper in the etching waste liquid into products such as copper sulfate, electrolytic copper plates, or copper oxide powder. The added value of these treatment methods' products is low, and their economic performance is poor. 2. Technological Advantages: Supercritical hydrothermal synthesis reactions refer to the process in a sealed high-pressure reactor where supercritical water is used as the reaction medium, causing metal salts to undergo hydrolysis and dehydration reactions in the hydrothermal medium. This leads to nucleation, growth, and ultimately the formation of nanocrystalline particles with a certain particle size and crystalline morphology. Since the reaction medium is supercritical water and the process occurs in a sealed high-pressure container, no other pollutants are introduced during the reaction, making it considered an environmentally friendly green nanotechnology preparation method. The use of supercritical hydrothermal synthesis for treating copper-containing wastewaters can achieve a Cu2+ conversion rate of over 99.8%, with the average particle size of the product reaching 10~20nm. Analysis shows that the product is entirely composed of Cu, with a purity of over 99.9%. Moreover, the treated wastewater can be completely recycled, achieving zero discharge of wastewaters. 3. Market Economy Analysis Taking the system for the supercritical hydrothermal synthesis of nanoscale copper from printed circuit board etching waste liquid with a treatment capacity of 10t/d as an example, if the Cu2+ concentration in the waste liquid is 120g/L, the equipment investment cost is about 10 million yuan, the operating cost for treating one ton of waste water is 3514 yuan/ton, and the revenue from treating one ton of waste water is approximately 360,000 yuan/ton. Based on this estimation, the entire project's investment can be recovered within three months, and in addition, a net profit of about 100 million yuan per year can be generated. Therefore, this technology has strong technical and economic advantages and broad market prospects. 4. Main Application Fields This technology is suitable for the harmless treatment of production waste water from printed circuit board factories and related fields of resource utilization. There are no geographical restrictions on the application of this technology. 5. Cooperation Conditions Requirements (1) Natural persons or corporate entities with the capacity to independently bear civil liability. (2) Conduct industrial demonstration and operation in a combination of industry, academia, and research, with cooperating enterprises providing funding and operational support. (3) Possess certain investment capabilities and risk awareness, as well as the ability to market and expand.