JX Nippon Mining & Metals Corporation conducts global business operations in the area of nonferrous metals, focusing primarily on copper and rare metals. These operations cover the entire range from resource development, smelting and refining, to the development and manufacture of advanced materials that are essential for the use of AI and IoT technologies in the society. The Group’s operations also include the recycling of end-of-life electronic equipment and other devices.
The recycling business recovers copper, precious metals and other valuable metals from end-of-life home appliances and electronic equipment, as well as from recycled materials such as metal scrap generated by factories. The environmental services business cooperates with our group companies to detoxify industrial waste and to recover valuable metals. The fundamental principle of both businesses is zero emissions, that is, the principle of not generating any secondary wastes. These businesses are contributing to the creation of a global resource-recycling society so that the environmental burden will not be left to future generations.
This paper reviews recycling technologies in Astec-irie Co., Ltd. Repellent substances and valuable metals, such as precious metals and rare metals, contained in waste electronics were separated and concentrated using superheated steam, an aqueous iron (III) chloride solution, and AI. The electronic components and substrates were separated by melting the solder with superheated steam, and the repellent substance in non-iron smelting was removed from them. The gold-plated parts contained in the electronic components were separated back into gold by dissolving the copper and nickel in the aqueous iron (III) chloride solution. The copper and nickel dissolved into the solution were separated and recovered respectively as solid components by adding iron powder. The useful metals were concentrated from the separated electronic components, which are sorted out using AI. As a result, valuable metals such as precious metals could be concentrated while reducing the concentration of repellents, thus making it possible to treat the removed repellents as useful substance.
Recently, the recycling of precious metals from scrap generated during manufacturing processes and from end-of-use products has encountered issues associated with environmental regulations. Furthermore, there is a continuous increase in the demand for precious-metal materials with better qualities. The initiatives undertaken by Matsuda Sangyo Co., Ltd. to overcome the abovementioned challenges are discussed in this paper. These initiatives include the development of high-quality sputtering target materials and the effective use of nitrogen-containing wastewater generated from recycling processes. Advanced recycling technologies for lithium-ion batteries are also introduced.
Spent automobile catalysts are the most important secondary resource for platinum group metals (PGMs), and their recycling is essential not only to ensure a steady supply of PGMs but also to preserve the natural environment. However, several factors limit the efficiency of PGM recovery in current recycling processes. Specifically, PGMs represent a small proportion of the entire catalyst and are difficult to dissolve in aqueous solutions for subsequent separation. In recent decades, multiple technologies have been developed to make the recycling of PGMs more efficient and environment-friendly. Herein, we introduce the typical industrial processes for recovering PGMs from spent catalysts as well as established and emerging trends in the technological development of PGM recycling. Furthermore, we review novel recycling techniques for converting PGMs in spent catalysts into more soluble states and/or physically concentrating PGMs from spent catalysts.
Highly effective refining of precious metals requires detailed knowledge of the chemical properties of their complexes in leaching solutions. Speciation studies on precious metal ions in solution have been performed for about a century. Early studies have mainly provided stability constants between precious metal ions and their ligands. Recently, improvement of analytical technologies has facilitated advanced speciation including determination of the information on detailed structure for the metal complexes. This review presents the dominant species of precious metal complexes in cyanogen, hydrochloric acid, and nitric acid solutions, and their leaching systems. In addition, conventional and current speciation methods are discussed.
Recycling of precious metals is becoming increasingly important as our living standards improve and technologies advance. In most cases, recycling processes of precious metals involve ionization steps to dissolve them in some solvents. Since precious metals are highly chemically stable (i.e. their ionization energies are large), a combination of a strong complexing agent and an oxidizing agent is required to dissolve them in the solutions. Furthermore, scraps contain many elements. The recycling processes to separate and purify precious metals consist of many complicated steps, and thus, these processes are time consuming and generate large amounts of hazardous waste liquid and gases. Therefore, a novel process to recover precious metals from scraps, which is simple and generates small amount of hazardous waste liquid, is desired. Recently, we have developed a new process to recycle precious metals utilizing anodic electrochemical deposition from anionic ions of precious metals dissolved in a molten salt electrolyte. This new process is simple and does not generate harmful waste; thus, it is efficient and environmentally-sound. This article introduces the newly developed recycling process utilizing anodic deposition, with its background, related previous research, and future prospects.