Cell phones forgotten in drawers, old computers, cables, chargers, televisions, and household appliances that are no longer in use seem to have little value when viewed individually. However, when gathered in large quantities, these devices form veritable deposits of metals.
Copper, aluminum, iron, gold, silver, palladium, nickel, cobalt, and rare earth elements may be present in products we use every day. When these materials are discarded, a significant portion of the mineral resources used in their manufacture is also lost.
It is in this context that urban mining emerges: the recovery of materials found in products, buildings, vehicles, equipment, and waste accumulated in cities. But how much metal is actually in the devices we discard? And can this waste be considered the mineral deposits of the future?
Conventional mining seeks mineral resources in natural deposits located underground. Urban mining, on the other hand, seeks to recover materials that have already been extracted, processed, and incorporated into products used by society.
The concept is not limited to electronic devices. Vehicles, batteries, cables, solar panels, metal structures, and construction waste can also be part of what are known as “urban mines.”
In the case of electronic equipment, the process begins when a product reaches the end of its useful life. After collection, the equipment may undergo stages such as:
The similarity to mining goes beyond just the name. Just like ore extracted from nature, electronic waste must be identified, sampled, characterized, concentrated, and processed so that its materials can be returned to the production chain.
In 2022, the world generated approximately 62 million metric tons of electronic waste, according to the Global E-waste Monitor 2024. Of this total, only 22.3% was documented as having been formally collected and recycled in an environmentally sound manner.
This waste included about 31 million metric tons of metals, valued at approximately $91 billion. Copper alone accounted for about $19 billion; gold, $15 billion; and iron, $16 billion.
The report also estimates that global e-waste generation could reach 82 million metric tons by 2030. This means that the amount of waste being discarded is growing faster than the formal capacity for collection and recycling. Source: ITU and UNITAR
These figures help explain why municipal waste has come to be viewed as a secondary source of raw materials. While it does not replace a geological deposit, it represents a growing stockpile of materials that have already been extracted and are concentrated in cities.
An electronic device consists of various materials, each associated with a specific function.
Copper is used in cables, connectors, motors, and circuit boards because of its high electrical conductivity. Aluminum can be found in frames, heat sinks, and housings, while iron is used primarily in structural components.
Metals such as gold, silver, and palladium are used in small quantities in connectors and circuits due to their conductivity and corrosion resistance. Lithium, cobalt, nickel, manganese, and graphite, on the other hand, are important in the manufacture of various types of batteries.
Rare earth elements may be present in magnets, speakers, motors, screens, and other technological components. These include neodymium, praseodymium, terbium, dysprosium, and yttrium.
The recovery of metals from discarded products is already well established in some sectors. The steel industry, for example, has been using ferrous scrap as a raw material for decades. In Brazil, approximately 8 million metric tons of steel scrap were recycled in 2020. This volume accounted for approximately 30% of the steel produced in the country that year, demonstrating how material reuse is already an integral part of the national steel supply chain. The presence of a metal, however, does not mean that its recovery will automatically be feasible. Just as with a mineral deposit, it is necessary to evaluate concentration, available quantity, processing technology, costs, scale, and market value.
Although they are not minerals—since they do not constitute natural mineral deposits—discarded cell phones can serve as secondary sources of raw materials. In a single device, metals are present in small quantities. However, when thousands or millions of cell phones are collected, the accumulated volume of these materials becomes significant for recovery and recycling.
This comparison helps explain one of the principles of urban mining: the value lies not only in each individual device, but in the ability to collect large quantities of relatively homogeneous waste and direct it toward appropriate processing methods.
Furthermore, the concentration of certain metals in circuit boards is often higher than that found in some natural ores. This does not mean that their recovery is necessarily simpler or cheaper. The materials are mixed into complex components, and their separation requires technology, environmental controls, and operational scale.
The first step is collection. Without systems capable of retrieving devices from homes, businesses, and warehouses, the raw materials do not reach the treatment facilities.
Next comes sorting. Equipment that still works can be repaired, refurbished, or have its components reused. This possibility should be considered before recycling, as extending a product’s useful life generally preserves more value.
Materials destined for recycling proceed to disassembly and separation. Housings, cables, batteries, circuit boards, screens, and other components have different compositions and should not be processed in the same way.
After preparation, physical, chemical, or metallurgical processes may be employed. Magnetic separation, particle size classification, density separation, hydrometallurgical, and pyrometallurgical processes are some of the technologies that can be used in recovery.
The choice of process depends on the composition of the waste and the products to be obtained. Recovering copper from cables, for example, presents a different challenge than separating precious metals from circuit boards or recovering materials from a battery.
Despite its potential, turning electronic waste into raw materials involves significant obstacles.
In Brazil, the National Solid Waste Policy established shared responsibility for the life cycle of products. Subsequently, Decree No. 10,240/2020 set forth standards for the implementation of mandatory reverse logistics for household electrical and electronic products and their components. Source: Office of the President
Reverse logistics connects consumers, retailers, manufacturers, importers, distributors, operators, and recyclers. Its goal is to create a pathway for discarded products to return to the production system or be disposed of in an environmentally sound manner.
Brazil has a large population, significant consumption of electronic equipment, and a substantial industrial base. Consequently, it also has high potential for the development of urban mining. However, this potential depends on greater coverage of drop-off points, traceability, consumer information, and technological processing capacity.
Urban mining does not eliminate the need for conventional mining.
The expansion of electrical grids, renewable energy, electric vehicles, energy storage systems, and digital technologies is driving up demand for various mineral raw materials. At the same time, not all materials in equipment can be fully recovered, and some of them remain in use for many years before becoming available for recycling.
In this sense, the two activities can work in a complementary manner. Conventional mining provides the materials needed to meet current demand and technological growth. Urban mining recovers some of the resources already circulating in the economy, reduces losses, and enhances security of supply. The goal is not to choose between extracting and recycling, but to use mineral resources more efficiently throughout their entire life cycle.
The utilization of these secondary sources, however, varies significantly among countries. In 2022, Brazil generated approximately 2.44 million metric tons of electronic waste, but only 79,000 metric tons were formally collected—about 3.2% of the total. During the same period, this proportion was approximately 23% in Japan, 54% in Germany, and 63% in Switzerland. These differences reflect, among other factors, the stage of reverse logistics policies, collection infrastructure, and processing capacity in each country.
Urban mining shows that the value of mineral resources does not end once they have been transformed into products. Cell phones, cables, vehicles, metal structures, and other discarded goods form secondary stocks that can be recovered and reintroduced into the production chain. Despite this potential, recovery still depends on efficient systems for collection, reverse logistics, sorting, and processing. The differences observed among countries demonstrate that it is not enough for materials to be available: infrastructure, technology, regulation, and planning are needed to transform them into an effective source of raw materials.
Therefore, it does not replace conventional mining but expands the way mineral resources are managed. Integrating extraction, production, use, reuse, and recycling helps reduce losses, make better use of existing materials, and make the mineral supply more efficient and circular. More than just finding new deposits, the challenge now also involves recognizing and recovering the mineral value that is already all around us.
References
INTERNATIONAL TELECOMMUNICATION UNION; UNITED NATIONS INSTITUTE FOR TRAINING AND RESEARCH. The Global E-waste Monitor 2024. Disponível em: ITU.
BRASIL. Decreto nº 10.240, de 12 de fevereiro de 2020. Regulamenta o sistema de logística reversa de produtos eletroeletrônicos de uso doméstico. Disponível em: Planalto.
CENTRO DE TECNOLOGIA MINERAL. Mineração urbana: conceitos e análise do potencial dos resíduos eletroeletrônicos. Disponível em: CETEM/Mineralis.