Material Insights · Understanding the Material World

Tantalum and Tin

Tantalum and tin come out of the same ground and the same furnaces: tin smelter slags are a tantalum source, both are dug by hand in eastern DR Congo and Rwanda, and both fall under the same conflict-minerals rules and electronics supply chains.

Tantalum (commodity) and Tin (commodity): 5 relationships.

How they are linked

1. Tantalum from tin slag

Joint production · Asymmetric · Tin smelting → tantalum-bearing slag

Some tin ores carry tantalum, which ends up in the slag when the tin is smelted; tantalum processors buy these slags as a raw material alongside mined concentrates.

USGS lists tantalum-bearing tin slags, mainly from Asia, Australia and Brazil, among tantalum's raw materials. Tin output therefore adds to tantalum supply, but tantalum prices do not decide how much tin is smelted.

Sources: USGS

2. Mined from the same deposits

Joint production · Medium · Shared ore bodies yield both

Tin and tantalum minerals often occur in the same deposits, so some mines produce both, with niobium and lithium as further coproducts.

Examples include Brazil's open-pit Pitinga tin, tantalum and niobium complex and the Mibra lithium, tantalum, niobium and tin mine. Coltan, the columbite-tantalite mineral mined in central Africa, is the leading tantalum ore, and it is often dug in the same areas as tin ore.

Sources: USGS

3. Central African artisanal supply

Geography and ownership · Strong · DR Congo and Rwanda supply both

Eastern DR Congo and Rwanda are major sources of both metals, much of it from artisanal and small-scale mines, so the same local conditions affect both supply chains.

  • 1,300 t DR Congo tantalum mine output, 2025 estimate, of about 2,500 t world
  • 400 t Rwanda tantalum mine output, 2025 estimate
  • 25,000 t DR Congo tin mine output, 2024 estimate, of about 300,000 t world

Africa is expected to remain the leading tantalum region, with output mainly from artisanal mines; for tin the region is a smaller share, so the overlap matters far more for tantalum. A June 2025 peace agreement between DR Congo and Rwanda was expected to improve conditions for regional mineral trade.

Sources: USGS; USGS; USGS

4. Conflict-minerals rules cover both

Policy · Strong · Same due diligence duties on importers

Tin, tantalum and tungsten, the 3Ts, plus gold are grouped in due diligence laws for minerals from conflict-affected and high-risk areas, so importers face the same checks on both metals.

  • 1 January 2021 EU due diligence duties for 3T importers applied from
  • over 2,000 mine sites covered by the ITSCI traceability scheme, about 2020
  • over 2,000 t a month 3T minerals traced by ITSCI

Shared schemes such as ITSCI tag tin and tantalum bags at the same mine sites in DR Congo, Rwanda and neighbouring countries, supporting about 80,000 miners. A failure of traceability in the region therefore affects both metals' access to European and US buyers at once.

Sources: International Tin Association; Pact

5. Electronics

Shared risk · Medium · Both sold into electronic components

Tin solder joins components to circuit boards and tantalum makes high-reliability capacitors, so electronics demand drives both.

  • 50% solder share of world tin use, 2022

An electronics downturn cuts demand for both together. Capacitor makers can switch to aluminium, ceramic or niobium capacitors, and tin has its own substitutes in packaging, so the shared exposure is to electronics volumes rather than to a fixed recipe.

Sources: USGS; International Tin Association

For investors

Key learnings

  1. Tin smelting and central African mining tie tantalum supply partly to tin, so tin market conditions can change tantalum feed.
  2. Both supply chains depend on artisanal mines in eastern DR Congo and Rwanda, so security there is a shared risk.
  3. Compliance with conflict-minerals rules is a cost and a market access condition for both metals.

What to track

  • Security and trade conditions in eastern DR Congo: Disruption risk for tantalum and part of tin supply (Monthly · UN and news reports)
  • Electronics and semiconductor output: Common demand driver for solder and tantalum capacitors (Monthly · industry data such as WSTS)

For policymakers

Key learnings

  1. Tin and tantalum are regulated together as conflict minerals, so one traceability system can cover both.
  2. Tantalum supply is far more exposed to central Africa than tin, so the same regional shock matters more for tantalum.
  3. Recovering tantalum from tin slags turns a smelter waste into a supply source, which is relevant for any country building tin smelting.

What to track

  • Responsible-sourcing audit coverage of 3T smelters: Share of supply meeting due diligence rules (Yearly · Responsible Minerals Initiative)
  • Tantalum mine output by country: Concentration of supply in DR Congo and Rwanda (Yearly · USGS Mineral Commodity Summaries)

Sources

  1. Mineral Commodity Summaries 2026: Tantalum, USGS (2026)
  2. Minerals Yearbook 2019: Tantalum, USGS (2022)
  3. Mineral Commodity Summaries 2025: Tin, USGS (2025)
  4. European Union's Conflict Minerals Regulation 2017, International Tin Association (2020)
  5. ITSCI: a decade of success, Pact (2020)
  6. ITA study: macro pressure rolls back tin demand, International Tin Association (2023)