Wat er werkelijk wordt vervoerd
Sulfide copper has to be smelted, and more than half the world's smelting capacity is on the other side of the Pacific. So Chilean concentrate — about 30% copper and 70% something else — sails 19,000 km to be turned into metal, and the by-products in it become somebody else's gold, silver and tellurium.
- Het materiaal
- Copper
- De variëteit
- Chalcopyrite concentrate from a porphyry, roughly 0.5% Cu ore grade
- Waar het begint
- Chile — Escondida, 3,100 m up in the Atacama
Stap voor stap, en grens voor grens
Chile · Escondida, Antofagasta in beheer bij BHP as operator, with Rio Tinto and JECO (Mijnbouwer)
Moving a mountain for half a percent
Drilled, blasted and hauled from an open pit. At about 0.5% copper, 995 kg of every tonne is waste before processing even begins.
Waarom hier: A porphyry orebody, and desalinated seawater pumped 180 km uphill to process it.
Chile · Concentrator in beheer bij BHP (Mijnbouwer)
Grinding and floating
Ground to a powder and floated: air bubbles carry the sulfide minerals to the surface while the rock sinks. The result is a concentrate of about 30% copper.
Wat er met de rest gebeurde: 984 tonnes to the tailings dam. Grinding is the largest single electricity consumer on any copper mine.
Waarom hier: Always at the mine. Shipping 1,000 tonnes to recover 5 would be indefensible.
China · Antofagasta to Chinese smelter ports in beheer bij Traders and smelters (Handelaar)
Down to the coast and across the Pacific
Concentrate moves by truck or slurry pipeline to the port, then in the hold of a bulk carrier. Treatment charges — what the smelter is paid to process it — are negotiated annually and are one of the industry's most watched numbers.
Waarom hier: Because the smelters are there. Chile smelts a minority of its own concentrate.
China · Guixi, Jiangxi in beheer bij Smelter (Raffinaderij)
Smelting
Melted with oxygen. Iron and sulfur oxidise away; the sulfur is captured as sulfuric acid rather than released. What is left is blister copper at about 98%.
Wat er met de rest gebeurde: The captured sulfur becomes sulfuric acid — often sold onward to leach nickel or phosphate somewhere else entirely.
Waarom hier: Smelting needs scale, an acid plant, an acid market and a permit. China assembled all four.
China · Tankhouse in beheer bij Refiner (Raffinaderij)
Electrorefining, and the slime at the bottom
Blister is cast into anodes and dissolved electrolytically over about two weeks; pure copper plates onto cathodes. Gold, silver, selenium, tellurium and platinum-group metals do not dissolve and settle as anode slime.
Wat er met de rest gebeurde: That anode slime is where a large share of the world's tellurium and selenium comes from. The by-products of this step are a whole industry.
Waarom hier: Refining follows smelting; the two are almost always on the same site.
China · Rod mill and cable plants in beheer bij Cable and equipment makers (Fabrikant)
Rod, wire, and a grid
Cathode is melted and drawn into rod, then wire, then cable. 4.6 tonnes is roughly the copper in one large wind turbine, or a few hundred metres of subsea export cable.
Waarom hier: Copper is one of the few materials here that can be recycled endlessly without losing quality. This tonne will outlive the mine.
Dit is een uitgewerkt voorbeeld. Het volgt een opgegeven beginhoeveelheid door gepubliceerde typische opbrengsten en rendementen, zodat de verhoudingen controleerbaar zijn; het is geen verslag van een concrete zending. Routefeiten — welke landen, welke processen, en waarom het materiaal niet zomaar elders kan worden verwerkt — zijn samengesteld uit openbare bronnen.