Auferstanden aus der Asche
Coal ash, fertiliser and even seawater may provide nuclear fuel Kohle Asche, Dünger und sogar Meerwasser kann vorsehen Kernbrennstoffen
Apr 8th 2010 | From The Economist print edition 8. April 2010 | Von der Economist-Druckausgabe
ONE of the factoids trotted out from time to time by proponents of nuclear power is that conventional coal-burning power stations release more radioactivity into the environment than nuclear stations do. ONE der factoids trabte von Zeit zu Zeit von den Befürwortern der Atomkraft ist, dass konventionelle Kohle-Kraftwerke mehr Radioaktivität in die Umwelt freigesetzt, als Kernkraftwerke zu tun. The reason is that the ash left over when coal is burned contains radioactive elements, notably uranium and thorium. Der Grund dafür ist, dass die Asche übrig bleibt, wenn die Kohle verbrannt enthält radioaktive Elemente, insbesondere Uran und Thorium.
Turn that logic on its head and it suggests that such ash is worth investigating as a source of nuclear fuel. Schalten Sie, dass die Logik auf den Kopf, und es legt nahe, dass diese Asche Untersuchung wert als eine Quelle von Kernbrennstoffen ist. And that is exactly what Sparton Resources, a firm based in Toronto, is doing. Und das ist genau das, was Sparton Resources, eine Firma mit Sitz in Toronto, tut. It has signed a deal with the China National Nuclear Corporation (CNNC), the authority that runs the country's nuclear-power stations, to recover uranium from coal ash at a site in Lincang, in Yunnan province. Es hat einen Deal mit dem China National Nuclear Corporation (CNNC), die Behörde, dass die Landes-nukleare Kraftwerke betreibt, unterzeichnet, um Uran aus Kohleasche wieder an einem Standort in Lincang, in der Provinz Yunnan.
Uranium is usually extracted from ore that contains 1,000 or more parts per million (ppm) of the element. Uran wird in der Regel aus Erz, 1.000 oder mehr Teile pro Million (ppm) des Elements enthält, extrahiert. The Lincang coal ash holds much less, about 300ppm. Die Lincang Kohleasche hält viel weniger, etwa 300ppm. That said, it does not need to be mined—which brings costs down. Das heißt, es muss nicht sein abgebauten die Kosten senkt. Sparton says it can extract a kilogram of uranium for $77 or less. Sparton sagt, es kann ein Kilogramm Uran für $ 77 oder weniger zu extrahieren. Uranium's spot price is now near $90 a kilo. Uranium Spotpreis ist jetzt in der Nähe von 90 Dollar pro Kilo. That is not a huge margin, but it is a profit nonetheless. Das ist nicht eine sehr große Spanne, aber es ist dennoch ein Gewinn.
To extract the uranium, Sparton adds sulphuric and hydrochloric acids to the ash, along with water, to make a slurry. Zur Extraktion des Urans, fügt Sparton Schwefelsäure und Salzsäure, um die Asche zusammen mit Wasser, um einen Schlamm zu machen. With some sorts of ash, nitric acid is also used. Bei einigen Arten von Asche ist Salpetersäure verwendet. The acids dissolve the uranium, and various other things, leaching them from the ash. Die Säuren lösen das Uran, und verschiedene andere Dinge, Auswaschung sie aus der Asche. The trick is to get the dissolved uranium out of the resulting solution. Der Trick ist, die gelöste Uran aus der entstandenen Lösung zu erhalten.
Sparton's process uses a charcoal filter made from burned coconut husks to trap floating particles and eliminate organic compounds. Sparton's Verfahren wird ein Aktivkohlefilter aus verbrannten Kokosnußhüllen zu fangen schwebende Teilchen und Beseitigung organischer Verbindungen. The filtered solution is then passed through small beads of an ion-exchange resin. Die filtrierte Lösung wird dann durch kleine Perlen einer Ionenaustauscher-Harz übergeben. These selectively remove uranium ions while leaving the others behind—extracting about two-thirds of the uranium in the ash, according to the company. Diese Uran-Ionen selektiv zu entfernen während die anderen hinter-extrahierende etwa zwei Drittel des Urans in der Asche, nach Angaben des Unternehmens. The uranium is then dissolved from the beads using a solution of ammonium carbonate and precipitated as “yellow cake”, a mixture of uranium oxides. Das Uran wird dann von den Perlen mit einer Lösung von Ammoniumcarbonat gelöst und als "yellow cake", eine Mischung aus Uranoxid.
China is developing ash-mining for reasons of energy security more than economics, according to Wang Hongfang, a marketing manager at CNNC. China entwickelt ash-Bergbau aus Gründen der Sicherheit der Energieversorgung mehr als Ökonomie, nach Wang Hongfang, ein Marketing-Manager bei CNNC. The country wants to get uranium from “every possible channel”, Mr Wang says. Das Land will Uran aus "allen möglichen Kanal zu bekommen", sagt Herr Wang. These include stripping it out of the tailings from gold and copper mines, and also from phosphoric acid produced during the manufacture of fertiliser. Dazu gehören Strippen es aus dem Bergematerial aus Gold-und Kupferminen, und auch von Phosphorsäure bei der Herstellung von Dünger produziert. Nor is CNNC alone in this aspiration. Auch ist CNNC allein in diesem Bestreben. NUKEM, a German-American company that enriches and sells nuclear fuel, hopes soon to begin “mining” fertiliser in Florida. NUKEM, ein deutsch-amerikanisches Unternehmen, vertreibt und bereichert Kernbrennstoffen, hofft, bald "Bergbau" Dünger in Florida zu beginnen.
Some people are even turning to seawater as a source of uranium, in an eerie recapitulation of Fritz Haber's attempt to pay off Germany's first-world-war debts by extracting gold from the ocean. Manche Menschen sind sogar drehen, um Meerwasser als Quelle von Uran, in eine gespenstische Reprise des Fritz-Haber-Versuch zu tilgen Deutschland die erste Welt-Kriegsschulden durch Goldgewinnung aus dem Meer. Though seawater contains only three parts per billion of uranium, mostly in the form of uranyl tricarbonate, the element can be sucked out of it by ion exchange. Obwohl Meerwasser enthält nur drei Teile pro Milliarde von Uran, die meist in Form von Uranyl tricarbonate, kann das Element aus der es durch Ionenaustausch gelutscht werden.
Several organisations, including Japan's Atomic Energy Agency and the Bhabha Atomic Research Centre in India, are attempting to do so. Mehrere Organisationen, darunter Japan Atomic Energy Agency und die Bhabha Atomic Research Centre in Indien, werden versuchen, dies zu tun. Their methods include the use of strips of ion-exchanging plastic, braided with polystyrene to toughen them up. Ihre Methoden zählen die Verwendung von Streifen von ionenaustauschenden Kunststoff, mit Polystyrol geflochten, um sie abzuhärten. These are placed in wire cages and anchored in a current of seawater. Diese sind in Drahtkäfigen gelegt und verankert in einem Strom von Meerwasser. After a month or two, the plastic is removed and soaked in acid to dissolve the uranyl tricarbonate. Nach ein oder zwei Monate, ist der Kunststoff entfernt und eingeweicht in den sauren Uranyl tricarbonate aufzulösen. The solution is then treated to precipitate uranium oxide. Die Lösung wird dann behandelt, um Uranoxid Niederschlag.
At the moment, this process costs more than ten times as much as conventional mining, but some countries might regard that as a small price to pay for security of supply. Im Moment kostet dieser Prozess mehr als zehnmal so viel wie herkömmliche Bergbau, aber einige Länder betrachten könnten, dass ein geringer Preis für die Versorgungssicherheit zu bezahlen. Perish the thought that the supply is for anything other than providing fuel for civilian nuclear-power stations. Perish der Gedanke, dass das Angebot für etwas anderes als die Bereitstellung von Brennstoff für zivile Kernenergie-Kraftwerke wird
www.economist.com/science-technology/....cfm?story_id=15865280
Novel sources of uranium
Rising from the ashes
Coal ash, fertiliser and even seawater may provide nuclear fuel
Apr 8th 2010 | From The Economist print edition
ONE of the factoids trotted out from time to time by proponents of nuclear power is that conventional coal-burning power stations release more radioactivity into the environment than nuclear stations do. The reason is that the ash left over when coal is burned contains radioactive elements, notably uranium and thorium.
Turn that logic on its head and it suggests that such ash is worth investigating as a source of nuclear fuel. And that is exactly what Sparton Resources, a firm based in Toronto, is doing. It has signed a deal with the China National Nuclear Corporation (CNNC), the authority that runs the country’s nuclear-power stations, to recover uranium from coal ash at a site in Lincang, in Yunnan province.
Uranium is usually extracted from ore that contains 1,000 or more parts per million (ppm) of the element. The Lincang coal ash holds much less, about 300ppm. That said, it does not need to be mined—which brings costs down. Sparton says it can extract a kilogram of uranium for $77 or less. Uranium’s spot price is now near $90 a kilo. That is not a huge margin, but it is a profit nonetheless.
To extract the uranium, Sparton adds sulphuric and hydrochloric acids to the ash, along with water, to make a slurry. With some sorts of ash, nitric acid is also used. The acids dissolve the uranium, and various other things, leaching them from the ash. The trick is to get the dissolved uranium out of the resulting solution.
Sparton’s process uses a charcoal filter made from burned coconut husks to trap floating particles and eliminate organic compounds. The filtered solution is then passed through small beads of an ion-exchange resin. These selectively remove uranium ions while leaving the others behind—extracting about two-thirds of the uranium in the ash, according to the company. The uranium is then dissolved from the beads using a solution of ammonium carbonate and precipitated as “yellow cake”, a mixture of uranium oxides.
China is developing ash-mining for reasons of energy security more than economics, according to Wang Hongfang, a marketing manager at CNNC. The country wants to get uranium from “every possible channel”, Mr Wang says. These include stripping it out of the tailings from gold and copper mines, and also from phosphoric acid produced during the manufacture of fertiliser. Nor is CNNC alone in this aspiration. NUKEM, a German-American company that enriches and sells nuclear fuel, hopes soon to begin “mining” fertiliser in Florida.
Some people are even turning to seawater as a source of uranium, in an eerie recapitulation of Fritz Haber’s attempt to pay off Germany’s first-world-war debts by extracting gold from the ocean. Though seawater contains only three parts per billion of uranium, mostly in the form of uranyl tricarbonate, the element can be sucked out of it by ion exchange.
Several organisations, including Japan’s Atomic Energy Agency and the Bhabha Atomic Research Centre in India, are attempting to do so. Their methods include the use of strips of ion-exchanging plastic, braided with polystyrene to toughen them up. These are placed in wire cages and anchored in a current of seawater. After a month or two, the plastic is removed and soaked in acid to dissolve the uranyl tricarbonate. The solution is then treated to precipitate uranium oxide.
At the moment, this process costs more than ten times as much as conventional mining, but some countries might regard that as a small price to pay for security of supply. Perish the thought that the supply is for anything other than providing fuel for civilian nuclear-power stations.
