FWIW, I was chasing after the “Fusion of Nickel and H2” topic and wondered “How much Nickel is there?”. If we start consuming it all, will that be a problem? Turns out to be a somewhat uninteresting “No. Nickel is one of the most abundant elements on earth or in the crust”. Much more than copper, so if we turn some nickel into copper “it’s a feature”…
But along the way I found that the USA is almost entirely dependent on non-US sources for Cobalt. Much of it from an unstable part of Africa that has now had the mines pretty much commit to being under contract to China.
As Cobalt is important for everything from “Nickel” batteries to catalysts to the magnets used in some high tech things, it is considered a “strategic mineral”. Not having any seems like a bit of “an issue”…
So I started looking for “alternative sources” and stumbled on this article from long long ago. About as old as I am. Starting from work done in 1953 and progressing forward to about 1969:
CONCENTRATION OF COBALT AND ZINC FROM SEAWATER USING
5,7-DIBROMO-8–HYDROXYQUINOLINE ( BROMO-OXINE ) SUPPORTED
ON AN ANION EXCHANGE RESIN
Carritt ( 1953) put forward an ingenious idea for concentrating trace metals from seawater using dithizone supported on a cellulose acetate column. He also demonstrated (Carritt 1964) that this reagent could serve the same purpose if supported on an anion exchange resin. Volumes (1-5 liters) of seawater containing either zinc-65 or cobalt-60 passed down a column ( DeAcidite FF + dithizone) were observed by me to be completely stripped of their cobalt and zinc content; but, when they were eluted with hydrochloric acid, the recovery of the adsorbed metals was incomplete (recovery of cobalt was 60% and of zinc 40%). It was thought that the retention of cobhydrochloric acid to destroy the cobalt-dithizone complex completely. The recovery of zinc was probably low due to readsorption of the zinc (as its zinc-chloro complex) onto the anion exchange resin. Work done on the concentration of trace metals from seawater using bromo-oxine ( Riley and Topping 1969) had indicated that the cocrystallized trace metals could be released from the organic complex by washing with dilute acid. In view of this, an investigation into the possible use of bromo-oxine in the way described by Carritt ( 1964) was initiated.
Preparation of resin column
The resin chosen for this work was the anion exchange resin, DeAcidite FF ( Cl-). A sample of the resin was washed with water and dried using acetone. It was then shaken with a solution of bromo-oxine in acetone ( 0.4%) for 30 min, dried, and a suspension of resin in water poured into an ion exchange column ( 8 x 0.5 cm), After settling, it was washed with three 50-ml portions of distilled water.
Investigation of cobalt and zinc adsorbed from seawater onto the resin column
Samples ( 1 and 5 liters) of filtered seawater (0.5 Jo) at its natural pH were equilibrated with several ,Gi of either carrier-free zinc-65 or carrier-free cobalt-60 and allowed to flow down individual resin columns. Retention of the ions was estimated by examining the eluate for activity; both cobalt and zinc were completely retained by the resin from both the 1 and 5 liter samples of seawater.
Elution of the adsorbed elements
Each column was washed with two 20- ml portions of distilled water to remove residual seawater. Dilute hydrochloric acid (0.2 N) was then passed down each column and the eluate monitored for radioactivity. Both cobalt and zinc were released from the resin column, a volume of 100 ml being necessary for complete removal of the cobalt but only 60% of the original zinc. On repeating the elution using 100 ml of 0.2 N sulfuric acid, the recovery of zinc was increased from 60% to 75%.
This preliminary investigation has demonstrated the use of the reagent bromooxine, supported on a resin column, as an effective method for concentrating trace amounts of cobalt and zinc from seawater. Using a small volume of dilute sulfuric acid, it is possible to elute all of the cobalt and 75% of the zinc off the column. This column, when suitably washed with distilled water, can be reused for further concentration steps. This method has the added advantage that the seawater does not have to be specially treated prior to the concentration stage.
Department of Civil Engineering,
University of Strathclyde,
CARRITT, D. E. 1953. Separation and concentration of trace metals from natural waters.
Anal. Chem., 25: 1927-1928.
-a 1964. Marine geochemistry : Some guesses and gadgets. R.I., Grad. Sch. Oceanogr., Narragansett Mar. Lab., Occas. Publ. 3(1965), p. 203-211.
RILEY, J. P., AND G. TOPPING. 1969. The use of 5,7-dibromo-Shydroxyquinoline for the concentration of certain trace elements from sea water. Anal. Chim. Acta, 44: 234-236.
Maybe with a bit of work this could be made simpler and even cheaper; but just as it stands the meaning is clear:
We can get all the cobalt we ever want from sea water, in a simple and clear way. All that changes is the cost (and that will not be very high given that the resin is reusable and “acid leaching” is a typical step in ore processing anyway). There are not a lot of added costs in this system.
G. Topping: I salute you for a Job Well Done!
Looks like one more (or two more if you include Zinc) “running out” scares can hit the dust bin of paranoid Malthusians…