The removal of trace elements from dilute water solutions by hydroxide precipitates was investigated. The co-precipitation yields of manganese, cobalt, ruthenium, europium and protactinium onto beryllium, zinc, iron, lanthanum and titanium hydroxides were studied in the pH region from 3 to 11, while those of manganese, cobalt, yttrium, zirconium, niobium, ruthenium, europium, and protactinium onto the same hydroxides were investigated in sea-water media. The influence of some other factors, such as the presence of neutral electrolyte and NH4+ ions, aging of hydroxide precipitates etc. on the co-precipitation yields were also examined.

Preconcentration of manganese, cobalt, yttrium, zirconium, niobium, ruthenium, europium and protactinium by various hydroxides

The radioactive tracer method has been applied for the investigation of the influence of citric acid and amino-acids on the coprecipitation yield of cobalt traces with aluminium hydroxide precipitates. Results indicate that the presence of citric acid decreases the coprecipitation yields when 7 > pH > 8.5. Amino-acids decrease the cobalt coprecipitation yield at pH values above their isoelectric point. However this could be valid only for amino-acid concentrations above 10−4
M. Results also indicate pH regions where certain cobalt species could be separately coprecipitated on the basis of different coprecipitation yields.

P. Strohal

Papers

Coprecipitation of cobalt in the presence of aminoacids and citrates