Cobalt sulfate for aluminum removal
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My original cobalt sulfate solution contained 0.013% aluminum ions, with a pH of around 3. I adjusted the pH to 5.5 using ammonium bicarbonate to induce precipitation; after filtration, analysis showed that there was still 0.012% aluminum ions present. What’s going on here? Theoretically, the concentration of aluminum ions should be around 1 P
If theoretical data worked perfectly, then why would anyone go to the trouble of studying and optimizing process conditions? When inorganic ions precipitate, the salt effect is also an important factor. Furthermore, the formation of precipitates and precipitation itself belong to two completely different concentration ranges. The theoretical value refers to a single-component system of aluminum hydroxide; however, in actual industry, such a system basically does not exist.
Use some cobalt hydroxide precipitation to adjust the pH; it’s difficult to achieve 1 milligram using this method. A pH of over 6.3 can ensure 5 milligrams, but there is significant loss of cobalt, so recovery needs to be considered
Such tasks require sampling to determine process parameters in the laboratory; performing them directly on the production line is inefficient
Removal by co-precipitation with ferrous sulfate can reduce the level to 50 ppm; if a lower level is required, P204 should be considered.
Recently, I’ve been busy. The friend on the 3rd floor made an analytical error; the theoretical basis was correct. After multiple analyses, it was determined that there are 8 P atoms per aluminum ion