Removal of silicon from high-acid leach solutions?
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Dear experts, the raw material contains Fe, Zn, and SiO2; after high-acid leaching, the final pH is below 1. The solution has good filterability, but an increase in pH results in the formation of a large amount of colloids. The silicon content in the liquid is around 1 g/l. What methods can be used to remove this silicon?
Use MgCl2+AL2(SO4)3 to adjust the pH to around 8, then precipitate Si or use ion exchange/extraction; first extract Fe and Zn and analyze Si
Reply to 2# pj1987cool: Adjusting the pH to 8 will cause both zinc and iron to hydrolyze; even by using lime to adjust it to 2.0, a colloid is formed.
Silicon removal communication dscheny@126.com
Reply to 4# dscheny: Well, when conducting experiments, such problems arise. Please give me some advice; it seems that using NaOH works better.
Sodium fluoride is used at high temperatures, and then by cooling, the resulting sodium fluorosilicate is precipitated and filtered out
Apart from removing silicon, at certain leaching conditions, silica can be generated directly; there’s no need to adjust the pH value at all, and the results are still good
Reply to 7# Hydrometallurgy: Hello, I would appreciate your advice. How can we control the process during leaching so that silica is formed instead of silicic acid? After just two days, the mixture turns jellied.
Reply to 7# Wet non-ferrous metallurgy: Oh, right – during leaching, silicic acid is formed. Our factory has encountered this problem as well; it not only affects filtration but also causes the filter cloths in the plate and frame filters to wear out easily, and ultimately the silicon isn’t removed
Silicon can be removed by adding flocculants or adjusting the pH
Your solution doesn’t contain just silicon, right? What about the levels of other impurities? I guess the iron content is high