How to remove silicon and aluminum from saltwater
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Dear friends from Sichuan, how can silicon and aluminum be removed from brine?
Silicon and aluminum in brine can be removed using reverse osmosis technology. Reverse osmosis technology is a method that uses a semipermeable membrane to filter saline, separating solutes from water. In reverse osmosis equipment, brine is forced into a semipermeable membrane by a high-pressure pump, allowing water to pass through the membrane while solutes remain trapped on it, thereby achieving the removal of silicon and aluminum from the brine. .
May I ask you: are there any practical examples of its application? In chlor-alkali production, the volume of brine is quite large. How high are the costs associated with reverse osmosis treatment using high-pressure pumps? What happens to the silicon and aluminum that are removed during this process—do they remain in ionic form or are they filtered out as solids?
I also want to know if it works with saltwater of high concentration as well Are there any cases?
First, for membrane insertion, the silicon content must be at least below 30; otherwise, it will cause blockages as well. The second reverse osmosis membrane serves a concentrating function; as a result, the saltwater reaches a high concentration, accelerating the time at which the membrane gets clogged. Third, if the goal is only to remove silicon and aluminum, using membranes will fail; unless money is no object, pretreatment for removal will suffice
Rather than spending effort on finding ways to remove it, it’s better to find ways to prevent it from occurring in the first place.
The solubility product constant of aluminum hydroxide is very low (10^-33). The pH range at which trivalent aluminum ions precipitate is 5.5 to 8.5; therefore, maintaining a pH of around 7 allows aluminum ions to form aluminum hydroxide flocs, which can be removed through filtration or air flotation； Silicon can be removed by adding magnesium salts, which generate a large amount of magnesium hydroxide at pH 10–11 that acts to adsorb and carry it away.
By asking like this, how can those pretending to be experts answer? If you only have a basic understanding of the principles behind reverse osmosis and know nothing at all about the operational characteristics of saltwater purification processes, it will be very difficult for you
Could the silicon-aluminum issue be the cause of the silicone-like substance sticking significantly to the feed pipe, leading to an uncontrolled increase in tank voltage?