The issue of adding ferric trichloride in the saline pretreatment process
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This post was last edited by sunjl1981 on 2013-1-6 at 23:35. Some people on the forum say that the concentration of ferric chloride when added to saltwater should be between 50 and 150 ppm, but other sources indicate a range of 5 to 15 mg/l. The people from Kay Membrane suggested 3 l/m3 of saline. Which one is correct after all? And then there’s the color of the mud; some say it should be as light as possible, but what exactly counts as a moderate color? I would be very grateful if those who have a relatively stable pre-treatment process could share their company’s parameters (such as the ratio of raw salt to ferric chloride, and the color of the sludge) # ， ， &
Friend upstairs, I think there are a few points that need to be clarified: 1. The role of ferric chloride: As a flocculant, its effect is merely supplementary; in other words, the amount of ferric chloride added has no inevitable relationship with the quality of the water after pretreatment； But it will cause a change in the iron content in the saline solution ； 2. The amount of ferric chloride to add: This should be determined primarily based on the specific characteristics of the salt used. If you use refined salt, it may not even be necessary to add any ferric chloride (my senior at yzhms’ unit has experienced this) ； If you use low-quality salt, no matter how much you add, it won’t have much effect ； The several figures mentioned by the original poster all have their sources; the so-called 3 l/m3 refers to a concentration of 1% ferric chloride, or in other words, the actual amount used. 50-150 ppm refers to the concentration on a per hundred basis ； I have no idea where 5-15mg/l comes from ；
The addition rate of 1% ferric chloride at 3 l/m3 was taken from the KAI membrane process package. As for the range of 50–150 ppm, considering that 1 m3 of brine weighs 1200 kg, the amount of ferric chloride in that volume is 60–180 g; converted to 1% ferric chloride, this corresponds to 6000–18000 g, which is approximately 5–15 l of 1% ferric chloride per m3 of brine. This seems quite different from 3 l/m3.