Regarding water glass/activated silicic acid, is there any water treatment plant that uses it as a coagulant?
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This post was last edited by cdpulin on 2011-8-24 at 17:02. Recently, I’ve come across many sources discussing the use of water glass as a coagulant aid, but they only cover things such as the dosage of water glass as a coagulant aid and its advantages; none of them explain the process of preparing water glass as a coagulant aid. How can it be configured as a solution? Then what dosing process should be used? Thanks for the help!
Here, we use water glass as a flotation reagent for mineral processing. Hehe, it’s in liquid form. Hehe; I’ve never heard of it being used as a flocculant, though. Hehe~~~
Reply to 2# llyy0327: According to information found online, coagulants are used in water treatment plants; after all, PAM cannot be used in such plants.
This post was last edited by cdpulin on 2011-8-25 at 10:54. Activated water glass (also known as sodium silicate) is a coagulant used to enhance the structural components of alum flocculates and to modify their structure. The activation method for water glass involves preparing it as a 3%-5% aqueous solution (preferably as a 1.5% silicic acid solution), and then slowly adding industrial sulfuric acid while stirring, so as to maintain the alkalinity of the solution at an appropriate level of 1200 mg/L to 1500 mg/L (based on calcium carbonate). The activation time is about 4 hours; the solution should be in an emulsified state, and it becomes ineffective if it freezes into clumps. The dosage basin for water glass is related to the turbidity of the raw water, its pH value, and the silica content in the water. It is necessary to conduct experiments prior to selection in order to determine the optimal dosage. The dosing point should be located before the coagulant dosing point. In water treatment plants where PAM is not used, it is a wise choice to employ activated water glass as a coagulant aid.
Reply to 4# cdpulin: Is the activation method for water glass that complicated? It’s impossible to add water glass to a water treatment plant, right? Should I just buy the activated liquid formulation? But it’s also stated that it must be used up as soon as possible after activation……
Reply to 5# 2887848: It seems complex, but the actual operation is simple. After more time of activation or more repetitions, and with gained experience, it will be done correctly. You can buy pre-activated finished products, but the price is a concern. If you want to spend less money, activate it yourself; if you want to save effort, spend more money on pre-activated products.
Reply 6# cdpulin, right too! Also, should water glass be added before the coagulant? Are there any special considerations regarding the material of pumps and pipes when adding it? Using UPVC should be fine, right?