The washing process after plate and frame filtration is extremely slow – I would like to ask the experts for the reasons and solutions
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Make a batch of molybdenum slag now. Sodium carbonate is used for leaching, under conditions of 1.5 kilograms of pressure and a temperature of 130 degrees. During the production process, it was found that the plate and frame filtration was functioning properly; the pump used for operating the plate and frame system has a flow rate of 32 cubic meters per hour and a head of 40 meters. However, when filtering the backwash water, the flow rate is extremely low – only about 3 cubic meters per hour. This is even for a filter cloth that has just been thoroughly cleaned; if the filter cloth is not cleaned two or three times, the backwash speed becomes even slower. I use a pump with a capacity of 25 cubic meters and a lift height of 32 meters for washing; the water enters the pump through a towerless water supply system, which provides a pressure of 2 kilograms. I have a question: could it be that the raw material is too fine and thus clogs the filter cloth, preventing water from passing through? Are there any other possible reasons? Is there any way to solve this problem? I hope experts can offer some advice. Not grateful.
Check whether the filter cloth is installed correctly? The large pores might have been blocked.
There is no problem with the filter cloth; it’s a device that has been in normal use all along. Additionally, when the flow rate is too low, we will thoroughly clean the filter cloth, and its flow rate will be higher at first after cleaning.
““The flow rate of the wash water is extremely low after filtration” – does the flow rate suddenly decrease after filtration, or does the flux of the filter keep decreasing throughout the filtration process? ? “There is no problem with the filter cloth; it’s a device that has been in normal use all along. Additionally, when the flow rate is too low, we will thoroughly clean the filter cloth, and its flow rate will be higher at first after cleaning. ”——If there is no significant change in flow rate, then it’s definitely not a problem with the filter cloth. Could it be due to an issue with the equipment itself? Or is the pressure difference for filtering insufficient? Of course, the fact that you mentioned the raw materials being too fine is a possible reason for the clogging of the filter cloth; it’s also possible that the fine texture of the raw materials results in excessive resistance in the filter cake
First, determine what the mesh size of the filter cloth is; it is recommended to try replacing it with a different one! Check whether the flow channels of the filter plate are blocked! Check if there is a problem with the pump’s impeller!
Adjust the pressure and give it a try; also check if your pressure guide tube is blocked
There could be several reasons for the low washing water flow: 1. The material is too sticky, making it difficult to filter and thus hard to wash； 2. The filter cake is too thick, resulting in excessive resistance ； 3. The air permeability of the filter cloth is too low ； 4. Filter cloth clogging ； 5. The washing pressure is too low ； 6. Filtration through the filter cloth causes blockage of the filtration channels on the surface of the filter plate ； The slower speed you mentioned when it’s not washed two or three times is probably due to a clogged filter cloth.
Thank you all. I guess the material is too fine and has clogged the filter cloth. I’m asking everyone for some simpler solutions to this problem. Can a filter aid or something else be added to the slurry to solve this issue?
Another possibility is that the feed valve is opened too wide when the machine is started, resulting in high flow rates and pressures that compress the filter cake in a short time and cause a decrease in flux； Additionally, a low flow rate during washing may be related to the high level of impurities in your material.
Consider replacing the filter cloth with one having a lower mesh count. You need to test first to see if using a new filter cloth will result in defective product quality.
There are too many impurities, which causes rapid clogging. It is recommended to use self-cleaning filters; they occupy less space, provide fully enclosed filtration, require no electricity, generate little noise, have a higher processing capacity than plate-and-frame filters, and offer a filtration precision of 15 microns to 1140 microns
I think it’s a problem with the filter cloth. What model of filter cloth are you using?
You can try adding an appropriate filter aid to solve this problem. If that still doesn’t work, then considering a different filtration method is necessary; if a long service life for the filter fabric is desired, a coated tube bundle filtration system should be chosen. Microfiltration systems are also an option; they are inexpensive, but the flow rate at the outlet drops rapidly, and the filter element needs to be replaced more often.