Vacuum Ceramic Filter Plate Common Exception Handling

- Nov 15, 2017 -

1) filter plate into the initial running often because at the time of manufacture, micro polluted and slightly low yield, high moisture, with the machine running to ultrasonic cleaning combined with chemical cleaning can be restored several times.

2) classes use filter initial, high yield, low water, and the shift ahead are low yield, high moisture. The dehydration yield and water content are related to the properties of the pulp and the permeability of the filter plate, as well as the pore size and porosity of the filter. The filter plate with good performance has narrow average pore size and much hole rate. Microporous material is not easy to be in the ultra fine particles into the jam (Guan Jian academic words: membrane pollution and poor performance), the filter plate although the flux is high, but the proportion is not transparent and uniform access hole, when the hole is large and the flux decline rate of pollution, is made into the beginning of production high yield low. With the aging of the filter board, this phenomenon will be gradually prominent, so we should first of all to solve the filter board material stability performance from the perspective of material science. Another factor is the change of pulp properties. When the middle classes have downtime, filter plate after cleaning flux recovery is better. In the dense pool at the bottom of aggregate settlement after high concentration of coarse aggregate is also the first to sink, so the filtering efficiency is very good, and the operation to shift thickener aggregate concentration decreased, floating mud slurry is also high, so is the shift of low output, high moisture.

3) the flux of filter plate is better, but the output is still low and the water content is high. The main factors are the particle size, concentration, mud content and filter vacuum degree.  The water performance after mineral cake formation (Academic key words: hydrophobicity) is the prerequisite for yield and moisture content. Fine granularity, high mud content is hydrophobic, when the filter plate and at the end of microporous filtering surface pollution, although it is also good for the flux of vacuum suction block are not large, the aggregate cake formation is on board the pollution (Academic Keywords: membrane fouling), and dehydration process of solid-liquid filter the separation operation is a process of clearing pollution -- pollution. Therefore, different kinds of ore material forming a hydrophobic filter cake after different thickness of the filter cake is not the same, to the time required for vacuum dry are not the same, once the formation of a certain thickness of the filter cake will not result in filter plate flux and infinite thickness, it is difficult to quickly suck dry moisture. But in general, the filter board has good permeability, and the filtration effect is also slightly better. In this case, we should focus on the pulp properties, mineral processing technology and dense form of reform. And if the slurry performance, filter plate flux is not high, often still can obtain satisfactory effect of the filter, but the area of vacuum on the dehydration effect is also affected.

4) the filter plate is blocked seriously and is not easy to clean.  One reason is that the microporous filter plate of the filter aperture is not uniform resulting, or filter plate with aging process, the membrane surface gradually wear, exposing the film microfiltration below the matrix pores, that has reached the service life of filter plate. Therefore, it is necessary to choose the material of the filter board to solve the problem, so as to prolong the service life as far as possible. Another reason is that the pH of the pulp is close to neutral, or because the slurry contains substances that are not easily eroded by nitric acid, or have viscosity and chemically stable organic matter. When the pH value of the pulp is close to neutral, the free metal ions in the slurry will cause scaling in the micropores of the filter plate. Some effective cleaning with nitric acid and some invalid, usually using oxalic acid or other acid spacer cleaning, can obtain satisfactory results, and appropriate increase of pulp alkalinity.

5) when the filter is running, the filter board is not uniform in the thickness of the cake, and even some parts don't suck the pulp. As a result of individual phenomenon is usually due to surface contamination or filter plate, filter plate uneven concave, blade each did not ideal for cake discharging, and the surplus is more, thin cake remaining and not once per turn washed off, after repeated several times, the site fully plummeted, resulting in slurry suction effect. When a lot of filter plate appearance of the situation in the past and did not appear, should check the pressure back flushing system, or the distribution valve (device) of the dynamic and static sealing sheet between the sealing operation state. When the backwash water pressure is too low (and larger flux filter plate) in the recoil pressure set, each filter plate can not be running a circle, flushing a required flushing water, which will lead to the repeated operation situation. Or the distribution valve (device) between dynamic and static sealing sheet on leakage, anti flush volume and pressure did not effectively applied to the filter plate cavity, will have this kind of situation. In addition the fine filtration film coated on the surface of the filter plate surface wear will also appear in the class, so the quality of filter plate membrane surface should be uniform thickness, smooth surface, smooth assembly, avoid the local too close to the blade.

6) the cracking of the filter plate and the bursting of the surface. When an individual phenomenon of cracking, should first check whether the plate under the action of external force and crack or break, and then check the filter material of body's strength has been compared with the new filter plate has great difference. If it has been aging, the service life of the filter plate has been reached, otherwise it will be damaged by external force. The surface burst is due to the internal structure, insufficient strength (refers to the use of shorter board surface) not aging, or with the aging process, the internal structure and strength gradually reduce drum crack. Usually when the filter plate is used for a certain period of time, the safe use period of the filter plate is indicated when the damage is frequent.

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