How to wash the filter cake during the suction filtration process

Decompression filtration: Principle: The suction pump depressurizes the suction filter bottle, resulting in the pressure difference between the bottle and the liquid surface of the Brinell funnel, so as to speed up the filtration speed. Install the instrument, put the filter paper into the Brinell funnel and use distilled water.

Wet the filter paper, turn on the faucet slightly, and pump air so that the filter paper adheres to the funnel porcelain plate. Use the decanting method to transfer the solution first, turn on the big faucet, and then transfer the precipitate when the solution is almost exhausted. When the liquid level in the suction filter bottle is about to reach the position of the branch nozzle, pull out the rubber tube on the suction filter bottle and pour the solution from the upper mouth of the suction filter bottle.

When washing the sediment, the small tap should be turned off so that the detergent can pass through the sediment slowly. Precautions: The size of the filter paper put into the Brinell funnel should be smaller than the inner diameter of the funnel and cover all the small holes.

The amount of solution poured into the Brinell funnel should not exceed 2 3 of the funnel capacity. When the filtered solution is strongly acidic, alkaline, or strongly oxidizing.

, it will corrode the filter paper, and glass fibers can be used at this time.

Replace filter paper or use glass sand.

The funnel replaces the Brinell funnel. When the suction filtration is completed or the suction filtration needs to be stopped in the middle of the process, attention should be paid to remove the rubber tube connecting the suction pump and the suction filter bottle first, and then turn off the faucet to prevent suction. Vacuum filtration should not be used to filter colloidal precipitation or precipitation with too small particles, colloidal sedimentation.

In the laboratory, there are generally two ways: one is to directly add washing liquid to the filter cake and then suction filtration, and the way to add washing liquid can be continuous addition, while adding and pumping; It can also be added to a certain amount, and then smoked, and then added and smoked. The second is to transfer the filter cake out, crush, add washing liquid to slurry again, and then suction filtration, this method can also be repeated.

If the product is a filter cake, the second method is better than the first method.

Influence of cake washing and blowing on the entire operation process of filtration:

The intrusion of solid-phase particles is caused by the filtration of the working liquid, and the filter cake formed during the filtration process in turn controls the intrusion of the working liquid. The faster the cake is formed and the better the quality, the less intrusive solids particles and the less damage to the reservoir.

Just pay attention when washing:

1. Do not stir the filter cake with a glass rod, otherwise the filter cake will be loose and the filtration effect will be poor; In addition, there is a risk of puncturing the filter paper.

2. In order to wash evenly, it is best to use glass rods to drain to achieve uniform rinsing.

The purpose of cake washing:

It is to replace the residual mother liquor in the filter cake and absorb the impurities in the filter cake to the greatest extent possible with as little washing liquid as possible. Therefore, it is necessary to prevent the "short circuit" of the washing liquid during the washing of the filter cake, so the following points should be paid attention to during the washing operation: the washing liquid should be sprayed on the surface of the filter cake as evenly as possible, and the rate of adding the washing liquid should be as consistent as possible with the rate of flowing out of the filter cake.

If the addition rate is too small, the washing cycle time will be prolonged, and the washing liquid will be difficult to distribute evenly. When the addition rate is too large, it is easy to damage the filter cake structure and cause a "short circuit". For incompressible or near-incompressible filter cakes, washing can be performed with a higher separation factor, which is conducive to speeding up the discharge rate of the washing liquid and saving washing time.

The above content reference: Encyclopedia - filter washing.

Summary. Yes, when using oven filtration, the cake and paper need to be separated, the cake transferred to a beaker and dried. This is to remove water from the filter cake for subsequent experiments or analysis.

Yes, when using oven suction filtration, the cake and paper need to be separated, and the cavity hail cake is transferred to a beaker and dried. This is Wu Doufan's attempt to remove the water pin in the filter cake for subsequent experiments or analysis.

Can you elaborate on that a little bit more?

Oven suction filtration is a method of separating solids and liquids from a mixture, by using a vacuum suction filter to filter the mixture through the filter paper, leaving the solids on the filter paper to form a filter cake, while the liquid flows out through the filter paper and collects in a beaker. Before drying, the cake and paper need to be separated, usually using a spatula or tweezers to peel the paper from the cake and separate it. After stripping, the cake needs to be transferred to a beaker for drying.

The purpose of drying is to volatilize the water in the filter cake during combustion for subsequent experiments or analysis. Usually an oven is used for drying, the filter cake is placed in a preheated oven, the temperature and time are controlled, and the moisture in the filter cake is completely volatilized, and then taken out for subsequent treatment. It should be noted that in the process of transferring the filter cake to a beaker for drying, it is necessary to avoid external contamination and impurities as much as possible, so as not to affect the results and reliability of subsequent experiments.

Therefore, when transferring the filter cake and filter paper, it is necessary to keep the environment clean and closed as much as possible.

Summary. Typically, the cake and paper are separated when using oven suction filtration so that the cake can be transferred to a beaker for further processing.

Typically, the cake and paper are separated when using oven suction filtration so that the cake can be transferred to a beaker for further processing.

Can you add, I don't quite understand it.

When you use an oven for suction filtration, you usually need to use filter paper and filter cake. Filter paper is used to filter solid particles in the solution, while filter cake is the solid substance that remains on the filter paper. After the slurry, you need to separate the cake from the paper, you can transfer the cake to a beaker and then dry it.

In this way, you can separate the cake from the paper and collect the cake in a beaker. After drying, you can further process the cake using the desired method. This can help you get more accurate and reproducible results.

The role of cake washing:

By washing, the effective ingredients in the filter cake can be further cleared, or the harmful components can be removed or halled.

The role of the blowing process.

If the filter cake needs to be blown off, compressed air can be introduced through the scrubber hole to remove some of the moisture from the filter cake.

One sticker: refers to the filter paper should be close to the funnel wall, generally when the filter paper is pasted on the funnel wall, wet with water and squeeze out the bubbles, because if there are air bubbles will affect the filtration speed

Two low: first, the edge of the filter paper should be slightly lower than the edge of the funnel; Second, throughout the filtration process, it is necessary to always pay attention to the liquid level of the filtrate to be lower than the edge of the filter paper. Otherwise, the filtered liquid will flow down from the gap between the filter paper and the funnel and flow directly to the receiver at the bottom of the funnel, so that the unfiltered liquid is mixed with the filtrate, and the filtrate is turbid, and the purpose of filtration is not achieved.

Three reliance: first, when the liquid to be filtered is poured into the funnel, the beaker spout of the beaker containing the liquid to be filtered should lean against the inclined glass rod (glass rod drainage); The second is that the lower end of the glass rod should be leaning on the side of the three-layer filter paper (one side of the three-layer filter paper is thicker than the one layer of filter paper, and the three-layer filter paper is not easy to be broken); The third means that the neck of the funnel should be close to the inner wall of the receiver receiving the filtrate.

34.Through backwashing, the particle size of the filter cavern material always increases gradually from top to bottom, which is the effect of (b).

a. Hydraulic scouring; b. Hydraulic screening; c. Filter media rub against each other; dGravity. Answer: b If you approve of me, please be in time, if you approve of me, please click the [Answer for Satisfactory Return] button in time.

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When filtering operation, we should pay attention to the principle of "one stick, two low, and three leaning", and the role of the glass rod in the experimental process is drainage

The filtrate is still turbid after filtration, which may be due to damage to the filter paper (which will cause the insoluble matter in the liquid to enter the beaker below, thus making the filtrate turbid), the liquid level is higher than the edge of the filter paper (will cause some of the liquid to flow down directly without filtering the filter paper, and this operation will make the filtrate remain turbid), or the beaker containing the filtrate is not clean

So the answer is: drainage; Broken filter paper, etc