[Soda ash knowledge] Daily question (154) 2010.3.16

The crystal slurry taken out from the carbonization tower contains about 45% to 50% (V) of suspended solid NaHCO3, which is separated by filtration during production. The solid NaHCO3 after separation and washing is calcined, and the mother liquor is sent to the hydrogen recovery system. 1. Filtration and separation equipment There are two types of filtration and separation that are often used in the alkali production industry.: That is, vacuum separation and centrifugal separation, the corresponding equipment are vacuum filter and centrifugal filter respectively. Centrifugal separation uses the principle of centrifugal force to separate liquids and solids. This kind of equipment has a simple process, low power consumption, and the filtered solid heavy alkali has low water content (can be less than 10%). However, it has high requirements for the particle size of the heavy alkali, low production capacity, and high ammonia consumption. It is rarely used by large domestic manufacturers. Vacuum filtration uses vacuum to create a pressure difference on both sides of the filter cloth. The solid filter cake remains on the filter cloth and the filtrate is sucked away from the filter cloth. Vacuum filtration of heavy alkali uses a vacuum drum filter. During operation, the inside of the drum is drawn to a negative pressure by a vacuum machine, and the mother liquor is drawn into the drum to form a stream and is exported. The heavy alkali solids adhere to the filter cloth on the drum surface and are sucked dry. After being washed and squeezed, they are scraped off the filter cloth by a scraper and sent to the calcination process. The advantage of this method is that it can be operated continuously, has large production capacity, and is suitable for continuous large-scale automated production. The disadvantage is that the filtered heavy alkali has a high water content, generally around 15%, sometimes as high as 20%. The vacuum drum filter is mainly composed of a filter drum, an air disc, an alkali tank, a pressure roller, a scraper, a washing tank and a transmission device. The filter drum is mostly made of casting. There are many grids inside the drum connected to the air disc. There are many grate plates outside the drum. Felt is used as filter cloth on the plate. There are hollow shafts at both ends of the drum, and there are gears on the shafts connected to the transmission device. When the drum rotates once, it sequentially completes the processes of alkali absorption, drying, washing, squeezing, scraping and blowing, as shown in Figure 5-13. 2. Vacuum filtration process The process flow of vacuum drum filtration is shown in Figure 5-14. The crystal slurry alkali liquid flowing out from the bottom of the carbonization tower flows into the alkali tank of the filter through the alkali outlet tank 1. The filtrate is sucked into the filter drum by vacuum through the capillary pores of the filter cloth, and at the same time, it enters the separator 5 together with the sucked air. The gas and liquid are separated here, and the filtrate flows out from the bottom of the separator, enters the mother liquor storage barrel 6, and is sent to the ammonia recovery process through the pump 7. The gas comes out from the upper part of the separator and enters the lower part of the purified ammonia tower. The washing water added in countercurrent recovers NH3. The washing water flows out from the bottom of the tower into a fresh liquid barrel for use in calciner gas washing. The gas comes out from the top of the tower and is emptied. The heavy alkali on the filter cloth is sucked dry, washed, squeezed dry, scraped off and sent to the calcination process.

The porous filter media (interlayer) is used to block the suspended solids (containing a large amount of NaHCO3) particles in the carbonated liquid, allowing the liquid to pass through, thereby separating the liquid from the solid.

The basic principle of heavy alkali filtration is to use porous filter media (interlayers) to block suspended solids (containing a large amount of sodium bicarbonate) particles in the carbonated liquid, allowing the liquid to pass through, thereby separating the liquid from the solid.

The basic principle of heavy alkali filtration is to use porous filter media (interlayers) to block suspended solids (containing a large amount of sodium bicarbonate) particles in the carbonated liquid, allowing the liquid to pass through, thereby separating the solids from the liquid.

The basic principle of heavy alkali filtration is to use porous filter media (interlayers) to block suspended solids (containing a large amount of sodium bicarbonate) particles in the carbonated liquid, allowing the liquid to pass through, thereby separating the solids from the liquid.

The basic principle of heavy alkali filtration is to use porous filter media (interlayers) to block suspended solids (containing a large amount of sodium bicarbonate) particles in the carbonated liquid, allowing the liquid to pass through, thereby separating the liquid from the solid.

The basic principle of heavy alkali filtration is to use porous filter media (interlayers) to block suspended solids (containing a large amount of NAHCO3) particles in the carbonated liquid, allowing the liquid to pass through, thereby separating the liquid from the solid.

answer: The basic principle of heavy alkali filtration is to use porous filter media (interlayers) to block suspended solids (containing a large amount of sodium bicarbonate) particles in the carbonated liquid, allowing the liquid to pass through, thereby separating the solids from the liquid. 1# steinback

What is the basic principle of heavy alkali filtration? answer: The basic principle of heavy alkali filtration is to use porous filter media (interlayers) to block suspended solids (containing a large amount of NaHCO3) particles in the carbonation liquid, allowing the liquid to pass through, thereby separating the liquid from the solid.

The basic principle of heavy alkali filtration is to use porous filter media (interlayers) to block suspended solids (containing a large amount of sodium bicarbonate) particles in the carbonated liquid, allowing the liquid to pass through, thereby separating the liquid from the solid. 1# steinback