Diatomite has a unique shape and structure, a variable particle size range, stable chemical properties, strong adsorption capacity, non-toxicity, high-temperature resistance, and insoluble properties.
The practice has shown that using diatomaceous earth as a filter aid can not only increase filtration efficiency and improve clarity but also greatly simplify filtration equipment and operations. Therefore, it is widely used in industrial water treatment, the petrochemical industry, chemical fiber, paint, lubricants, and gelatin. And even the departments of pharmacy, pond making, food and beverage, brewing, and so on.
Industry often needs to use filtration methods to separate the mixture of liquid and solid. With the increasing sub-level of the modern chemical industry, especially the development of the fine chemical industry, filtration technology is also continuously improved and developed.
The so-called filter aid is an auxiliary powdery substance added when filtering materials. This substance can change the characteristics of the filter cake, and play a role in promoting material filtration. Diatomite has a unique physical structure, a variable particle size range, and stable chemical properties. Using diatomite as a filter aid can greatly increase filtration efficiency and improve clarity. It is more superior to cotton cake filtration. Therefore, this filter aid is used more and more widely in contemporary industry.
Diatomaceous earth, also known as diatomaceous earth, is a fossil of a single-celled phytoplankton diatom with a high content of silicon. Diatoms can survive in both fresh and saltwater. Their remains are deposited on the bottom of lakes or on the seabed. After long-term geological changes, the organic part of the algae is decomposed, and the accumulation layer of remains becomes a soft and fragile layer with the very high silicon content. High diatomite deposits.
There are many types of diatoms, and their silicon shells are also diverse, such as disc-shaped, cylindrical, needle-shaped, rod-shaped, and so on. They all have a porous structure, and there are countless large pores arranged in a honeycomb pattern on the silicon shell. There are a large number of micropores and multiple holes of various shapes. As a filter material, it is to make use of their porous characteristics. Generally, the porosity of diatomaceous earth is 80-90%.
Characteristics of diatomaceous earth
- Good stability. Thermal stability and strong chemical stability to strong acids and weak bases (except fluoric acid and strong bases). Filtration is not a chemical action, but a mechanical action, so the use of diatomaceous earth filter aid will not affect the basic properties of the original solution.
- Diatomite filter aid has porosity, variable particle size range and hard framework, so it can obtain a higher filtration rate and ideal clarity, and has a wide range of applications.
- Diatomaceous earth filter aid has a strong adsorption capacity, can filter out the miscellaneous particles below 1 m, including microorganisms and bacteria, and can obtain a good filtering effect for various alcohols, beverages and drugs that need to be filtered.
Diatomite filter aid is one of the most common and effective filter media in the current industrial filtration.
Application of diatomite filter aid in industrial filtration
Diatomaceous earth filter aids have excellent effects on filtering industrial liquids in the pharmaceutical, sugar, petrochemical, paint, lubricating oil, gelatin, food and beverage, and brewing sectors.
- Diatomaceous earth can be used to filter water, such as industrial water, urban drinking water filter element and swimming pool water treatment filter element, etc. It is also used to remove impurities such as iron oxide, sludge, and bacteria, and to adsorb and decolorize industrial wastewater, such as phosphoric acid plant filtering phosphorus-containing wastewater.
- In the production and filtration of gelatin, filter with diatomaceous earth filter aid to remove the non-collagen protein and other colored organic matter in the gelatin to improve the transparency of the gelatin. It is an excellent filter aid for the preparation of inert gum, deionized gum and low calcium gum in the gelatin industry.
- Add the diatomaceous earth filter aid to the washing liquid (usually an organic solvent such as trichloroethylene or tetrachloroethylene), and the flocculent diatomaceous earth filter aid forms a very thin pre-split layer on the filter element , The dirt and fluff in the filtrate are adsorbed by diatomaceous earth to form a porous filter cake to improve the filtration rate and clarity. The diatomaceous earth filter aid is covered by the dirt from the laundry and is exhausted after it reaches saturation. The washing liquid passes through the pores of the filter element to become a clear liquid and is recycled. It has lower energy consumption and simple operation than steam distillation to recover washing liquid.
- Diatomaceous earth has been widely used in beverage filtration.
At present, about 70% of diatomaceous earth filter aids abroad are used for beverage filtration. Domestic diatomaceous earth filter aids have been widely used in the filtration of beverages and general alcohol. Use diatomaceous earth filter aid to filter beverages If juice, pineapple juice, plum juice and alcohol (wine, sparkling wine, pear wine, etc.), the filtrate is clear and clear, the taste is pure, and the filtration effect is better than general clarifiers.
At present, diatomaceous earth filter aids are widely used in beer filtration. Relatively speaking, beer filtration requires higher performance of filter aids. At present, filter aids used in beer production are mainly imported. They are being developed in China, and our institute has also done a lot of work.