A supergravity bed is a rotating bed with a filling material. Calcium hydroxide suspension and carbon dioxide gas enter from the upper part of the rotating bed, and the suspension is thrown outward through the filling material by centrifugal force in the rotating bed. The filling material is fully cut and dispersed, and the specific surface area is extremely expanded. It reacts rapidly with carbon dioxide to produce extremely fine nano calcium carbonate particles. During the reaction process, the reaction temperature, rate, and pH value can be controlled to obtain products with different crystal forms.
The equipment is a new type of distillation equipment, invented by Zhejiang University of Technology and jointly developed by Hangzhou Keli Chemical Equipment Co., Ltd. In 2004, the high gravity technology was applied to the continuous distillation process in industrial production. The supergravity distillation tower consists of one or more high-speed rotating rotors, and gas-liquid flows through the rotors in a reverse flow manner for contact mass transfer. The 1.2-meter-high supergravity distillation tower is equivalent to a commonly used 15 meter high distillation tower, which is a major breakthrough over traditional plate and packed towers Since 2004, more than 800 sets have been industrialized and applied.
Let me share with you belowSupergravity bedThe operational process
Add calcium oxide and distilled water in a certain proportion into the reactor and stir thoroughly to cool down. When the temperature drops to the specified reaction temperature, maintain a constant temperature and add a certain amount of chemical additives. After stirring for about 20 minutes, introduce carbon dioxide for carbonization reaction. When the reaction proceeds to a viscous state, add a certain amount of aluminum chloride. Continue to introduce carbon dioxide until the endpoint of the reaction, where the pH value of the reaction solution is 6-7. Filter the product, dry and crush it in an oven at 80 ℃ to obtain chain like calcium carbonate.
Add calcium carbonate slurry into the surface treatment kettle, control the treatment temperature with a super constant temperature bath, adjust the stirring rate with a powerful electronic stirrer, add the treatment agent emulsion, and treat for a certain period of time. Filter the processed calcium carbonate slurry while hot, and dry grind the filter cake to obtain active calcium carbonate powder. Adjust the processing dosage to obtain active calcium carbonate powder with different processing dosages.
Add a quantitative amount of chelating agents and dispersants to a certain concentration of lime milk, such as aliphatic (polyhydroxy) carboxylic acids, oxygen-containing carboxylic acids, thiocarboxylic acids, aromatic sulfonic acids, amino acids, etc. If calcium hydroxide is used, the dosage is 0.1-10 g/100 g, and dispersants mainly include aluminum salts, sodium salts, zinc salts, iron salts, magnesium salts, etc. The dosage is 0.05-5 g/100 g. Within the temperature range of room temperature, the volume concentration of carbon dioxide gas is 70%. During carbonization, a bubbling carbonization reaction is carried out under stirring until the pH value at the end of the reaction is 7-8.
The equipment carbonization process technology is advanced, and the product particle size is between 15-30nm, which is the development direction of nanoscale powder inorganic salt production technology in the future.
Introduction to the application of supergravity technology
The supergravity technology can be applied to the production of nano calcium carbonate. The high-speed rotating packing shears the calcium hydroxide solution into fine droplets, filaments, and liquid films. The strong centrifugal force causes the calcium carbonate particles to quickly detach from the calcium hydroxide solution once formed, making it impossible to continue growing. At the same time, the contact area between the calcium hydroxide solution and carbon dioxide gas greatly increases and rapidly updates, greatly improving the reaction rate. The production of nano calcium carbonate products using supergravity technology has a small average particle size and can produce nano calcium carbonate with an average particle size of 15-30 nm; The product has a narrow particle size distribution range; Stable product quality; Fast reaction speed, with a reaction time of only 10% to 20% of traditional processes; The reactor has a small volume; Easy to operate, with stable product quality, greatly reducing production costs. The cost of producing this product using supergravity technology is only 2000 yuan/ton.