摘要:
A method and apparatus are disclosed for continuously drying, preferably with agglomeration and/or coating and sizing, and separating a solid product from a liquid feed material, especially bauxite slurry which passes through a very sticky phase during drying, without significant encrustation of the equipment used. The method comprises: spraying a liquid bearing solid material upwardly into a drying zone, feeding a drying gas into the drying zone from below The spraying liquid in substantially parallel flow, removing the mixture of the drying gas and entrained dried particles from the drying zone, separating the entrained dried particles from their mixture with the drying gas, returning the separated dried particles to the drying zone, and collecting the dried particles, characterized by arranging for the formation of a slower moving boundary layer within the feeding of the drying gas, through which boundary layer dried particles are allowed lo fall under gravity to be collected, and by collecting the dried particles continuously from below the spraying liquid.
摘要:
Disclosed is a process for the elimination of volatile, foul-smelling organic compounds which are liberated in a gas suspension calciner process utilized to manufacture alumina. The process comprises recirculating captured alumina dust on which undesirable volatile organic compounds are adsorbed to a location in the manufacturing process (1) at or upstream (based on the path of the conveying gases) from the gas suspension calciner and (2) which is operating at a temperature of about 700 ° C. or higher. The adsorbed organic compounds are stripped off the alumina dust and are subsequently directed by process air into the gas suspension calciner furnace which is operating above 1000 ° C. under oxidizing conditions. Under such conditions the organic compounds are oxidized to H2O vapor and CO2. It is a preferred feature that the volatilized organic compounds are adsorbed on the alumina dust in a baghouse.
摘要翻译:公开了一种消除在用于制造氧化铝的气体悬浮煅烧法中释放的挥发性,臭味有机化合物的方法。 该方法包括将不希望的挥发性有机化合物再循环到其上,在制造过程(1)中或在其上游(基于输送气体的路径)从气体悬浮煅烧器吸附不期望的挥发性有机化合物的位置和(2) 在约700℃或更高的温度下。 将吸附的有机化合物从氧化铝粉末中剥离出来,随后通过工艺空气引导到在氧化条件下运行在1000℃以上的气体悬浮煅烧炉中。 在这种条件下,有机化合物被氧化成H 2 O 2蒸气和CO 2。 优选的特征是挥发的有机化合物被吸附在袋式除尘器中的氧化铝粉尘上。
摘要:
This invention relates to a method for the production of anhydrous alumina having a desired .alpha.-conversion from alumina trihydrate.This method is directed to production of anhydrous alumina having a desired .alpha.-conversion from alumina trihydrate in which water is removed in a precalcining zone wherein the alumina trihydrate is heated to a temperature below 450.degree. C. Then, the precalcined dehydrated alumina is recrystallized to .alpha.-alumina in a reaction chamber by directing an oxygen containing gas to the reaction chamber, mixing and suspending the precalcined alumina and fuel in the oxygen containing gas and feeding the mixture to a combustion zone, followed by exothermal recrystallization of the alumina which is initiated by rapidly heating the precalcined alumina by burning the fuel in the oxygen containing gas in the hot combustion zone and withdrawing the recrystallized alumina from the top of the reaction chamber suspended in a combustion gas stream. The recrystallized alumina is then separated from the gas stream and cooled to produce anhydrous alumina having the desired content of .alpha.-conversion.