Abstract A process is disclosed for preparing simple, mixed or substituted mild ferrites or barium titanate starting from a slurry containing said constituents and if desired one or more binders and/or dispersing agents, characterized in that, (a) the slurry is dried and granulated by using the hot gases flowing out of stage (b), supplemented if desired by hot gases obtained separately, and which have inlet temperatures of from 400* to 800* C, with the granules having an average size of 150-300 microns; (b) the granules obtained in stage (a) are calcined at temperatures between 700* and 1100* C in the case of ferrites, or between 1150* and 1200* C in the case of barium titanate, in a fluid bed reactor; for 0.5-4 hours, by injecting into the reactor itself a gas or an oxidizing, reducing or inert gaseous mixture, depending on the desired product, and heated either inside or outside the reactor itself; and (c) the product thus obtained is cooled down in a controlled manner and is then ground (preferably in a ball mill by the wet method) to obtain the desired final product.
A CONTINUOUS PROCESS FOR PREPARING BARIUM TITANATE CHARACTERIZED IN THAT: A. A SLURRY CONTAINING TITANIUM DIOXIDE AND A BARIUM SOURCE SLECTED FROM THE GROUP CONSISTING OF BARIUM CARBONATE AND BARIUM OXIDE IS DRIED AND GRANULATED BY USING THE HOT GASES FLOWING OUT OF STEP (B), SUPPLEMENTED BY HOT GASES OBTAINED SEPARATELY, AND WHICH HAVE INLET TEMPERATURES OF FROM 400* TO 800*C, THUS OBTAINING GRANULES WITH AN AVERAGE SIZE OF 150-300 MICRONS, B. THE GRANULES OBTAINED IN STEP (A) ARE CALCINED AT TEMPERATURES BETWEEN 1150* AND 1200*C IN A FLUID BED REACTOR FOR 0.5-4 HOURS, BY INJECTING INTO THE REACTOR ITSELF AN OXIDIZING OR INERT GAS HEATED ETHER INSIDE OR OUTSIDE THE REACTOR ITSELF, AND C. THE PRODUCT THUS OBTAINED IS COOLED DOWN IN A CONTROLED MEANNER AND IS THEN GROUND TO OBTAIN THE DESIRED FINAL PRODUCT.
Claim 2
Dependent Claim
136 words
A CONTINUOUS PROCESS FOR PREPARING BARIUM TITANATE CHARACTERIZED IN THAT: A. A SLURRY CONTAINING TITANIUM DIOXIDE AND A BARIUM SOURCE SLECTED FROM THE GROUP CONSISTING OF BARIUM CARBONATE AND BARIUM OXIDE IS DRIED AND GRANULATED BY USING THE HOT GASES FLOWING OUT OF STEP (B), SUPPLEMENTED BY HOT GASES OBTAINED SEPARATELY, AND WHICH HAVE INLET TEMPERATURES OF FROM 400* TO 800*C, THUS OBTAINING GRANULES WITH AN AVERAGE SIZE OF 150-300 MICRONS, B. THE GRANULES OBTAINED IN STEP (A) ARE CALCINED AT TEMPERATURES BETWEEN 1150* AND 1200*C IN A FLUID BED REACTOR FOR 0.5-4 HOURS, BY INJECTING INTO THE REACTOR ITSELF AN OXIDIZING OR INERT GAS HEATED ETHER INSIDE OR OUTSIDE THE REACTOR ITSELF, AND C. THE PRODUCT THUS OBTAINED IS COOLED DOWN IN A CONTROLED MEANNER AND IS THEN GROUND TO OBTAIN THE DESIRED FINAL PRODUCT.
Claim 3
Dependent Claim
23 words
A process as defined in claim 1, wherein the grinding step (c) is carried out in a ball mill in the wet way.