On the Horizontal Spinden Reactor, the pre-reactor has the job of mixing two liquids, purified water and the concentrated acid solution. Feedback control valves that regulate the flow of either the water or the acid or both can be used to adjust the concentration and mass flow of the acid being used in the product reaction within the horizontal Spinden. The cyclonic action of the pre-reactor ensures that the concentrated acid is well mixed with the water and is at the correct concentration prior to being sprayed into the horizontal reactor. The rotation of the acid solution in the cyclonic chamber causes the solution to spray in all directions as it leaves the pre-reactor into the opening of the horizontal reactor, which eliminates variation of the acid concentration in different regions of the slurry mixture within the Horizontal Spinden’s reaction chamber. Most importantly, by mixing the acid right at the horizontal reactor, the control of the acid mass flow and concentration can be made to respond instantly to variations in the mass flow of the slurry material. The result is a much higher efficiency in the chemical reaction of the horizontal reactor and greater control of the quality of the product material being granulated.
On the Vertical Spinden Reactor, the pre-reactor has the much more important job of initiating the chemical reaction. The calcium or phosphate slurry is connected directly to the vertical flange of the pre-reactor. The concentrated acid is injected tangentially at the top of the cyclonic reaction chamber. The reaction of the acid with the slurry produces heat and carbon dioxide gas, which rapidly increase the pressure within the reaction chamber. This further facilitates the chemical reaction and helping to initiate the chemical reaction for the product components entering the pre-reactor.
