We Grow Fibers in a Calciner

The system discussed above performed well and made a good product, but it was almost certain to cause problems as a manufacturing unit. There had to be a better way. This is when engineers decided to attempt a larger calciner, based on information learned in the laboratory as discussed in Chapter 6. First results were not very encouraging because some severe corrosion problems developed. 

When the research team learned of these corrosion problems, they were recognized as the same problems encountered in laboratory calciners. To avoid corrosion, calciners had to be operated at higher temperatures. It seems as though this is the wrong thing to do, but when they tried higher temperatures, almost in desperation, corrosion subsided to a normal expected rate for most calciner operations. The reasons for this were discussed in Chapter 6. 

This work started in a laboratory calciner as described in Chapter 6. It was demonstrated that [NaCa(P03)3]n fibers could be prepared by spraying a solution of orthophosphates onto a bed of hot crystals. It is an entirely different problem to design a plant capable of preparing millions of pounds per year. Even room-temperature vessels that contain noncorrosive solids or liquids present new problems that lie almost entirely in the realm of engineering. 

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