Drying is a necessary step in the processing of all ceramic products and components, whether it takes place as a separate step or is a preliminary step in the firing process. Ceramics are made from different combinations of materials that can be in slurry form or even more liquid, in the case of slip-cast ware at the start of the fabrication process. This is true of parts ranging from teacups to large refractory molds for melting aluminum to refractory insulation products. All ceramics need to be dried to drive off the large amounts of liquid that are required to make the product.
Problems can appear in many forms if drying is not done uniformly. Cracking due to shrinkage can be a major issue, especially in parts that vary in thickness. All ceramic products also shrink when fired. Drying and pre-firing ceramics help aid in the amount of shrinkage that occurs to the end product. This is very important in thermal processing; if ceramic insulation products are not dried or pre-fired, the resulting shrinkage could cause heat loss issues in a furnace, as well as problems with the end product when it shrinks as heated to the required temperature.