Chapter 18, Problem 1RQ

Outline the steps involved in processing (a) ceramic and (b) glasses.

To determine

Outline the steps involved in processing of ceramics and (b) glasses.

Explanation of Solution

Steps of Ceramics Processing:-

Step #1: Milling & Raw Material Procurement

The raw materials used in the process are milled materials typically found in mining sites that have been reduced from a larger size to a smaller size or even in some cases, it will be pulverized depends upon the end product required.

Step #2: Sizing

Here it is! During this step of the processing sequence, the materials which have gone through the milling, as well as the procurement process should be sized in order to separate the material desirable, from the ones non-usable. By means of controlling the size of the particle, it would result in a proper bonding along with a smooth surface of the finished product.

Step #3: Batching

This part of the process may be called “blending”. It calculates weighing, amounts and an initial blend of the raw materials. To have a material flow consistently into a pub mill hopper, in this process, Vibratory Feeders may be applied if you are having a lighter load capacity and the dusty hazardous environment.

Step #4: Mixing

To get a more physically and chemically homogeneous material before forming, the ceramic powder constituents are combined applying the process of blinging or mixing. Pug mills are the most favored piece of machinery utilized in the concerned step of the process while dealing with dry mixes.

Step #5: Forming

For forming, the materials including pastes, dry powders, or slurries are first consolidated, then molded to form a cohesive body of the desired end product. When it comes to dry forming, to get the desired shape, vibratory compaction may be used.

Step #6: Drying

The formed materials not only hold water but also a binder in its mix. This may lead to shrinkage, distortion, or warping of the product. Usually, convection drying happens to be the most used method where heated air gets circulated around the piece of ceramic which lessens the risk of those imperfections in the finished product.

Step #7: Glazing

This step is added to the process prior to firing. Typically, the glaze consists of oxides that give the product the desired finish look. All the raw materials are grounded in an attrition mill and ball mill. Customers are provided withVibratory Screeners which screened the glaze for giving the mixture a consistency which is not just uniform, but when applied to any of the ceramics, would be even and smooth. The glaze may be applied by dipping or spraying.

Step #8: Firing

The ceramics pass through a controlled heat process where the oxides are consolidated into a dense, cohesive body made up of uniform grain.

To determine

Outline the steps involved in processing of glasses.

Explanation of Solution

Steps involved in processing glasses:-

Step #1: Melting and Refining

In order to make clear glass, the right set of raw materials is required. It comprises of Na2O (sodium oxide) from soda ash, SiO2 (silica sand), MgO (dolomite),CaO (calcium oxide) from limestone/dolomite, and Al2O3 (feldspar). The ingredients get mixed in their right proportions. The entire batch gets flown into a furnace that is heated as much as to 1500 degree Celsius.

Step #2: Float bath

From the furnace, the molten material goes into the float bath comprising of a mirror-like surface created from the molten tin. This material, then, flows into the bath at 1500 degree Celsius. It leaves the bath approximately at 650 degree Celsius. At the exit, its shape looks like a solid ribbon.

Step #3: Coating for reflective glass

 If a reflective glass surface which helps in having the indoors cooler, is produced, then the procedures of coating are followed where either a soft or a hard coat gets applied on the ribbon surface which was cooled at high temperatures.

Step #4: Annealing

For removing the internal stresses built up in the glass, a procedure known as annealing is conducted. The procedure helps the glass ribbon to get through a layer that gets rid of any stresses on the surface of the glass, gradually cooling it to create the final hardened form. Because of it, cutting the glass and shaping it accordingly become easier.

Step #5: Inspecting

Through advanced and acute inspection technology, over 100 million inspections may be conducted throughout the glass manufacturing process for identifying stresses, air bubbles, or grains of sand which refuse to melt. It is vital in quality-proofing the finished form of glass.

Step #6: Cutting to order

Diamond steels are used to trim and cut the glass ribbons into square shapes.