Glass melting

Description of glass melting process

Producing glass is a multistage process. It begins with creating its formula that includes molten glass features and appropriate raw materials selection.

On the basis of the formula and after preparing raw materials, batch mixture is being set. The mixture is being intensively mixed in order to achieve its homogeneity.

After a batch mixture is ready and complete, it's being poured into a tank furnace and a glass melting process begins. The target of melting is to convert mixed raw materials that are prepared harmoniously with a certain formula into a liquid melt with an appropriate cleanliness and homogeneity, and to lead to a proper for a product forming temperature. During a melting process, as a result of a high temperature many reactions and physicochemical transformations take place. Their proper course is being controlled by the technologists and determines the achieved quality of the glass. Melting process covers three main stages: batch melting, mass refining (getting rid of the seeds) and cooling down period to achieve a proper for forming products viscosity. Each stage takes place in a different area of the furnace, under the proper temperatures and is tightly controlled by the technologists. Batch mixture is charged from one point of the furnace, next to a wall called "peak". On the same time next to a wall called "frontal" from an end-point, glass mass is being gathered by blowers or forming machines.

Glass melting process begins from batch pouring into a furnace and ends in a moment of transforming all of the components in a glass mass. Batch is being poured onto a previously melted glass mass. Cold batch takes heat from the hot mass that stays below, from the furnace's walls and from the heating flames. As a result of high temperatures presence a train of chemical reactions and physical transformations happens. As a result mass glass comes into being.

Second glass melting stage is a glass mass refining. It rests on eliminating air seeds from the mass. This mainly happens after mass temperature rises, what causes a reduction of its viscosity and surface tension. This helps the seeds to emerge on the surface. Refining process proceeds in 1500°C.

During mass refining process, its flattening happens. Flattening means obtaining equal physicochemical properties on the whole product's surface. Glass mass flattens thanks to air seeds movements, and thermal processes taking place inside of it. This is possible thanks to achieved by high temperature viscosity and lowered surface tension.

Third stage, a cooling- down process lies in progressive and equable lowering a temperature down to achieve a proper for a forming method viscosity. Cooling-down period is an also complicated process. Its incorrect course may cause glass defects formation.

Whole process correctness depends on many factors (raw materials quality, proper batch elements proportion, grading and mixing, proper temperature inside the furnace, etc.). Technologists task is to keep watch and ward on the whole process, in order to achieve as highest glass quality as possible.