CS233715B2 - Glass stem for colored glass production - Google Patents

Abstract

In addition to basic raw materials and coloring additives, the glass stock for colored glass contains a strongly active reducing agent, which is powdered metallic zinc in an amount of 0.1 to 0.5 kg or/and powdered metallic aluminum in an amount of 0.05 to 0.5 kg per 100 kg of charge.

Description

The invention relates to a glass batch for producing colored glass, in particular cadmium-selenium glass, in an electrode bath furnace.

In the melting of cadmium-selenium glass under industrial conditions, it is used as oxidation reducing agents to achieve the desired color of sulfur, organic carbon compounds and potassium tartrate, as described, for example, in Polish Nowotny: Szkla barwne. Arcade,

1969, p. 151. Also used are other substances, such as zinc or aluminum, cited in the Soviet book of A. A. Appen Chimia barked, Izdatelstvo Chimia, Leningradskoje otdelie,

1970, p. 236.

It is known to melt colored glasses, for example colored CdS or CdS + Se glasses in pans of different shapes or in incandescent furnaces. As an example of known technique is batch material, referenced in the cited Polish publication Nowotny: Szklo barwne composed of 100 kg of silicon dioxide Si0 _2, 10 kg of sodium carbonate KegCO ^, 20 kg of potassium carbonate KgCOp | 4 kg of zinc oxide, 15 kg tetraborate di sodium NagB2O4, 0.8 kg of selenium Se, 0.5 kg of wine lees and 1.4 kg of cadmium sulphide. This results in an intense, canary-yellow color.

Melting of colored CdS or CdS + Se glasses in electrolytic bath furnaces, in particular with molybdenum electrodes from glass batches used up to now in industrial bath furnaces, presents considerable difficulties.

During the melting of cadmium-selenium glasses, constant reduction conditions in the zone of physical and chemical reactions taking place in the bath furnace must be maintained.

Since the ratio of the surface of the glass accessible to the external atmosphere to the molten glass batch and the volume of the glass is large, the surface of the batch coming into contact with the flue gas space is initial. This causes difficulties in trying to achieve the desired color of the glass precisely because of the oxidation reactions taking place on the contact surface.

These disadvantages are well detectable in the case of melting of cadmium-selenium glasses in electrode furnaces where the space above the free surface of the glass and the glass batch is accessible to atmospheric air. Conventional reducing agents hitherto used in glass batches cannot guarantee the desired reaction-oxidation conditions that are necessary to achieve a stable and sufficient intense color of the glass.

In addition, melting of cadmium-selenium glasses in electrode bath furnaces, in particular with molybdenum electrodes, causes severe corrosion of these electrodes. This corrosion of molybdenum electrodes during melting is so great that it leads to technical and operational difficulties. In addition, the products of this corrosion have a detrimental effect on the color of the glass melted in the bath furnace.

It is an object of the invention to avoid the above disadvantages.

The essence of a glass batch for producing colored glass, in particular cadmium-selenium glass in electrode bath furnaces, consisting of basic raw materials and coloring additives such as cadmium compounds, metallic selenium and selenium compounds, and strongly active reducing agents in the form of powdered zinc metal or (a) of powdered aluminum according to the invention, characterized in that, per 100 kg of glass batch, the zinc powder in the amount of 0.1 to 0.5 kg or powdered aluminum in the amount of 0.05 to 0.5 kg.

Indeed, it has been found that, in contrast to the prior art glass batch compositions, the glass batches according to the invention with the stated range of aluminum and / or zinc reduce the corrosion of molybdenum electrodes, so that no corrosion products are affected.

Examples of glass strains according to the invention are given below.

sand 75,00 kg soda 14,00 kg potash 13,00 kg borax , 0.00 kg white zinc 0,80 kg sodium fluorosilicate 1,00 kg cesium sulphide 1,30 kg powdered zinc metal 1,00 kg

Yellow glass was obtained from this batch of glass.

Example 2

sand 75,00 kg soda 14,00 kg potash 13,00 kg borax , 0.00 kg white zinc 8,00 kg cesium sulphide 1.30 kg powdered metal aluminum 0.5 kg

A yellow-colored glass was obtained.

Example 3

sand 75,00 kg soda 15.00 kg potash 12.00 kg borax 8.00 kg metallic selenium 0.10 kg cesium sulphide 0.80 kg powdered zinc metal 2.00 kg

Orange glass was obtained.

Claims (1)

Glass batch for the manufacture of colored glass, in particular cadmium-selenium glass, in an electrode bath furnace consisting of basic raw materials and coloring additives such as cadmium compounds, metallic selenium, selenium compounds, and strongly active reducing agents in the form of metal zinc powder and / or powdered aluminum, characterized in that, per 100 kg of the glass batch, it contains powdered zinc metal in an amount of 0.1 to 0.5 kg and / or powdered aluminum metal in an amount of 0.05 to 0.5 kg.