Covered Cullet Recycling

 

TECHNOLOGY OF THE FUTURE

In the glass industry, all existing types of glass can be conventionally divided into three main types: clear glass, covered glass, and colored glass.

Clear glass is the most popular type of glass used in construction, accounting for about 70% of all glass production. The cullet obtained from the manufacture of products from clear glass is not considered hazardous waste and can be used to make new glass without any prior preparation. Today, most glass manufacturers actively add clear cullet to the glass batch when producing float glass and glass containers.

Covered glass is a clear glass covered depending on the purpose of its use. The most popular covered glass found in every home is the mirror. A thin layer of special paint made of metals such as tin, silver, copper, lead, and others is applied to a sheet of clear glass. Each mirror manufacturer has its own covering formula, which may differ slightly from others, but they are essentially similar. Mirror glass cullet obtained during the manufacture of products may be hazardous if the covering contains dangerous metals. Even if the mirror does not contain hazardous substances, mirror cullet cannot be reused to make clear glass, as impurities will clog the melting equipment and reduce the degree of transparency of the resulting glass. Mirror cullet must undergo mechanical and chemical processing to remove all impurities and obtain transparent glass waste suitable for reuse. In addition to mirrors, there are also back-painted glass, architectural glass, decorative glass, coated glass, energy-saving glass, etc., which can also be classified as covered glass.

Colored glass is glass in which paint is added to the glass mass during production, coloring the glass itself. To obtain clear cullet from such glass, it must be melted and chemically treated to remove the paint. However, this method is not used, as it is not cost-effective.

Leader Glass presents a technology that allows industrial-scale cleaning of covered cullet and obtaining clear cullet suitable for use in the production of new float glass and glass containers

The recycling process involves several stages of processing the covered cullet:

  1. Crushing

    – at the initial stage, the covered cullet needs to be crushed to the desired fraction for further convenience of its transportation and quality impact, as the material’s surface area increases.

  2. Drying and heating

    – at the second stage, the cullet needs to be dried and heated to a certain temperature, which makes it more malleable when it is processed.

  3. Grinding

    – heated and crushed cullet undergoes grinding in a special module. All the coatings are removed and settle as dust.

  4. Screening

    – using various vibration mechanisms and an aspiration system, the dust resulting from grinding is separated from the raw material.

  5. Packaging

    – clear cullet suitable for use is transported to a storage hopper for further loading into a transport vehicle for shipment to production.

covered cullet

As a result of processing 90% of the mass of covered cullet is transformed into clear cullet, which can be added to glass mixtures for the production of float glass and glass containers. The remaining 10% of covered cullet settles as dust, which contains all the covering elements.

This dust can be successfully used in the production of road surfaces and paving materials, as it consists mainly of sand and is well suited for these purposes. For the past three years, we have been actively recycling all types of mirrors and other covered glass and returning clear cullet to the production cycle.

clear cullet