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Project name:

Non-waste utilisation of copper pyro-metallurgical slag

Status: Idea
Creation date: 12-01-2022

Project objectives:


A Bulgarian research team has developed an innovative technology for non-waste utilisation of copper pyro-metallurgical slag. By means of thermochemical treatment, copper pyro-metallurgical slag with alkaline and / or alkaline earth carbonates is converted into useful materials. The researchers are seeking industrial partners for commercial agreement with technical assistance or research partners for research cooperation agreement.


The Bulgarian organisation is a research institute with more than 40 years of experience in the research and development of specialised materials, coatings and waste recycling technologies. The unit has successfully implemented applied research oriented projects with national and international partners.

The utilisation of industrial waste is one of the most serious environmental problems in industrialised countries. Slag obtained as a residual in pyro-metallurgical copper production is considered as "waste" according to Decision 2000/532 / EC due to lack of a recycling technology. It mainly contains iron silicate, magnetite and silicate glass.

The technology enables after thermochemical treatment with alkali carbonates the waste to be divided into iron and composite silicate phases and to serve as a "precursor" for the preparation of materials with certain properties, e.g., iron oxide pellets and silica gel. Alternatively, after thermochemical treatment with alkaline earth carbonates, it can be transformed into: a hydraulic iron (cement) having a very high iron oxide content; and / or ferro-magnetic glass-ceramics; and / or cladding glass-ceramics and rendered materials with aesthetic appearance.

The technology has several features which are as follows:

  1. Conducting a thermochemical treatment of the copper slag together with alkaline and /or alkaline earth carbonates in a solid phase and obtaining of:

-ornamental glass-ceramic materials for construction; (ferro-) magnetic glass ceramics;

- a hydraulic binder (cement) with a very high iron oxide content; - - and / or a precursor for the production of silicagel (drying) materials together with ferrous oxide pellets applicable in the metallurgy sector;

  1. Performing a thermochemical treatment in a melt and obtaining of render and / or facing tiles with aesthetic appearance.
  2. Thermochemical treatment in hydrothermal environment under specific conditions which are a secret know-how of the research unit and obtaining of: water glass for construction purposes; silica gel (drying material) and ferrous oxide pellets applicable for the metallurgy sector.

The Bulgarian institute offers commercial agreements with technical assistance to industrial partners interested in implementing the technology in their manufacturing process. Technical assistance would include know-how transfer and support with installations. Technical co-operation with any partner needing the Bulgarian researchers’ expertise for their projects is also an option, as well as research cooperation agreements for joint collaborative projects.

Advantages & innovations

The main advantage of the innovative technology is that it converts environmentally hazardous waste - copper pyro-metallurgical slag into valuable glass ceramics (and / or pottery), hydraulically active materials and / or water glass - silica gel with properties useful in various industrial sectors; for instance - architectural and construction purposes. Three novel features are introduced in the developed technology: - application of one of the most progressive forms of induced nucleation - sinter-crystallisation; - sol-gel methods of vitrification and waste utilisation; - crystallisation extraction of the silicate phase of glazed waste in hydrothermal environment.

Stage of development

Under development/lab tested

Contact / source: Enterprise Europe Network (


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