Coprocessing

The cement kilns, due to their high temperatures (up to 2,000 ° C), represent a widely diffused and recognized adequate and safe alternative for the thermal destruction of industrial waste and environmental liabilities.

In this alternative, known as coprocessing, the industry takes advantage of waste as fuel substitutes or raw material. This process, in addition to providing an environmentally adequate destination for tailings from other activities, allows, even partially, to reduce the use of traditional non-renewable fuels, such as petroleum coke, fuel oil and coal.

The waste coprocessing is able to destroy a wide range of industrial wastes in an environmentally correct and safe way, of which the main ones are:

• Used tires

• Oils, greases, paints and solvents

• Plastics and Rubbers

• Waste wood and sawdust, paper and cardboard

• Effluent treatment plant sludge

• Contaminated soil

• Depleted grains and animal carcasses

Coprocessing offers several advantages:

• Definitive disposal, in an environmentally correct and safe manner, of various types of environmental waste and liabilities;

• Replacement of non-renewable fossil fuels with alternative fuels;

• Preservation of deposits by incorporating the inorganic compounds into the clinker structure, replacing the raw material part, without any alteration of the characteristics and quality of the product;

• Contribution to public health, for example, in combating the outbreaks of dengue with the destruction of waste tires.

• Reduction of greenhouse gas emissions through the use of alternative fuels with lower CO2 emissions.

 

The burning of waste in cement kilns has been widely explored in Europe, the United States and Japan since the 1970s. Currently, this alternative fuel already accounts for about 35% of total energy consumption in the European Union.

In Brazil, the activity began in the 1990s, in the South and Southeast regions, and was regulated by the environmental agencies of RS, PR, SP and MG and, at the national level, by Resolution CONAMA 264/99.

Coprocessing has increased considerably since the 2000s in Brazil, but is still below developed countries, accounting for approximately 9% of the matrix of fuels used in the cement industry.

Today, the activity is spread in 18 states of the Federation and of the 57 integrated plants that have rotary kilns for the production of clinker, 38 are licensed for waste coprocessing.

In 2015, 1.07 million tons of waste were co-processed by the national cement industry. However, the sector has a total destruction potential of approximately 2.5 million tonnes, which represents an important alternative for reducing environmental liabilities resulting from increasing waste generation and for mitigating greenhouse gases.