GtoG - from gypsum to gypsum

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International HISER Conference on Advances in Recycling and Management of Construction and Demolition Waste

21-23 June 2017, Delft University of Technology, Delft, The Netherlands

234 GtoG - from gypsum to gypsum - a circular economy for the gypsum industry

with the demolition and recycling industries - Life 11 ENV/BE/001392

Christine Marlet

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Eurogypsum, European association of gypsum products manufacturers, rue de la presse

4, 1000, Brussels, Belgium, Phone (+32) 227 11 30; E-mail: info@eurogypsum.org

Introduction

The European Gypsum Industry wishes to promote a circular economy mindset across

Europe by creating a deconstruction culture. Gypsum products can be counted amongst the

very few construction materials where “closed-loop” recycling is possible, i.e. where the

waste is used to make the same product again.

The European Gypsum Industry is conscious of those challenges which are embedded in the

Waste Framework Directive1 and wants to rationalize even more its efforts in conjunction

with the relevant operators in the construction chain to recover construction and demolition

waste.

The European Gypsum Industry wants to enhance the access to natural resources by

developing outstanding C&D waste management that will divert C&D waste from landfill

applying the waste hierarchy (prevent-reuse-recycle-recover, dispose) in accordance with the

life-cycle impact of gypsum products and systems (from extraction until the end-of-life).

Applying dismantling techniques instead of demolishing the building will lead to sorting and

recycling of non-load bearing elements for re-use in the production process. However, as the

waste characterization differs, the production processes of the manufacturers must be

adapted to increase the recycled content in the product. This needs research and

development.

Deconstruction is an essential step in waste recycling feasibility and should become

mandatory if we want to obtain a circular economy. Deconstruction should also be applied in

major renovation and light renovation of buildings. Internal partition in an office can be

dismantled in case of refurbishment of that office, which is not the case currently. Education

of the workforce is here essential to create a dismantling mentality when it is easy to be

implemented.

Objective of GtoG project

The overall aim was to transform the gypsum demolition waste market to achieve higher

recycling rates of gypsum waste, thereby helping to achieve a resource efficient economy.

The market transformation will start happening with the establishment in the project of a

collaborative business model between the demolition/processing/manufacturing & recycling

industries.

Close loop recycling for gypsum products will only happen if:

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Deconstruction techniques are applied systematically for all demolition

and refurbishment projects;

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Sorting of waste is done at source - thereby avoiding mixed waste;

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Processing is carried out according to clear standards;

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235 Therefore, the GtoG project aims to put in place an integrated approach to holistically

manage construction and demolition waste, starting from the major refurbishment/demolition

sites to the reinsertion of the recycled gypsum in the manufacturing process via the

processing of the gypsum waste as a secondary raw material. This integrated approach is

using gypsum products but could be extended, adapted and applied to any other type of

construction material used in light-weight construction.

There are three categories of Gypsum based-waste on origin:

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Production waste (e.g. gypsum products which do not meet specifications and

waste resulting from the manufacturing process).

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Construction waste: waste resulting from construction sites.

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Demolition waste. The last category includes both demolition and refurbishment

waste and is the most complex to address because the waste stream includes other

construction materials (such as plasters, paints & screeds etc.).

Recycled with ease:

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Production waste is generally recycled by the factories and used as raw

material.

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Therefore this measure is waste prevention.

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Construction waste collection and recycling has started and is increasing in

Scandinavia, France, the UK and Benelux. However the re-incorporation rate of the

recycled gypsum in the manufacturing process differs from country to country and

from plant to plant.

Recycled far less demolition waste for the following rasons:

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The buildings are currently crushed and not dismantled, thereby impeding the

sorting of plasterboard before the building is demolished;

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Plasterboard is a relatively new product used in construction after the Second World

War and we are now only beginning to dismantle buildings with plasterboard

linings;

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Gypsum demolition waste tends to be contaminated (screws, vinyl wall paper etc.)

this renders the treatment more complex at higher costs and limits the ability to use

the resulting material.

Outcome of the project

Overall, the project’s implementation:

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Proved that re-incorporation (up to 30%) of recycled gypsum in Type A

plasterboard manufacturing is feasible in practice, even under the adverse conditions

of non-permanent process adjustments. The GtoG 30% target was fully reached in 2

out of the 5 plants. For the examined cases, the net average impact on the total

variable manufacturing cost and energy consumption per m2 of plasterboard was

found to be practically negligible taking into account the uncertainty margin of the

assessment, the current market prices and quality characteristics of recycled gypsum.

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Potential cost-benefits were levelled, mainly due to the requirement of higher

amounts of relatively costly additives. From the cost point of view, process

modification investments may become more attractive in the near future, depending

on raw material prices and national legislations (e.g. gate fee for land-filling).

Stronger economic and environmental benefits can arise in the future, when the

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236 necessary process modifications will be optimised and the recycled material quality

will consistently rely with the quality specifications set by the GtoG project.

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Proved that the reincorporation of recycled gypsum up to 30% does not noticeably

affect the basic performance characteristics of Type A plasterboards; all samples

were found to conform to the EN-520 Standard. GtoG made possible the collection

and analysis of a significant number of recycled material and plasterboard samples

from different origins, which otherwise would not have been feasible.

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Highlighted potential production bottlenecks in terms of recipe modifications (e.g. in

additives) and production process equipment (e.g. storage, feeding conveyors,

recycled gypsum pre-processing, etc.) that may arise when the increased percentage

becomes standard practice in the plasterboard manufacturing. The analysis of the

impacts on individual process parameters and cost elements indicated dependence on

specific feedstock and process characteristics. The outcome of the production trials

allows each manufacturer to develop plans for the relevant and necessary industrial

adaptations, which are costly and require further trials and time.

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Showed that the end-of-waste status is appealing but in practice is today challenging

to achieve at EU level for the recycled gypsum. Indeed, the GtoG project gave the

recyclers and producers the opportunity to have together a round robin test on 20

recycled gypsum samples testing by a third party laboratory, partner to the project. It

is the first time that recyclers and producers have a collaborative approach for the

establishment of quality criteria for the recycled gypsum on a scientific basis. The

gypsum recycling business is growing in France, the UK, Germany, Scandinavia,

Belgium and the Netherlands. New recyclers businesses are emerging. This will give

the Gypsum sector the opportunity to establish further collaborations, also with other

recyclers across Europe, taking advantage of the lessons learnt from the GtoG pilot

tests.

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Showed that the GHG emissions between natural and recycled gypsum are minor.

This minor difference means that decreased emissions derived from gypsum mining

and transport of natural gypsum are almost balanced by the increased emissions

from the pre-processing stage.

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Demonstrated in practice the full engagement of plasterboard manufacturers to

develop recycling practices that will permit higher re-incorporation percentages in

the future. For the first time, the plasterboard manufacturing industry performed

controlled and synchronized production trials in five different plants in four

European counties. By analyzing the entire life cycle, the variations of the impacts

are higher. The emissions from landfill have a decisive contribution to the final

result, due to the methane released from degradation of facing paper.

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237

Figure 2. Gypsum waste hierarchy model

Conclusion

The overall findings and the collective knowledge-experience obtained by the manufacturers

are promising and permit planning of future investigations even at higher re-incorporation

percentages, above the 30% target of the GtoG project.

References

GtoG- from gypsum to gypsum-a circular economy for the gypsum industry with the

demolition and recycling industries -Life 11 ENV/BE/001392