Discovering the unused potential of secondary materials

From the viewpoint of circular economy, a large share of products would still need improvements, particularly as regards the choice of materials and the case of residues. We also need to change our way of thinking and we need more information in order to leverage the unused potential of secondary materials.

Trends affect the product cycle

In its report “Circular by Design”[1], the European Environment Agency[2] examined the impact of product trends on product cycles. The report highlights a positive trend, modular design, which extends the life cycle of products with the help of easy remanufacturing and repairability. Other trends that support circular economy include the services developed around products and shared use, such as making the use of products more efficient.

The development of circular economy is slowed down by complex product design and increased functionality. On the other hand, functional materials may make the use of materials more efficient, but, generally speaking, heterogeneous and complex materials are difficult to reuse and recycle, especially if actions after end-of-life are not designed properly. In other words, increasing complexity and functionality hamper the cycling of materials.

3-D printing, the Internet of Things and the development of markets for recycling are examples of “hot” developing trends, the impacts of which still remain unclear from the viewpoint of circular economy: each one of the above-mentioned trends contains both positive and challenging factors:

  • 3-D printing, or other additive manufacturing technologies, enable local production and improve material efficiency, but, on the other hand, high level of customisation may make the shared use of the products involved more difficult, and the use of many materials in products can negatively impact their recyclability.
  • The Internet of Things (IoT) enables such functions as product tracking and product information management, but may contribute to increasing product complexity and use of critical product materials.
  • The markets for recycling support business models related to recycling, but focusing all resources on recycling may reduce incentives for remanufacture and reuse of products and materials.

Let us not forget the secondary raw materials

In addition to the trends described above, it is good to recognise the potential of secondary materials.

There is no general definition for secondary raw materials, but they typically include waste materials (e.g. mine tailings), side streams (e.g. slag and ashes), processing residues, material removed during product life cycle, and the products and their materials that have reached the end of their life cycle.

Waste-free production is not always possible, since the current production processes generate waste or side products, and the product life cycle is not necessarily very long. The large volume of waste material generated beside our actual product may come as a surprise to many. An example: according to report “Growth within: a circular economy vision for a competitive Europe”[3], we recapture only 5 percent of the raw material value after the first use cycle. Are we really going to forget these lost materials? When discussing sustainability and climate, the focus is often on gaseous air emissions. But what about the solid “emissions”?

Should we change our conception of such “waste material” and, from this point forward, start calling it raw material or material instead of waste?

Should we raise the bar higher? In addition to using secondary materials for such purposes as soil improvement, road construction and filler material, we could aim for high-added value materials and products given an equal status alongside primary materials.

The idea about using and utilising waste materials for functional purposes in particular is good, but there are still major challenges in making that happen, and also concerns such as potential hazardous substances.

The utilisation of secondary materials requires openness, a change in our way of thinking, research and development, scientific competence and pilot production lines. And even more important, contributing factors include enthusiasm, commitment, securing safety sufficient competence and the ability to see the potential of new initiatives in terms of business development both within industry and research.

In addition to idea generation and technical challenges, we are also facing challenges related to ways of thinking, trust, openness, value chain co-operation, markets, legislation and taxation, and getting them solved depends on our common will to do so.

Material science in CloseLoop project

At VTT, we study and develop solutions for circular economy and design strategies for circular products in the CloseLoop[4] project of the Strategic Research Council of the Academy of Finland. We seek, for example, a high-temperature-resistant material, an electroconductive material and a porous ceramic material processed out of secondary raw materials. We aim at finding such solutions utilizing aluminium industry side streams, waste electrical and electronic equipment residues, and other waste materials. All the applications mentioned above and the materials used for them need to have specific technical properties and be functional. We will demonstrate how customised high-added value applications can be produced using secondary materials alongside primary materials, so that, in the future, we could regard these material flows as assets.

Päivi Kivikytö-Reponen VTT

Päivi Kivikytö-Reponen
Senior Scientist
Twitter: @PaiviKivikyto





Raw materials a challenge as climate change worsens

Raw materials are needed in every industrial sector and in everyday life. Many of the current technologies and increase of the middle class are having a fundamental effect on the availability of raw materials.

New raw materials, which differ from those used in the traditional energy sector, are needed for new energy technologies – solar power, wind power and energy storage. Our raw material needs are changing by increased use of electronics, mobile phones and electric cars.

These were among the issues discussed at the Minerals Circular Economy Seminar held in the Satakuntatalo in Helsinki on 8 November 2016. The seminar was part of VTT’s Mineral Economy spearhead programme. The R&D work we have done so far felt worthwhile and received positive feedback, however much work has still to be done. A new VTT Research Highlights publication was released at the event: “Added value from responsible use of raw materials”. It is freely downloadable from the internet:

A product’s environmental impacts are largely determined at the design stage

Resource-efficient product design is not new: its principles were found in design guidelines from the 1930s.


Despite the fact that we know how to take account of reusability and recyclability in theory, products are becoming more and more difficult to recycle in practice, said David Peck (TUDelft, the Netherlands) in his presentation. We are also becoming more dependent on critical raw materials, because almost all functions depend on automatic data transmission and electronics. At the same time, we have become much less able to repair electronic products. This is a situation in which longer-term interruptions in the availability of certain raw materials could lead to serious problems in the basic functions of society.

Many valuable materials are not recycled

Electronics contain many raw materials that are classified as critical or otherwise valuable, some of which are not recycled at all, explained John Bacher in his presentation. The challenge lies in the cost-effective recovery of raw materials that occur in small quantities from heterogeneous and variable material flows. Multiple-stage collection and recycling chains also lead to considerable losses of raw materials, e.g. to dust from material crushing operations.


Several of the presentations referred to the possibility of more efficient processes for the exploitation of raw materials, more efficient recovery, resource-wiser production, and the utilisation of current waste and side streams throughout the value chain. Side streams and currently landfilled waste could be viewed as by-products; achieving the maximum possible increase in their value would enable their more efficient use.

Renewable energy is increasing the need for critical raw materials

The Minerals in Circular Economy Panel (Ilkka Kojo, Outotec; Raimo Lahtinen, GTK; Olli Salmi, EIT Raw Materials Baltic Sea CLC; Erja Turunen, VTT and Maria Wetterstrand) concluded that metals and mineral raw materials will continue to be important in the future. For example, increasing quantities of critical raw materials will be consumed during the generation and storage of renewable energy.


Because renewable energy devices have long lifespans, the stocks of raw materials in use will grow.  We need to use R&D and seize the opportunities offered by digitalisation to find solutions for the sustainable use of raw materials, to avoid eventually having to seek raw materials beyond our own planet.  But all this will not succeed without the support of political decision-makers and consumers.

Mineral Economy spearhead programme is generating technological innovations  

Technological innovations emerging from VTT’s Mineral Economy programme are creating the basis of the circular economy. This meanssmart product design, reuse and remanufacturing, material recycling, alongside a waste-free approach and the added value use of current side streams and waste.

The programme aims to enhance the national and international visibility of VTT’s raw material and material research. Program also contributes to the activities of EIP Raw materials, PROMETIA (the Mineral Processing and Extractive Metallurgy for Mining and Recycling Innovation Association) and EIT Raw Materials and H2020 projects.



Päivi Kivikytö-Reponen, DSc (Technology), Senior Scientist, Manager of the Minerals Economy Programme

At VTT, Päivi Kivikytö-Reponen works on lifecycle solutions, materials from secondary sources, design and wear of industrial materials. She has around 20 years of experience of materials-based product development, research and quality assurance within industry, university and research institute.



Ulla-Maija Mroueh, Principal Scientist

Ulla-Maija Mroueh is a Principal Scientist at VTT. Her research focuses include recycling and waste utilisation concepts, production and consumption chains for mineral raw materials, raw material cycles and management of the environmental impacts of mines. She has over thirty years of experience of both international and Finnish research projects in this area.

Paperculture instead of plasticulture

How was a biodegradable but sufficiently durable paper mulch developed commercially to replace slowly degrading plastic? Senior Scientist Antti Korpela explains the research and development behind the product.

In terms of mulching, Finns are probably most familiar with the black plastic used on strawberry fields. The main purpose of mulching is to prevent weed growth, even out temperature and moisture variations, and prevent erosion. An estimated 90,000 km2 of arable land are covered in plastic mulch each year. Due to the huge benefits, use of this technique is expected to continue spreading.

Plastic film has unpleasant side-effects

But plastic mulch causes a major problem related to its main raw material, polyethylene. Polyethylene is inexpensive and can be used to manufacture a thin and mechanically strong plastic cover. However, it also degrades very slowly on farms. To avoid a deterioration in the quality of arable land and avoid the transfer of plastic waste into the environment, plastic mulch must be carefully removed after use. However, this is laborious, often expensive and not always a complete success. Soil becomes attached to the plastic, making the mulch unsuitable for combustion in incinerators. Recycling, at least on a large scale, has not proven to be economically viable. This means that discarded plastic mulch ends up – expensively – in landfills. Environmental hazards are generated around the world when plastic waste is piled up on the edges of arable land and burned in fields.

Biodegradable plastic mulch, which can be left on the soil after the growing season, has been developed to replace polyethylene. While biodegradable plastics enable farmers to avoid the trouble and expense of collection and disposal after use, they are seldom used due to their high price. They are most commonly used in areas where the costs of collecting and disposing of conventional plastic mulch are very high.

New use for paper machines

VTT and the University of Helsinki’s Department of Agricultural Sciences launched the Agripap project in 2010 , to develop methods of manufacturing paper mulch to replace plastic mulch. Stora Enso, UPM, Walki, Kemira and the agricultural machinery specialist Avagro, also participated in the project, which was part-funded by Tekes.

Paper manufactured from wood fibre is inherently biodegradable and, as estimated at the beginning of the Agipap project, can form a highly competitive alternative to biodegradable plastic mulch in terms of its price per square metre and metre. The global market is very large: around 5–6 million tonnes of paper mulch a year would be needed to cover 90,000 km2.

My colleagues and I familiarised ourselves with plasticulture at the beginning of the Agripap project. Specialists in the physics of paper, the chemistry of papermaking, biodegradation, product safety and environmental accounting were involved in our project. I, at least, made intensive use of a dictionary, as agricultural terms came thick and fast in various texts and presentations. The project steering group also came up with some questions: What is a mulch laying machine and how does it work? What is a raised bed and why is it created? What is a drip hose? Luckily for us, Professor of Agrotechnology Jukka Ahokas was able to explain the terms.

The project included a high number of laboratory studies and field trials. Field trials were conducted on experimental crops in Finland, Turkey and Spain; at the early stages, it became clear that no ordinary paper would serve as mulch.

Only durable and slowly decomposing paper works as mulch

Paper mulch has two critical features: First, the paper has to be durable enough for machine laying onto a field. When being laid, the paper is subject to strong mechanical stress, which it must withstand without tearing. It would be best if paper could be laid using the same laying machines – and just as quickly – as those used for laying plastic.

Picture: Stora Enso

Second, the paper needs to decompose slowly enough to remain intact until the end of the growing season. The edges of the paper, onto which soil is piled to bind the paper cover to the ground, are particularly prone to decomposition. As the edges weaken, the wind can blow the paper mulch off the ground.

The study revealed that making paper which is mechanically strong enough, or that decomposes slowly enough, is easy. But manufacturing paper with both qualities at once is difficult. For example, ordinary sack kraft paper would be suitably strong, but on humid and warm arable land it almost completely decomposes in just 3–4 weeks. Paper made of lignin-rich fibres is much more resistant to decomposition, but producing sufficiently strong paper mulch from such material is difficult.

Stronger, slowly decomposing paper can be made using various chemical additives, but because crops – such as strawberries or lettuce leaves – may be in contact with the material, all raw materials and additives have to be completely safe for humans and the environment. It is recommended that paper mulch meets the strict product safety requirements set for food packaging materials. This rules out many strong additives which would improve the strength of the paper or reduce its rate of decomposition.

Some of the companies involved in the project continued developing the paper after the end of Agripap in 2014. They have explored the practicality of the trial paper mulches on agricultural land at home and abroad. The know-how of institutions such as the MTT (now the Natural Resources Institute Finland – Luke) has been of major assistance to the companies.

For global markets

The development of paper mulch meant learning new things for the companies involved: such as the country and region-specific analysis of farming practices and needs, and sales and distribution planning. The market is global.

A few years ago, I met two product developers from a North American paper manufacturer at the Agricultural Film Conference, where we were gathering information on plasticulture and plastic mulch. They said that paper mulch would be of interest to their company, since there could be big markets for the product, but there was “just too much to learn” about making and selling such paper. This was followed by a deep sigh.

In the spring of 2016, Stora Enso launched a mechanically laid paper mulch for large-scale farming. On my own behalf and that of my colleagues, I would greet this by saying “Well done Stora Enso – what a great achievement!” I hope all that you have learned and your years of investing in paper mulching pay off!

Antti Korpela, Senior Scientist


Picture: Stora Enso