Schermafbeelding 2014-09-30 om 15.17.11

5. Glass as Building Material – Archived

Reduce strip mining and landfills, sequester CO2, get paid for raw materials

The Market

The world uses an estimated 3,200 billion containers of all types to package food and drinks each year – and growing. Nearly everything ends up as waste. Glass is a minor component. Each year some 100 billion glass bottles and jars are produced in highly automated facilities that can crunch out up to one million bottles per day with an average value under half a dollar. In addition to packaging glass, flat glass is used at home and in cars representing 44 million tons. The flat glass market is valued at over $50 billion per year. Glass is a $100 billion market.

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Glass has been produced for 9,000 years and the first bottle appeared 3,500 years ago. Though, recycling bins have only been introduced in the 1970s. Whereas countries like Sweden achieve +90 percent recycling, the US average is under forty, granted that California leads with nearly 80 percent. The UK has a great preference for glass containers using an estimated 8 billion units or 3.6 million tons of which less than one million tons is recycled. The rest finds it way to landfills.

Glass is made out sand rich in silica and could be reused indefinitely. The process of making glass is energy intensive. One ton of virgin glass requires four GigaJoule of energy. Converting used bottles into new containers reduces the carbon emissions with an estimated 17 percent, while avoiding mining. However, recycling is expensive. Members of the European Union and numerous American states impose a deposit which improves the economics. Charging as little as 5 cents per container in America to 25 cents for a liter bottle in Europe creates a secondary market. Unfortunately, the high cost of collection, transportation, and the requirement to separate according to color, has not been offset by taxes and fees. Even major campaigns by consumers and governments does not seem to improve the glass companies’ appetite for more recycled glass. Thus an estimated 65 billion bottles and jars are wasted each year.

The Innovation

Converting bottles back into bottles may seem logical. However asking trees to reprocess leaves back into leaves in the spring does not make sense from a physical, chemical and biological point of view. Just like leaves are converted to soil by microorganisms, fungi and earthworms, the innovation imagined by Andrew Ungerleider and Gay Dillingham in the USA is to convert un-recyclable blends of white, green and brown glass into a glass foam with a wide range of potential applications, except making bottles. It seems that the bottle itself was the bottleneck to the re-use of this natural resource.

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The crushing of used glass into powder, heated up while injecting CO2 creates a foam, lightweight but abrasive, strong and cheap. Since landfills are keen to reduce their load, the recovery of glass on site and the local conversion into glass foam gives way to a new business model: “entrepreneurs get paid to receive raw materials”. The innovation is not limited to cascading of materials whereby the waste of one is an input for the other, the innovation extends to the business model whereby the key ingredients come with cash. In addition, if the factory is located close to (or even on) a landfill, the production facility could benefit from methane gas generated by decomposing organic waste, turning this greenhouse gas into a cheap energy source, cutting costs while further reducing its adverse impact on climate change.

The First Cash Flow

Ungerleider and Dillingham went on to create in 1994 Earthstone. Motivated by their desire to reduce strip mining they turned a known technique into a new business and quickly found a simple market entry in the niche market of physical abrasives. Blocks of recycled glass, with air bubbles and frustules similar to the strong diatom silica, clean a BBQ grill, remove paint, or smoothen fiber boards.

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Since the handling is limited to cutting blocks of glass foam into easy to handle abrasives, and the competition is expensive with a well documented adverse environmental impact, supply stores like Home Depot started carrying the recycled glass-based product. Once the first sales were confirmed, then production increased and improved moving on the experience curve, shifting from a batch to a continuous system, increasingly using local materials at lower cost, turning more competitive.

The Opportunity 

The field of applications is vast. While the US company Pittsburgh Corning, using a similar technique decided to focus on the market of building materials, with their first glass recycling factory in Belgium and a second in the Czech Republic, Ungerleider and Dillingham went on to discover a broad portfolio of applications. Today Earthstone has eleven applications for recycled glass on the market. The latest opportunity is to provide hydroponic agriculture a growth medium, made from glass foam, that can be permanently recycled eliminating a waste stream that strained this agro-industry.

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The Swedish building entrepreneur Åke Mård, located in Sundsvall, Sweden took blocks of glass foam and converted these into pre-fabricated foundations, walls and even roofs for homes. He discovered that glass – filled with tiny air bubbles – serves as a structural building material, not just as an insulation. This innovative construction technique has been approved by the European Union. No water permeates these blocks, no vermin eats its way through the walls, no fungi grow in the basement and the insulation factor outpaces known alternatives in price and performance. Mård realized that recycled glass performs four functions while serving as a physical structure.

The critical mass required to operate a commercially viable oven is estimated at 5 million bottles annually. By 2009, Earthstone processed 5.3 million bottles annually and is profitable. Considering the consumption of 200 glass bottles per family per year, then approximately 25,000 families are needed to make this business viable. The barrier to entry is relatively low. The main cost is energy, which could be supplied by a company with excess heat clustering activities like natural systems do. The creation of these factories generate jobs, while improving the quality of building materials at competitive prices, unleashing entrepreneurship everywhere, reducing the need for transport and mined material.

Photos: SXC, Koljern, Earthstone International

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Schermafbeelding 2014-09-30 om 15.17.11

Glass insulation

Foamglass: from insulation material to sustainable agriculture

by Markus Haastert, Anne Kathrin Kuhlemann, Malte Plewa

Background: What is foamglass?

The construction business is an area of industry which the concept of sustainability has reached relatively late. Nowadays, however, the business of sustainable construction is booming. It is estimated that the profit generated from the green construction business will reach 245 billion US$ by 2016 in the USA alone. This is why new products which promise to make construction greener enter the market regularly. Today we look at one of these products in detail, namely foamglass.

For the production of foamglass, glass is powdered, enriched with carbon and heated up to 900 degrees Celsius, so that is starts to foam. The carbon reacts with the oxygen to carbon dioxide, which is responsible for the bubbles. After is has cooled down slowly, hard boards of foamglass are acquired. Instead of boards, one can also produce granulate by cooling down the hot material very quickly, so that it breaks into pieces.

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The producers of foamglass promote that it can be produced to a large extent with recycled glass from landfills. Waste is transformed to value. Generally, glass is a material which can be molten over and over again to reuse it; however, this is very energy intensive.

Foamglass has several characteristics which make it an impressive insulation material. It does not absorb water, so that it cannot start to mold, and it dries up very quickly. Furthermore, it does not take up or release any compounds to the environment and does not react with chemicals; it is completely inert. Through its stability and resistance to influences from outside, the material does, in contrast to other materials, not lose its insulation capacity over time. The enclosed air particles make it a relatively well-suited insulation material. The heat resistance is impressive, the melting point lies at 650 degrees Celsius. Foamglass granulate is also resistant to very cold temperatures.

Also contaminated material, such as glass from television tubes or mercury containing bulbs can be used for foamglass production. During the melting process, heavy metals are separated from the glass and then delivered to metal processing plants1.

Despite these impressive characteristics, one has to examine the life-cycle of the product in detail to be able to make statement about its potential as a new green construction material.

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Innovation: Insulation and construction with foamglass

Glass is produced from sand, limestone dolomite and feldspar; the production process is extremely energy intensive. The parent materials are heated up to 1600 degrees Celsius and molten. As the energy demand is that high, a study from the German Environmental Agency (UBA) considered it impossible, to produce glass in a sustainable way1. For the production of one kilogram of glass, an energy input of 14 Mega-Joule (MJ) are necessary. Each percent of recycled glass used in the process, reduces the energy consumption by about 0,25 percent. This means that with a recycling-glass content of 75%, as it is the target in foamglass products, one can save 19% of the energy needed. For insulation or construction purposes, aluminum boards are needed for stabilization. The energy input required for the production of a kilogram of aluminum is more than 120 MJ2. The primary energy demand of one cubic meter of foamglass lies between 750 and 1600 Kwh. If one compares the energy used to produce foamglass with the energy needed to produce other insulation materials, such as hemp, the statistics are not really favorable. Also the insulation characteristics of foamglass are not as good as some of its alternatives. Hemp used for insulation has a twice as high heat storing capacity (2300 J/KgK) than foamglass (1110 J/KgK).

The advantage of foamglass is that something which has been considered waste is brought back into the value chain. In Germany, every year about two million ton of glass are collected3. About 85% of this is recycled4. In the USA, however, the statistics look somewhat different; only 28% of the 11,6 tons of glass waste which are produced annually, is recycled5. The demand is therefore enormous. Unfortunately, the two glassfoam producers in the US are using only virgin material in the production process6.

Many airports are being insulated with foamglass, among them the airports of Doha, Dubai, Paris and Düsseldorf.

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Potential: Sustainability and new areas of application

By now, foamglass is not only being used for insulation purposes but also as bearing material in the construction industry. Especially the in granulate form, foamglass is being increasingly used as a base material and in road construction. A study of Norwegian scientist has found out that foamglass-granulate is very well suited for road construction, as it can tolerate heavy weights, strong heat, moisture and cold. The study furthermore shows that the material can be used for the construction of airstrips7. There are already car park levels which are made from this material.

By now it is possible to replace concrete with foamglass. And this is where the actual green potential of the material lies. Instead of concrete, which is a very environmentally unfriendly product due to its high resource demand which often combined with a high quantity of steel, recycled glass can be used. Using foamglass as a material for walls, insulation becomes unnecessary which is often a major factor during construction works. For this, foamglass is combined with aluminum-frames which reduces the time needed for construction drastically. When not only concrete and steel, but also the insulation is replaced by foamglass and additionally a reduction of construction time is achieved, foamglass becomes economically interesting – which is important when is wants to compete with concrete and other materials. Sand resources are being protected and less steel is needed.

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Concrete need 3-4MG energy per Kg during its production, steel about 80 MJ. Using an 80:20 mix, the energy demand is about the same as the one of foamglass in aluminum-frames (both from recycling). The foamglass parts can however be better recycled than concrete, which can only be reused as granulate.

For the construction industry, this product has a great potential. Its sustainability however depends on a few conditions. First of all, it is essential to use old glass in the production of foamglass. The production of virgin glass is very energy intensive and unnecessary as long as not 100% of the actually produced glass is recycled. Furthermore, the heat which used in the production process should stem from waste heat from industrial processes or from landfill gas. If it is possible to reuse the heat which develops as a result of decomposing activities in the landfill in a nearby foamglass factory, transportation distances and energy production can be reduced. At least, renewable energy should be used in the production process, as done by Europe’s biggest producer, Corning Europe NV8

Also the carbon dioxide which is produced on landfills can be used in the production process, in order to reduce the emissions of greenhouse gases. Furthermore it has to be ensured that the foamglass itself reenters the recycling process, once it has been disposed.

Foamglass has the ecological advantage that it is chemically completely inactive. Chemical pollution is often a big problem with insulation materials. Materials such as XPS are often treated with fire protection additives, so that they contain a large amount of toxic components when disposed. As foamglass is fireproof itself, no additives are needed.

Also outside of the construction area, foamglass is being used. Fine grained material is used as a substrate for plants in hydroponic installations. Furthermore, cleaning and polishing devices are made from it. “Sponges” made from foamglass can be used to clean hard surfaces, such as pools, kitchen devices or grills. It is also being sold as an alternative to sand paper1. Many other application areas will most probably follow in the near future, as the speed with which foamglass has entered the market is quite amazing.

The foamglass technology can contribute to transforming millions of tons of waste into a valuable product. However, it has to be made sure, that the process takes place sustainably. As a substitute for traditional construction materials, foamglass has a great potential, as it saves resources and is more stable than alternative materials. As it does not need chemical additives, it can also contribute to a healthier way of living.



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Photos: SXC, Koljern, Wikipedia