Unsustainable industrial practices contribute to climate change, increase scarcity of raw materials and further environmental deterioration – negatively affecting the wellbeing of our world and its people. There is, therefore, an urgent need to reorganise the current economic system of value addition, from a linear process into a restorative and regenerative one – a system in which materials circulate at their highest value for as long as possible, minimising the environmental impacts of production and consumption. The technologies and processes used along the entire life cycle of raw materials – from extraction, to manufacturing and waste management (including reusing, recycling, and recovery), can help us transform the ‘take, make, dispose’ model into that of a more sustainable circular economy.
Industrial development is an engine for economic growth and prosperity. Around one fifth of all jobs worldwide are within the industrial sector, with manufacturing also accounting for a significant share of GDP in economies around the world – including both developing countries (in 2017, industry was responsible for 25% of Equatorial Guinea’s GDP) and developed (accounting for 21% of Germany’s GDP).
Industry also adds value to other sectors – through the purchasing of services and materials from providers, as well as stimulating other economic activity through its outputs. As demand for manufacturing products grows, investments and innovations elsewhere in the supply chain are stimulated . In fact, added value from global manufacturing more than doubled between 1990 and 2016, with the greatest increase being in emerging industrial economies.
At the same time, manufacturing accounts for nearly a third of the world’s energy consumption and 36% of CO2 emissions – contributing hugely to climate change. In order to continue to achieve socio-economic development, while also minimising negative environmental impacts associated with industry, a more sustainable approach to both production and consumption is needed. Indeed, an ethos of ‘doing more, better, with less’ is key to fulfilling the UN’s SDGs.
Finite, non-renewable resources have increased threefold from 1970 to 2010. This growth is attributable to the rapid industrialisation of emerging economies, alongside continuing high levels of consumption in developed countries. To become sustainable, we need to look beyond the ‘take, make, dispose’ model, and increase its focus on a circular economy approach.
A key feature of the circular economy is a focus on restoration of end-of-life materials by returning biological materials to the earth and/or returning non-biological materials to the economy. Unlike other materials, metals and their alloys are highly durable, anticorrosive and infinitely recyclable meaning they can be re-used. Even if contaminated, they can often be cycled into a lower-value product or application.
Another area where manufacturing can improve is in reducing material waste. Traditional manufacturing methods are based on ‘subtractive’ processes: an inefficient and wasteful process where unwanted material is removed from a larger block – such as carving a piece of wood, cutting shapes from pre-formed sheets of metal, or chiselling away at a lump of granite. A greater use of alternative ‘additive manufacturing’ methods, such as 3D printing, would be hugely beneficial in reducing this waste.
Waste is also rife at the consumer end of the production cycle. For example, in the EU alone, each person consumes an annual average 16 tonnes of raw materials – six tonnes of which become waste, with half being landfilled and never used again.
The traditional linear path of industrial development has to be replaced with circular approaches that prioritise resource efficiency, waste minimisation, and value maximisation throughout the product lifecycle – including raw materials extraction, processing, product design, production, consumption, and waste management. Fortunately, modern technologies allow us to reduce, re-use, recover, and recycle non-renewable raw materials – thus saving valuable primary resources and furthering sustainability.
Sustainable industrialisation through technology
A sustainable industrial future requires innovative solutions which enable the de-coupling of economic growth from material consumption. This requires technologies for efficient production and the lean management of resources – as well as the re-use, recovery and recycling of waste. Metals and minerals are indispensable in the manufacture and functioning of all of these technologies.
3D printing (3DP) enables flexible, efficient, sustainable manufacturing – adding materials one layer at a time, with near zero waste. It also enables swifter response to demand and more localised manufacturing, relies on a simple supply chain, and requires fewer raw materials than traditional manufacturing methods. 3DP also makes it possible to produce single parts, which may be easily combined together or disassembled in order to be repaired, replaced or upgraded. This supports the circular economy transition, as if any damage occurs to a product, it does not have to be landfilled as waste. It is estimated that additive printing could reduce manufacturing costs by USD 170 to 593 billion, energy use by 2.54 to 9.30 exajoules (EJ) and CO2 emissions by 130.5 to 525.5 metric tonnes by 2025. 3D printers are built from a variety of metals and minerals, including aluminium, iron, copper, nickel, chromium, tin, zinc, bauxite and sulphur.
A waste autoclave is a chamber in which pressurised steam is used to decontaminate waste. They are used in nearly every industrial sector, including aerospace, composites manufacturing, or metal heat treating. The state-of-the-art autoclave chambers are manufactured using stainless steel, or nickel-clad. Once waste is put inside the autoclave and the chamber is closed, all air is removed, by a vacuum pump or by pumping in steam. In the next step, high pressured steam is injected into the chamber to raise the internal temperature, a timer is started and the process begins. After sterilisation, during which microorganisms are killed, the autoclave chamber is exhausted of pressure and steam, so that it can be safely opened for cooling and drying. Waste can then be taken out and circulated back into the economy as a resource.
Materials recovery facilities
Materials recovery facilities (MRFs) – also known as materials recycling facilities – play an important role in recovering, re-using and recycling raw materials. Waste delivered to the facility is sorted into different types of materials, including plastics, cardboard, paper, or metal. MRFs include a tipping floor, a drum feeder, units for separation operations, storage areas and transporting equipment.
Incoming material is dumped onto a tipping floor, usually made of concrete or a combination of recycled iron shavings and concrete. Concrete is made of air, water, cements (made of calcium, silicon, aluminium, iron and other ingredients), supplementary cementing materials (eg fly ash, slag cement, silica fume), aggregates (eg sand, gravel, crushed stone) and chemical admixtures. Waste is then dropped into a large steel bin (known as a drum feeder). In the next step, cardboard is removed by a screen using rotating shafts with discs (usually made of stainless steel, aluminium, or brass). Non-fibre elements are sorted using automated optical processes with the use of cameras and lasers, while a magnet (produced from an alloy of various metals, including iron, nickel, zinc, cobalt, and others) removes steel cans, and an eddy current separator (including rare earth magnets) removes the aluminium cans and non-ferrous metals. Glass bottles are shattered by steel discs, while plastics are separated by an optical or manual sorter.
Composting is another way to manage waste. Industrial composting methods include aerated static pile composting, high fibre composting, in-vessel composting, mechanical biological treatment and windrow composting. In general, composting means a biological decomposition of organic matter by fungi, bacteria, insects, worms and other organisms. It is a relatively quick, safe, clean and natural process. Composted output can be used in many different ways, including agriculture, brownfield sites or even energy generation. Some composting methods, such as in-vessel composting, rely on equipment which could not be built without metals and minerals. In-vessel composting uses an environment-controlled enclosed environment – like a drum, silo, container or concrete-lined trench – into which organic materials are fed prior to turning or mixing. The size of the vessel can vary in size and capacity, but is built mainly of steel and aluminium.