The global consumption of resources is alarming. Fig. 1 shows the worldwide production of crude steel over the last 50 years for major countries. Since 1970, production has increased by more than 3.1-fold from 601 million tonnes per year (Mta) in 1970 to 1869 Mta in the year 2019. China‘s share in crude steel production increased from 3.0 % to 53.3 % during that time, while the share of Europe (EU28) fell from 32.4 % to 8.5 %. The losers also include the NAFTA states (1970: 22.6 %, 2019: 6.2 %), the CIS states (19.4 % and 5.4 %, respectively) and Japan (15.7 % and 5.3 %, respectively). The share of other countries, which include India, Brazil, Turkey and others, grew from 6.9 % to 21.3 % in the same period of time.
According to the Bureau of International Recycling (BIR), around 630 Mta scrap iron were recycled worldwide in 2019, resulting in a total of 950 Mta of CO2 emissions being saved compared with corresponding crude steel production from iron ore . Thanks to the significant energy savings of around 72 % because of the use of scrap iron instead of iron ore, a massive contribution is made to climate protection. The calculations assume that from the 630 Mta scrap iron, around 37 Mta (6 %) go into crude steel production in blast furnaces (BOF route), while the lion’s share of 523 Mta (83 %) goes into the EF steel process (EF route) and another share of around 70 Mta (11 %) goes to foundries. The recycling of scrap iron is regarded as a flagship example for closing material loops.
But metal recycling is not only about the steel industry. Besides steel, all metals can be used, recycled, remelted and reused any number of times. In metal recycling, a differentiation is made between ferrous (Fe-metals) and non-ferrous metals (NF). Fe metals contain iron as a main component. Non-ferrous metals do not contain any iron (Fe) and consist, for example, of aluminium, copper, lead, zinc, nickel, cobalt, chromium or special and precious metals. Another important step in metal recycling is therefore first a separation of scrap metals into Fe and NF metals. A number of processes is available for this, e.g. magnetic separation. Fe metals exhibit magnetic properties whereas NF metals don’t.
2 Scrap iron
The recycling of scrap iron has a long tradition (Fig. 2). With the increasing global production of crude steel, over the years the recycling rates and the capacities for electric furnace steel (EF) processes have grown. Scrap iron is melted directly there. We can see that crude steel production from the blast furnace process (BOF) as well as from the EF process has increased in recent years (Fig. 3). The share of the EF processes has increased from 25.1 % in 2015 to 29.3 % in 2018. In 2019, the EF percentage fell. This is associated primarily with the high growth in crude steel production in China, which shows with around 21 % a much lower EF share and therefore smaller percentage of scrap iron in the production of crude steel compared to the world averages.
Fig. 4 shows the crude steel production of major production countries for the years 2018 and 2019 with the changes in percent . China was able to increase its crude steel production by 8.3 % to a global share of 53.3 % compared to 51.4 % in 2018. EU28 production fell by -4.9 % to a global share of 8.5 % compared to 9.4 % in 2018. The USA was able to increase its production slightly by 1.4 % to a global share of 4.7 %, has, however, lost 0.1 % points in its global share. Fig. 5 shows how the share of scrap iron in crude steel production has changed for these countries from 2018 to 2019. EU28 lies with a scrap iron share of around 55 % in the midfield. Nevertheless, this share could be increased from 54.2 % to 54.9 % in 2019. Turkey and the USA have the highest shares, while Japan, South Korea and China report the lowest shares.
3 Scrap aluminium
Interesting is a comparison of the figures for the secondary production of aluminium to those for the primary production. Secondary aluminium is produced by remelting scrap aluminium, which consists of new scrap from aluminium production or old scrap from the recycling of used aluminium (Fig. 8). The figures for this vary widely in some cases depending on their source. Here the figures from the International Aluminium Institute (IAI) and from World Aluminium are used (Fig. 9). According to the latest figures from 2018, a total of 32.6 Mta scrap aluminium were utilized, 12.7 Mta of which was new scrap and 19.9 Mta old scrap. In this context, North America and Europe reach high global shares of 21 % and 18 %, respectively, for the scrap aluminium used.
Fig. 11 provides information on the used scrap that has not been collected or unused old scrap. According to IAI, in 2018, from a total of 27.1 Mta of old scrap, 19.9 Mta was recycled as secondary aluminium, 7.2 Mta was unused and sent to landfills or waste incineration. Latin America and Japan have the lowest shares of unused old scrap with just under 20 %, while Europe reaches 21 % and China 23.5 %. North America, with 31 %, is one of the regions with the highest percentage of unused old scrap. This becomes clear from the collection rates for aluminium drinks cans in the USA (Fig. 12). As one can see, the collection rates for aluminium cans have steadily decreased in recent years in the USA and now lie at below 65 %.
Primary production of aluminium is around ten times more energy-intensive than secondary production. For this reason, in many countries, high expectations of further savings are associated with this. In the EU, the aim is to reach full recycling by 2030. For car components and construction products like windows and doors, a collection rate of 90 % has already been achieved, for drink cans it is 75 %. Estimates expect that old scrap aluminium in the EU will increase from 3.6 Mta in 2019 to 6.6 Mta in 2030 and 8.6 Mta in 2050. By 2050, 50 % of the aluminium demand is to be covered by old scrap. Aluminium recycling is set to reduce CO2 emissions by 39 Mta by 2050, which means another reduction of the CO2 emissions from aluminium production by 46 % compared to today.
Norsk Hydro, Europe’s leading aluminium producer with a production output of 2.09 Mta in 2020, has a capacity for old and new scrap aluminium totalling 2.6 Mta. In 2020 around 1.25 Mta scrap aluminium was recycled, including around 85 % new scrap from the company’s own production operations as well as from other companies. For the market, two green products are offered. For the REDUXA product, which is produced in the Karmoy plant (Fig. 3), only hydropower is used, with CO2 emissions of just 4 t CO2/t primary aluminium. For the CIR-CAL75 product, at least 75 % recycled aluminium from old scrap is contained in the finished product. Norsk Hydro wants to increase the quantities of recycled old scrap from 0.09 Mta to 0.6 Mta by 2025.
4 Scrap copper
It becomes interesting if we look at secondary copper production in China for the same period of time (Fig. 16). This increased in the period from 2010 to 2019 from 2.4 Mta to 3.3 Mta . Secondary copper therefore made up 34 % of the refinery production in China in 2019. As shown in Fig. 15, China’s share in the global secondary production has increased from 73.4 % to 81.3 %. In 2019, 2.2 Mta copper was recycled in China itself, 1,49 Mta were imported, of which 1.1 Mta was utilized. For 2020, an increase in the recycling quantities by 1.5 % has been forecast. By 2025, the aim is to recycle a quantity of 4.35 Mta scrap copper in China, including 3.0 Mta from quantities in China and 1.35 Mta from imported scrap.
The Aurubis Group in Hamburg is regarded as the leading supplier and recycler of copper and other non-ferrous metals worldwide. In 2020, the company took over the Metallo Groupo Holding in Belgium (Fig. 18) and could therefore extend its production network of smelting works in Hamburg and Lünen in Germany, Pirdop in Bulgaria as well as Beerse and Olen in Belgium with the recycling of tin, lead, nickel and zinc in addition to copper. In the business year 2019/20, a copper concentrate throughput of 2.38 Mta was generated in the group, following 2.23 Mta in the business year 2018/19 and 2.52 Mta in the business year 2017/18. The quantities of processed scrap copper and blister are on a slight decline and totalled 0.37 Mta in 2019/20, down from 0.44 Mta in the business year 2018/19 and 0.41 Mta in the business year 2017/18.
5 Market prospects
Some of the figures for the recycling of metals are sobering. For this, it is enough to look at the current situation for aluminium and copper. We are a still a long way from a recycling economy. In future, the quantities of metal to be disposed of are set to increase considerably. Estimates assume that, for example, waste electrical and electronic equipment (WEEE) will increase from around 50 Mta at present to around 120 Mta by 2050. At present, in Europe with 12.3 Mta, the second highest quantities of this scrap were sent to Asia for disposal, with 18.2 Mta each year. If this scrap were completely recycled, it would be possible to recover around 0.33 Mta copper and 31 t gold from it. Yet, according to EUROSTAT, the collection rate in the different EU countries ranged for the most part only between 40 and 60 % in 2017.