The processing of precious metals is energy intensive. Therefore, it is important to reduce CO2 emissions in production and make the processes more sustainable. To this end, Heraeus Precious Metals has joined forces with the manufacturer to develop an electrically heated chamber furnace that does not require fossil fuels. However, this is not the only project within the scope of the sustainability initiative. The steam generators used in wet chemistry and the thermal oil plant for recycling reformer catalysts are also being converted to green electricity.
Heraeus Precious Metals has set itself the ambitious goal of being carbon neutral by 2025. To achieve this, 100 percent green electricity will be used. In addition, global energy consumption is to be reduced by 20 percent. As early as 2033, the precious metals division of the Heraeus Group wants to completely dispense with fossil fuels. An important component in achieving these goals is a change in technology in individual production processes.
Heraeus Precious Metals analyzed the CO2 emissions of all production facilities at the Hanau site. In addition to the chamber furnaces, the steam generators for wet chemistry and the thermal oil heater for recycling the reformer catalysts had the highest values. All three machine types are now to be converted from natural gas to green electricity. This will lead to the optimization of processes and the reduction of energy consumption. These specific initiatives will also be transferred to other sites. They are part of numerous measures and projects that Heraeus Precious Metals is implementing to achieve the goals it has set and to pursue the topic of sustainability at all levels in the operating company.
The chamber furnaces are used to process precious metal-containing material. While conventional furnaces are operated with natural gas, an electrically heated chamber furnace will be used at Heraeus Precious Metals in the future. Since there was no furnace available on the market that met all the requirements, a project team worked with the manufacturer to develop a new, electrically heated one. One of the biggest challenges was the uniform distribution of energy in the furnace. Using simulations, the designers mimicked and analyzed temperature and flow conditions.
The focus of the development was on optimal energy utilization on the one hand and energy recovery on the other. Until now, energy in the form of heat was lost in this production step. Additional energy even had to be used for cooling. In the new chamber furnace, the hot exhaust air is no longer cooled but used to generate steam - a technical innovation. The recovered energy can also be used for other stages of exhaust air treatment. In total, the new furnace allows around 60 percent of the energy used to be recovered and saves around 570 metric tons of CO2 annually.
Now that the development phase has been completed, the chamber furnace can be built and is scheduled to be ready for operation at the end of 2024. All processes will be powered by electricity from renewable energy sources. The thermal afterburner, which is used to remove pollutants from the exhaust air, is to be converted to non-fossil fuels in the next step.
Annual reduction of around 2,500 tons of CO2
A new thermal oil plant at Heraeus Precious Metals also contributes to more sustainable precious metal processing. The thermal oil plant is part of the alkaline digestion process in which platinum and palladium are extracted from so-called reformer catalysts. For this process, the oil must be heated - previously with gas, in the future with green electricity. This reduces CO2 emissions by around 310 metric tons per year. Heat recovery, the division of a large heating circuit into four individual circuits, and an intelligent control system also reduce energy consumption by around 20 percent.
In addition to chamber furnaces and the thermal oil plant, steam generation is also being converted. Instead of gas-fired boilers, electrically heated steam boilers will be used in the future, which will be supplied with green electricity. The new plant is also much more efficient and consumes less energy. Moreover, the steam generator achieves the highest CO2 savings among the projects at around 1,650 metric tons per year.
All three projects together have a major impact in terms of sustainability: more than one million cubic meters of natural gas can be saved per year, reducing annual CO2 emissions by more than 2,500 tons.