Ball mill ammonium as a substitution for Haber-Bosch process
In a groundbreaking development, South Korean researchers have significantly improved the yield of ammonia production using ball mills, a climate-friendly alternative to the traditional Haber-Bosch process. This innovative method, which utilizes an iron-based catalyst with silicon nitride as a catalyst accelerator, could potentially enable every farmer to produce their own ammonia.
The ball mill technology, initially developed for grinding materials, is now being harnessed for ammonia production. Ball mills are steel containers filled with steel balls that spin rapidly, subjecting materials to impact and shear forces. In this case, the materials are iron catalyst powders mixed with silicon nitride, which enhances the catalyst's activity for ammonia synthesis from nitrogen and hydrogen.
The iron-based catalyst, often promoted by additional elements to improve nitrogen adsorption and dissociation, is the cornerstone of the ammonia synthesis process. Silicon nitride, known for its exceptional hardness, provides resistance to impacts, chemical corrosion, and heat, enabling long-term support of the iron catalyst. As a catalyst accelerator, silicon nitride improves the catalyst properties by enhancing stability, providing novel active sites, or altering the electronic properties of iron catalyst during ball milling, thus boosting ammonia production rates.
The environmental and climate impact of the ball mill technology is nearly zero when powered by green energy. This eco-friendly approach contributes to decarbonization and the circular economy by using recycled solar cell waste in the catalyst accelerator.
Ammonia, the starting material for nitrogen fertilizers essential for securing the world's food supply, liquefies at -33 degrees Celsius, enabling long-distance transportation of hydrogen. With the growing population, the demand for fertilizer and ammonia production will increase. This new method could potentially meet this demand while reducing the environmental footprint.
Moreover, ammonia has a new role as a hydrogen carrier. Hydrogen can be transported from countries with abundant solar and wind power to industrialized nations via ammonia, making it an ideal transporter for the energy carrier of the future.
Although the exact ammonia reaction process with the silicon nitride accelerated catalyst in ball mills is not yet fully detailed, the principle involves feeding iron and silicon nitride powders into the ball mill, milling to intimately mix and physically activate the catalyst components, and using the activated catalyst in ammonia synthesis reactors to produce ammonia from nitrogen and hydrogen gas.
This approach leverages the mechanical energy from the ball mill to enhance catalyst performance, possibly reducing required reaction temperatures or increasing ammonia yield. Silicon nitride's role as an accelerator likely arises from its chemical stability and ability to modify catalyst surface properties.
Researchers at the Max Planck Institute for Coal Research in Mülheim an der Ruhr have also successfully used ball mills to produce ammonia from hydrogen and nitrogen, demonstrating the global potential of this groundbreaking technology.
[1] Liu, J., et al. (2019). Mechanochemical synthesis of iron-based catalysts for ammonia production. Catalysis Today, 346, 104-114. [4] Zhang, Y., et al. (2018). Mechanochemical synthesis of metal nitride catalysts for ammonia synthesis. Catalysis Today, 315, 108-117.
- This climate-friendly ball mill technology, traditionally used for grinding materials, is now being employed for ammonia production, revolutionizing the industry.
- The iron-based catalyst, improves its activity for ammonia synthesis when accompanied by silicon nitride, known for its hardness, chemical resistance, and heat tolerance.
- Silicon nitride accelerates the catalyst by enhancing its stability, providing new active sites, or altering the iron catalyst's electronic properties during milling, leading to increased ammonia production rates.
- The environmental impact of this ball mill technology is minimal, especially when powered by green energy, advancing decarbonization and the circular economy.
- Recycled solar cell waste is even being used in the catalyst accelerator, making the process more eco-friendly.
- Ammonia, a vital component for nitrogen fertilizers, is essential for securing the world's food supply, and its demand will likely increase with population growth.
- This new method could potentially meet this demand while reducing the environmental footprint, as ammonia can liquefy at -33 degrees Celsius, enabling long-distance transportation of hydrogen.
- Ammonia also has a future role as a hydrogen carrier, transporting hydrogen from countries with abundant renewable energy sources to industrialized nations.
- Researchers at the Max Planck Institute for Coal Research in Mülheim an der Ruhr have also demonstrated the global potential of this technology by utilizing ball mills to produce ammonia, contributing to its widespread adoption. (References: [1], [4])
