Carbon based fuels played a crucial role in the history and development of minerals processing technologies. As early as 1100BC pig iron was produced, where iron is blended with carbon in the form of charcoal and set alight to create a crude form of useful metal.
Carbon based fuels have historically been the best and often only option to achieve the required process temperatures to convert low grade ore into useful minerals and metals.
During the industrial revolution, carbon based fuel shifted from basic carbon, in the form of charcoal and coal, to more sophisticated and refined energy sources such as bunker fuel oil, refined oil and natural gas. Throughout the decades, these mineral liberation processes have been refined and improved to squeeze every last percentage of energy efficiency from this source of energy.
Throughout the entire industrial revolution however, the fuel has remained unchanged. Carbon based fuel was the only option for the high temperature reactions required for mineral refinement.
Using carbon fuels, the minerals industry has been hampered by the fundamental efficiency limits of a combustion process, where the energy losses through exhaust gas and thermal leakage has defined the limits.
The long carbon chains release energy as they break down in the fire, releasing smaller carbon molecules before finally emitting carbon dioxide as the final stage in the process.
The carbon dioxide emitted from the firing process needs to be exhausted to allow further fuel and oxygen to be introduced, but it carries with it some of the energy from the reaction. Thousands of different technologies have been invented, improved and optimised to minimise these energy losses, but there has never been the possibility of overcoming these fundamental limits of efficiency… until now.
Inspired by our purpose to solve Global Challenges, and a shift in the energy landscape, Calix has spent many years working on the development of a technology ready for the new energy paradigm – electricity.
The decision to develop a calciner that is dedicated to production using electricity as a fuel source has changed the game when it comes to energy efficiency.
Calix’s indirect calciner design was the perfect candidate to take the next step into the age of electricity and benefit from the energy efficiency improvements and increased availability of renewable energy, made feasible thanks to global decarbonisation efforts.
In a recent Calix podcast with James O’Loghlin, Michael Wheatland explained that attempting to convert a direct fired fuel based calciner to use electricity as a fuel would be a bit like trying to bake a cake by dumping all of the ingredients into the oven and expecting a cake to emerge. It creates a huge mess on the heating elements as they are in direct contact with the product, and the resulting cake would be burned in the areas in contact with the elements and undercooked in other areas.
Michael explained that the Calix Technology is the equivalent of inventing a cake tin. It’s a technology that keeps the ingredients clean and separate from the energy source, it enables good heat distribution throughout the process, and results in a high-quality product all whilst keeping your oven clean.
Listen our Podcast: Electrification…the future of the industry.
“The Calix Technology is a bit like a new kind of cake tin. It’s a technology that keeps the ingredients clean and separate from the energy source, and enables good heat distribution throughout the process, resulting in a high quality product while keeping the oven clean.”
Michael Wheatland, Business Development Manager Sustainable Processing
One of the biggest challenges of climate change and elevated levels of CO2 in the atmosphere is the scale of the problem. It seems insurmountable, as global industry has been developed around carbon based fuels for over a century.
While operating a large scale minerals production facility using solely electricity may seem impossible to some today, it is predicted that producing minerals using carbon based fuels in 20 years time will be uncompetitive, thanks to the global push for rapid decarbonisation of industry.
The Calix technology provides a unique solution to the problem of scale up due to the technology being modular. This means the integration of the technology within existing plants is possible, allowing for greater flexibility of production and a greater ability to adjust to energy cost fluctuations, with no detrimental impact on product quality or equipment longevity.
Traditional calcination technologies also have the challenge of needing to remain in operation around the clock, to avoid the possibility of degradation of the hard face refractory – the insulating layer that keeps the heat in the vessel, and protects the vessel’s steel skin.
With the Calix technology, the mineral and process flow never come into contact with the hot face of the refractory. This allows use of a softer and more pliable refractory, more resilient to thermal cycles.
Combining the Calix technology to existing calcining technologies not only allows for energy fluctuations and production rate adjustments, but it could also generate revenue by providing stability to the local electricity grid.
The modular nature of the Calix technology allows the implementation during an expansion of production capacity at a low capital expense, while improving the flexibility of production rates and energy sourcing options as the world changes over the next 50 years.