Hear our experts discuss how prioritising durability and insulation in refractories reduces energy, which materials should (and should not) be used to bring further sustainable benefits, and how unburnt bricks can reduce temperatures while maintaining properties.
Featuring:
- Adrian Garcia, Business Unit Manager, Industrial Solutions, Lubricants & Energy | IMCD
- Mats Dahmen, Global Business Development Manager, Industrial Solutions | IMCD
Click above to watch our recent panel or keep scrolling to read the questions and answers in the discussion.
Reducing energy seems to be a key to lowering emissions in high energy-intensive industries. So, what can those working with refractories do to prioritise this? Keep reading to uncover more.
Why is the topic of reducing energy so critical now?
Today, industrial production makes up a significant portion of CO₂ emissions. For example, cement production accounts for 7% of emissions and steel production accounts for another 8%.
Energy-intensive industries are now going to be hit quite hard by topics like the carbon tax, and in the past years, rising energy costs, so these industries need to find alternative ways to both drive down their costs and their emissions. Looking specifically at refractories that use upwards of 1800 degrees Celsius to operate, there are a lot of opportunities to try to reduce energy consumption and there needs to be a change to meet a more sustainable way of working
What challenges need to be addressed with refractories to reduce emissions?
Interestingly enough, 90% of the energy used in steel & cement production comes solely from kilns, and all furnaces and kilns used in steel and cement production have small areas that suffer extreme conditions due to high temperatures, chemicals, and liquid infiltration. These conditions force manufacturers to stop production and renew the refractory lining, resulting in a production pause that requires time and materials and uses massive amounts of energy when the repairs are complete, and the production is started back up again. So, what we are looking at here is two things: durability & insulation.
What are successful methods of increasing durability and insulation in refractories?
With durability, the goal is to enhance the performance of the refractory lining to make it last longer. This is achieved in one of three ways:
- Replacing minerals with synthetic products, such as switching tabular alumina from mineral-sourced materials like bauxite, andalusite, or even MgO;
- Decreasing the use of MgO and dolomite basic bricks in both cement and steel production; OR
- Adding non-oxide materials and additives to formulations.
With insulation, for years, insulation refractories were not considered a priority but now many are turning their focus to these materials because of the critical role they can play in cost savings. One approach is the development of customized thermal studies with insulation materials to match. By doing this, we can offer tailor-made products based on equipment, processes, and precise requirements from the final producer. We have seen this bring immense value when it comes to energy reduction in refractories.
Another approach we have seen is the switch from traditional insulation refractories to modern solutions, like ultralightweight castables. This can reduce energy and cut the dissipation of the heat out of kilns. This is particularly successful in lowering energy in steel and cement plants.
Why is this use of these materials important and what benefits can they bring to the production process?
Refractory production, especially with bricks, is a high-energy process that needs to be controlled, or adapted, to reduce the amount of energy required. To rely less on brick, the industry is shifting towards using more monolithic castables that drop the energy consumption in both refractories and end-market production. Because bricks need to be fired or tempered and castables only need to be mixed, castables prove to have impressive results, including the potential to:
- Save time with faster installation
- Require less energy in installations and production
- Save costs with fewer people on site and lower energy requirements
- Have equivalent capabilities and better performance (as compared with brick)
In situations where brick production is still needed, prioritizing unburnt bricks can reduce the amount of energy required. Unburnt bricks require less thermal treatment and can be tempered rather than fired, reducing the temperatures needed in the process.
Furthermore, additives are changing the game. The use of additives:
- Supports brick transportation without the need for firing, reducing tempering from >1200ºC down to 200/300ºC;
- Helps ensure the properties and resistance needed for transportation and installation; and
- Supports the creation of better-unshaped materials that are easier to install and use.
Ultimately, additives make it possible to massively reduce the energy required to produce unburnt bricks, without having to compromise on density, quality, or capabilities.
What needs to be considered when switching to these materials?
The most common mistakes in the use of monolithic materials lie in human error. We see two missteps happen quite often that are detrimental to the approach:
- The first is mixing in water to increase flow capabilities. Oftentimes, excess water is added with the hopes of achieving better flow during castable installation on site. But this approach does not work. Water is the number one enemy in refractories and adding water could ruin the entire process. The use of fluidificant, dispersing agents as additives, is a better alternative.
- The second is the use of the wrong additives to speed up the setting process. Many resolve to use additives to increase the speed of setting but are unaware that the use of the wrong additive could result in adverse effects, such as the setting process occurring too quickly, or not at all. The solution is to rely on additive packaging that focuses on easy-to-work, ‘closed’ formulations to ensure the same performance, no matter the conditions (humidity, ambient temperature, etc).
To avoid performance challenges, it’s best to use easy-to-install materials and consider the big picture of the formulation from the start.
IMCD Industrial Solutions | Sustainable Solutions Program
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