Cooling drum or cooling conveyor – which one is suitable for the metallurgical process?

In metallurgical processes, cooling of bulk material is often a critical step that directly affects the efficiency, safety, and durability of the process. When hot material such as slag, bottom ash, or process dust must be cooled before the next process step or transport, a concrete technology choice is in front: a cooling drum or a cooling conveyor? The right choice depends on the specific characteristics of your process, and there is no one-size-fits-all answer.

This guide will help you make a reasoned choice step by step. We will go through the requirements of your process, assess the suitability of each technology, and finally compare them side by side. If you want to familiarize yourself with cooling solutions now, see our industrial cooling solutions.

Map out the temperature and material flow requirements of your process

Before comparing technologies with each other, you need to thoroughly understand the constraints of your own process. Choosing a cooling technology without a clear understanding of the material properties and process requirements easily leads to an under- or over-sized solution that causes problems during operation.

Gather the following basic information before proceeding:

• Material inlet temperature: How hot does the material have to be before it enters the cooling phase? Is it, for example, a 400 °C paste or a 900 °C bottom ash?
• Target temperature at the outlet: To what temperature must the material be cooled? Does the next process step, storage or transport set a precise upper limit?
• Capacity (t/h): How large is the material mass flow? Is it uniform or variable?
• Material properties Is the material fine-grained or coarse? How fluid is it? Does it tend to liquefy or clog up?
• Space utilization: How much space is available for the cooling device in the layout?

Write down this information before moving on to the next step. The more accurate initial data you have, the more reliable the technology comparison will be. If process data is not available in all respects, conservatively estimate: oversized cooling capacity is usually a better option than under-sized capacity.

Evaluate the suitability of the cooling chamber for your specific application

The cooling chamber is a rotating device where material moves slowly through a rotating cylinder and transfers heat to the coolant via water or air. This technology is particularly suitable for situations where high cooling efficiency and long retention time are required.

Evaluate the suitability of the cooling chamber based on the following criteria:

1. Check the incoming temperature: The cooling chamber is well suited for cooling very hot materials, such as over 600 °C slag or ash. A high inlet temperature is often the cooling chamber’s strength range.
2. Evaluate the structure of the material: Drum cooling works best with coarse or coarser materials. Very fine dust can pose challenges for compaction and dust management.
3. Calculate the required capacity: Cooling drums can be scaled up to very high capacities. If your process requires cooling capacity of more than 10 t/h, a drum is often a competitive option.
4. Pay attention to the layout: The cooling chamber requires space in the longitudinal direction because the cylinder must be long enough to achieve a sufficient retention time. Check whether this space configuration is suitable for your plant layout.

The strength of a cooling chamber lies in its simple mechanical structure and ability to handle hot and abrasive materials for a long time. Maintenance is relatively straightforward because there are few moving parts. Finally, check that your process’s capacity and temperature profile are such that retention-based cooling produces a sufficient end result.

Evaluate the suitability of the cooling carrier for your specific application

A cooling conveyor, such as a refrigerated shuttle or cooling screw, combines material transfer and cooling into a single device. This makes it particularly attractive when space is limited or when material needs to be transported from one location to another during cooling.

Evaluate the suitability of the cooling conveyor based on the following criteria:

1. Check the edge conditions set by the layout: If the process requires both material transfer and cooling, a combination unit reduces the total number of devices required and saves space.
2. Estimate the material's fineness: The cooled collet chucks and cooling screws are also well suited for fine-grained materials such as process dust or aviation ash, as they keep the material in a closed system.
3. Check the inlet temperature in relation to the device's structure: Cooling conveyors are typically effective at temperatures below 600 °C. Very high temperatures may require the use of special structures.
4. Estimate the maintenance needs: Refrigerated conveyors have more moving parts than drum coolers. Ensure that the maintenance program and spare parts availability are designed based on the operating rate of your process.

The clear advantage of a cooling conveyor is versatility: it handles both transport and cooling in one device. This simplifies the process and reduces investment costs in situations where a separate conveyor would otherwise be required. Check whether the cooling conveyor meets the required cooling capacity requirements or whether a larger capacity or a very high inlet temperature require a more efficient solution. You can also get acquainted with our references to see how different cooling solutions have been applied in practical processes.

Make the final choice by comparing technologies side by side

Once you have collected the input data for your process and evaluated the suitability of each technology separately, it's time to compare them side by side and make a decision. Compare the following factors systematically:

• Cooling capacity and capacity: Which technology will achieve the required temperature change at the planned mass flow rate?
• Space utilization: Which one fits better with the layout limitations of your facility?
• Material properties Which technology is better suited to the structure, fineness and cost of the material being processed?
• Investment and operating costs: What is the total cost over the entire lifetime, including maintenance and spare parts costs?
• Continuity of the process: Which technology provides better operational reliability compared to the requirements of your process utilization rate?

If the inlet temperature is very high, the capacity is large, and the material is granular, a cooling drum is often a stronger option. If space is limited, the material is finely divided, or simultaneous transfer and cooling are required in the process, a cooling conveyor offers a more efficient overall solution. In some processes, the best solution is a combination of these technologies, with pre-cooling being done with a drum and final cooling or transfer with a cooling conveyor.

Remember that The sizing of the cooling system directly affects the lifespan of the device, Therefore, the choice should be made carefully based on the actual requirements of the process, not just on the purchase price. Kopar designs and supplies cooling solutions for the most demanding metallurgical processes, always tailored to the customer's needs. Discover our cooling solutions or Contact our experts, So we will go through your process requirements together and help you choose the right technology.