What Is A Carbon Analyzer And Why Is It Important For Converter Analysis?

To accurately determine the precise amount of platinum, palladium, and rhodium in spent catalytic converters, toll-refiners use X-ray Fluorescence (XRF) benchtop and Inductive Coupled Plasma (ICP) devices. But sometimes there can be a snag in the process: carbon content in  the catalyst material can disrupt the analysis and overall results.

That’s why PMR uses a carbon analyzer—also sometimes called a carbon detector—which measures the amount of carbon in your catalyst material. However, we understand that just telling you we analyze carbon content doesn’t help you understand how we do it. So if you’re ready to get informed, stay tuned as our laboratory manager, Alex Benoit, gives us a closer look at the carbon analyzer.

Why is Carbon Present in Catalyst Material?

Catalytic converters have a ceramic substrate coated in platinum, palladium, and rhodium. These metals serve as a catalyst that transforms harmful pollutants into less toxic gasses. However, they also have a certain amount of carbon in the ceramic substrate, which has two primary functions.

First, carbon improves the structural stability and strength of the substrate. This is important because it has to endure the harsh conditions of the exhaust system, including high temperatures and vibrations. The carbon helps to reinforce the ceramic and prevent it from cracking or breaking.

Secondly, carbon enhances the effectiveness of the catalyst. That's because the performance of a catalytic converter depends on the surface area available for chemical reactions. The catalyst materials are coated onto the ceramic substrate to provide a large surface area for exhaust gasses to interact with the catalyst. The presence of carbon in the ceramic substrate helps create a greater surface area, which promotes the conversion of harmful pollutants into less harmful substances

The presence of carbon in converters serves structural and functional purposes. It contributes to the overall performance and durability of the device. That's why processors need to measure how much carbon is in your catalyst material.

How Is Carbon Content Measured?

Carbon content is detected through the combustion method. In the carbon analyzer, a magnetic field is produced by a coil, which heats the sample through induction. Pure oxygen is added to feed the combustion reaction, which transforms the carbon into carbon monoxide. Then the carbon monoxide oxidizes into carbon dioxide (CO2).

Once the reaction is complete, the carbon dioxide enters an infrared detector. Because CO2 has a strong absorption in the infrared, it’s easy to quantify it using its signal, which is traced with a graphic that tracks the content throughout the combustion process. The area under the curve of the signal is where we calculate the concentration of carbon content.

Machine Calibration & Quality Control

Processors should ensure the precision of carbon results with proper calibration and maintenance. Leak verification is where laboratory employees should begin because CO2 leakage from the instrument will undervalue your carbon content. That’s why it’s important to run leak verification before using the machine.

Processors should perform quality control checks on the carbon analyzer before and after each sequence. For example, if there are 4 samples for 1 lot, Benoit and his team conduct quality control checks before the first sample and after the last.

Complete calibration is necessary every 6 months. Benoit also suggests doing a performance qualification test to ensure that the instrument is up to industry standard.

At PMR, we use the Leco Carbon Analyzer, an industry-leading device in the organic and inorganic sciences. This state-of-the-art instrument allows us to analyze carbon content quickly and precisely. Doing so prevents unwanted carbon content from skewing your assay, helping you hedge your metals accurately.

Precise Assay Results Matter

In this industry, precision is a competitive edge. That’s why carbon detection in your assay is critical. You’ll get the most precise results possible, helping you hedge your metals accordingly and maximize your returns.

At PMR, we understand that your assay results help you hedge your metals accurately. For this reason, we optimize the accuracy of your assay by using a carbon detector, ensuring that your results aren’t affected by any unwanted carbon content.

For more information, visit PMR’s Resource Center.