Reducing Carbon Emissions Through Accurate Moisture Measurement During Clay Brick Production

The UK has a target to achieve net zero emissions by 2050 and the brick industry is a key stakeholder when it comes to creating a roadmap to achieve this target.

As part of this roadmap, the brick industry has set itself a number of key objectives in areas such as using water as efficiently as possible, improving energy efficiency, and reducing the amount of waste generated.

Moisture Levels

A key component in achieving these objectives is monitoring and controlling the moisture levels in the clay throughout the production process.

Clay is a natural material, the moisture present can depend greatly on where the clay is from, how it is stored, the different particle size, and the humidity in the atmosphere. The moisture level can even vary in different batches of clay from exactly the same source.

The level of moisture present in the clay is extremely important as it ultimately affects the quality of the resulting brick, too much and the brick will fall apart or sag, too little and the brick will simply crumble, but with the correct level of moisture, it will be possible to get good, dense compaction of the clay, the brick will release easily from the mould and the brick will be fit for purpose.

To get this balance correct, it is necessary to make adjustments during the brick production process, either adding more water if the clay is too dry or adjusting the drying time necessary to remove any excess water. If the moisture level is not managed correctly, brick manufacturers are at risk of using more water and energy than necessary and producing bricks that aren’t fit for purpose, generating more waste.

In order to control these adjustments accurately, it is absolutely vital to be able to measure and monitor the moisture levels precisely. If the moisture levels are known, then brick manufacturers can calculate and adjust the amount of fuel and drying time required, reduce the energy used and the number of rejects produced, therefore optimising production levels and cost savings.

Moisture Gauges

The most effective way to measure and monitor the moisture levels is by implementing non-contact, near infrared (NIR) moisture gauges which, working on proven optical filter technology, can continuously measure the clay moisture with total precision to an accuracy of ±0.3%.

Infrared light at a specific wavelength is absorbed by water molecules, the gauge projects pulses of light at this wavelength and other reference wavelengths not absorbed by moisture, onto the product. Some of this light is absorbed and the rest is scattered/reflected. The gauge light collecting optics focus the reflected intensities onto a detection system, which compares the amount of moisture absorption with the reference wavelengths, providing a measurement.

Algorithms convert the infrared signals into an output that is proportional to moisture content, and calibration is carried out using the normal slope and intercept (Span and Trim) controls to ensure that the results are consistent with those provided by the customer’s primary reference method.

The measurement speed is exceptionally fast and delivers a continuous moisture measurement that can be output via a 4-20 mA or various Ethernet industrial protocols to the process PLC or SCADA system.

Brick Manufacturers

Brick manufacturers Forterra, Wienerberger, Ibstock Brick, and Michelmersh have already implemented non-contact NIR moisture gauges supplied by LIMAB UK.

We found that we were actually losing a lot of money due to not having the correct moisture content in our bricks, so back in January 2019, we decided to look into implementing some non-contact NIR moisture gauges to enable us to monitor this more effectively. I am very happy with the PrediktIR gauges and having the ability to constantly monitor the moisture content has massively improved our quality control processes.

Scott Bamford – Technical Manager at Ibstock Brick

I knew that some of the other Wienerberger sites had already purchased some NDC PrediktIR moisture gauges and I had heard that they were really improving the production processes and quality control procedures. After discussions with a NDC Product Specialist, we went ahead and purchased four NDC PrediktIR gauges. The gauges have really helped us to monitor and have greater control of our water input system and we are already getting some really useful data.

Philip Smallridge – Process Improvement and Quality Control at Wienerberger

If you would like to find out how an NIR moisture gauge could help your company to optimise production levels and cost savings whilst reducing waste production and carbon emissions then please do get in touch.