A Belgian limestone producer with locations in Europe, America, Africa, and Asia pulverizes limestone (CaCO3) with a high calcium carbonate content as filling material for the construction industry. Brick manufacturing is a frequent application for CaCO3.
Because clay also consists of silicon dioxide, aluminum oxide, feldspar, and iron oxides, the bricks obtain their typical brown, pink, or red hue, depending on the amount of iron oxide in the clay. If calcium carbonate is added to the mixture, the brick color changes to a yellow or cream hue. With the additional use of coloring agents, one of our mill customers augments the color range to achieve a wide-ranging portfolio of trendy facade bricks.
The limestone producer installed a roller mill and a radial classifier from one of our competitors in 2010. From the outset, the system did not provide the required performance. The system did not grind the material in the required quality and did not reach the promised throughput at any time.
“The mill vibrates too much and is very loud”, as the company already stated to Sales Manager Frank Verreck in 2012 within the course of an initial contact. This contact was furthered at the POWTECH trade fair at the end of 2014.
One year later, our mills and classifier system experts inspected the CaCO3 grinding system and discovered that the installed classifier was unfavorably designed, and the flow routing had several faults. The engineers determined that it was not necessary to redesign the entire system; according to their calculations it was sufficient to exchange the classifier. The pipeline design also had to be adapted and optimized.
As a result, we designed a genuinely revolutionary radial classifier, the DC3000, using the gas/material flow coming from the mill and feeding the rejected coarse material back into the grinding process.
This classifier was designed directly with the largest construction size to-date without prior milling and classifying experiments at our Test Center. Based on detailed calculations, our R&D department determined the housing diameter with three meters.
“This DC3000 was installed one year later and impressed the customer instantly”, as Frank Verreck explains. And that for a good reason, because the customer was provided with fantastic results against very reasonable investment costs.
Pressure loss within the system was minimized and consequently energy requirements reduced. The mill itself now runs with considerably fewer vibrations and far more quietly, resulting in a reduction of the servicing costs because damages are no longer incurred. However, the improved throughput which the customer had to wait for since 2010, is the most important feature. The 90 μm product can now be produced with a 17% higher throughput, for the 50 μm product the throughput was even increased by more than 50%.
