What Would You Do If The Life Of Your Quarry Was Being Cut Short Unnecessarily?

Cement manufacturing begins at the mine, where raw materials like limestone and other rocks and minerals are acquired.  One of our customers was faced with a situation that was jeopardizing the life of the quarry, and ultimately the business. What could they do to protect their investment? Cement is formed by heating a mixture of limestone (calcium carbonate) with other materials, such as clay, to form a clinker, then pulverizing the clinker into powder.  Magnesium oxide (MgO) is produced by the calcination of magnesium carbonate or magnesium hydroxide as well as by the treatment of magnesium chloride with lime followed by heat.  This means that the cement manufacturer risked an unknown in one of his ingredients.  How much MgO would be in the raw material vs added after the materials are heated. Since the heterogeneity of MgO concentrations throughout the limestone quarry is unknown, and with no way of controlling the MgO content at the quarry, the plant would often run below the target percentage and thus waste limestone, which could otherwise have been used in the cement manufacturing process.  This was effectively reducing the life of the quarry, as well as wasting limestone. So the question became:  how can they make the perfect cement most efficiently, while not wasting one of the crucial ingredients in their recipe? The answer was to add a cross-belt elemental cement analyzer for achieving consistent stockpile and raw mix chemistry during process control. The company believed that if it was able to monitor the limestone being sent to the plant and acquire real-time, minute-by-minute results, they would no longer waste the raw materials. The analyzer tracks the chemistry of the stockpile compared to the target chemistry and determines the preferred proportions of the source raw materials. In addition, a primary determinant of kiln efficiency is the chemical uniformity of kiln feed. Kiln feed uniformity is in turn derived from the precise control of raw mix.  The system provides the precise control needed to minimize raw mix variability while at the same time minimizing raw material costs and satisfying multiple quality control targets. Now the cement producer can achieve consistent stockpiles with minimal variations within and between piles. After installing the analyzer – which gives the option of using either an electronic neutron generator or californium (Cf-252) as the source of the neutrons — the company saw that the MgO in the final clinker increased from 2.07% to 3.03%.  The addition of an online analyzer allowed the plant to increase the MgO of the limestone and thus significantly reduce costs as well as lengthen the active quarry reserves.  That smart investment in an analyzer helped to protect their biggest investment, the mine, for years to come. Click here to read a more detailed account of the cement manufacturer’s story.