Lime as an Operational and Environmental Necessity

Q: What are the vision and strategies that have placed Grupo Calidra as the leader of the lime industry?

A: Grupo Calidra was founded over a century ago by a German family that came to Mexico to work on the construction of the city’s sewage systems, during the time of Porfirio Díaz. To conduct their operations they needed lime and eventually became their own lime suppliers. Some years after Grupo Calidra was established they introduced industrial lime hydration methods being used in Europe, and patented the technique in Mexico to open a new, niche market for hydrated lime in the construction sector. During the 1950s Grupo Calidra identified the opportunity to supply lime for industrial processes. To capitalize on it the company had to modernize its operations and introduced the first rotary kilns to produce lime of a higher quality, initially for the oil and steel industries that were flourishing, and later in other growing markets such as the corn, sugar and paper industries. During the 1980s the decision was made by the owners to grow the business by creating a joint venture with Belgian investors that helped the company to understand the importance of continuous investment in modern technology, improving the knowhow of its employees, enhancing its operational structure and implementing ambitious growth strategies.

Q: Why is it important to use lime-based products for the treatment of hazardous residues?

A: Acids are used to extract the metal from the mineral. The use of specific acids will depend entirely on the metal that is being extracted; it can be used to extract anything from precious metals to base metals and common iron. The most common application of lime in mining operations is in heap leaching, in which a large amount of the extracted mineral is piled up, and acid solutions are poured on to dilute the material and recover the desired metals. Acids such as cyanide can have a major impact on the environment, and it is also very dangerous for humans, but if you increase the pH level and keep the cyanide in the alkaline base then it is not dangerous at all. Lime is used to transform an acid solution into a base solution, helping mining companies to maintain control over hazardous residues; in this way Grupo Calidra contributes to creating cleaner and safer industries.

Q: What other advantages does lime have for reducing the negative environmental impacts generated by mining operations?

A: In terms of the environment, lime is the most economical and reliable technology out there. Lime has very significant advantages for reducing environmental impacts in mining. For example, lime products have been used to raise the pH of soils that are contaminated with heavy metals. This treatment immobilizes the metals and enables the land to be used for growing forage crops and grass. Waste water from mining operations contains dissolved metals, which have to be removed or reduced to acceptable levels before being released into the water system, so liquid effluents are also treated with slaked lime to neutralize acidity. Another important application is in soil stabilization. In Mexico it is very common to find very uneven roads; this is because previously there has not been any treatment of the soil, and lime is a very economical and reliable solution for stabilizing the clay. For many years we have told miners to stabilize their roads, because those who do not will suffer great losses and have to pay over and over again to repair their trucks and replace tires. Those who have stabilized their roads have been very happy with the results.

Q: What are Grupo Calidra’s tried and tested technologies for guaranteeing the quality of its products?

A: Grupo Calidra has chosen to use Maerz technology, since its ovens can guarantee the purity of the product that comes out. This is possible because the equipment uses lesser contaminated fuel sources, such as natural gas. It took many years and a lot of ingenuity to develop the current Maerz technology, which is capable of giving a steady and controlled flow of stone, air and fuel. The type of technology we use comes down to what the customer is asking for, because the process depends on the needs of the customer. For instance, if the customer is looking for construction lime, then the purity of the fuels being used to power our technologies is not so important, because for this purpose the highest purity lime is not a requirement. However, when the steel and glass markets demand products with a small proportion of magnesium it is important to use the right methods to exploit our dolomitic limestone deposits, and also to use the right calcination techniques to create the requested product.

Q: What are Grupo Calidra’s expansion plans for the coming years?

A: The mining industry is the second biggest user of limebased products, after construction, and Grupo Calidra’s expectations are to keep growing within the mining sector. The company has recently started to establish itself near mining sites, since this strategy will favor both parties – the company and the client. Since we have now completed the modernization and expansion of our operations in Mexico, our plans are essentially to continue looking at the trends and keep on growing steadily here, along with the market. We have also now started to expand internationally – we will install two plants in Peru soon, and it is very likely that we will install another in Colombia. From there we would also like to serve the Caribbean regions.