Considered São Paulo’s most urban quarry, Pedreira São Matheus do Lageado is one of the first in the country to produce manufactured sand; it has been in operation since March 2017. With a capacity of 70 tons/hour or 15,000 tons per month, the unit has overcome the initial challenges of inconsistent product quality and poor market acceptance of the different color and texture. “In reality, we produce sand and that’s it,” summarizes Marcos Roberto Santos, the mining engineer in charge of the plant.
“We collect samples and meet face to face with personnel from the concrete plants and manufacturers of high-strength concrete blocks. We work together to suggest characteristics, distribute products, and perform laboratory testing, but, most importantly, we stress that the product we are offering is sand,” he adds. According to Marcos, the consumption of manufactured sand does not compete with that of natural sand. He is, in fact, in favor of combining the two, as long as the exploration takes place in accordance with environmental standards.
Convincing smaller businesses
“We are offering a product with a sustainable design and invariable composition and grain size due to the industrialization process,” says the engineer. “At the same time, the consumer can be sure that they are using a standardized product.” According to Marcos, current clients include the companies with which Lageado has carried out testing and results analysis.
Having overcome the professional consumer challenge, the engineer believes that manufactured sand producers should now focus on the consolidation of the product for small consumers. The list includes professionals in charge of small construction sites, engineers, construction companies, bricklayers and master builders.
Metso was chosen for its technical know-how
“We adopted Metso technology because the company is a pioneer in the process of dry sand production - and also obviously due to the successful technical and commercial relationship that already existed between the two companies,” explains Marcos. Automation of the plant, including supply control and load flow, thus allowing for operation with minimum human interference was another important consideration.
One of the achievements of the activation of the unit was the project design, which was drawn up in close collaboration with Metso. Marcos also highlights that with the production of sand, the company has added at least two more products to its sales portfolio, and it no longer has stone powder as a crushing line by-product.
Even the filler, which is extracted from sand using the Metso air classifier, can be commercially used in the surfacing of highways.
Lageado’s numbers reflect the changes. At the time of the line’s commissioning, the company had an input of roughly 80 t/h, with 12 t/h classified during screening and separated as clean gravel (4.8 to 12 mm). The air classifier, on the other hand, had an input of 68 t/h with a filler removal rate of roughly 6.4 to 7%.
Now that the operation is stabilized, Lageado works with an input rate of 110 t/h, with 25 t/h being classified as clean gravel. Filler removal is at roughly 9% in order to meet the requirements of the company’s main clients.
The structure of the plant for the production of sand
“The sand plant designed for Pedreira São Matheus do Lageado is very simple, yet extremely functional and productive,” says Maria Thereza Müsel, Key Account Manager for Metso Brasil in the field of aggregates. She continues by explaining that the operation comprises three units of equipment. The first is the autonomous Barmac® crusher, which improves the cubicity of the material, making it similar to the type of sand that can be found in a river. The second is a Metso CBS screen, which gives the plant its flexibility: it allows for the production of material that is thicker than sand or for a standalone product as per market demand.
The third unit is the Metso Air Classifier, considered the heart of the plant, for the extraction of filler from the sand. With these three devices in place, Lageado produces and stores the sand in a “bean” type stack, created using the conveyor belt. “The unit also has an automation system in order to guarantee that the appropriate input rate is being observed,” Maria Thereza concludes.
As a long-term partner, Lageado uses Metso’s equipment in its crushing and sand production plant. The company calls itself São Paulo’s most urban quarry, since it is located 20 km from the center of the capital of Brazil’s richest state. It has been in operation for over 60 years and its main focus is the civil construction market. The manufactured sand production project was conceived by the company as a result of its differentiated and environmentally-focused management.
This commitment can be seen in the study of the destination of the manufactured sand by-products in applications within the ceramics industry, according to an official report by Lageado. The manufactured sand currently being produced has a vast field of application: it is used in the production of structural concrete made in concrete mixers or concrete plants, in asphalt plants (CBUQ, PMF and PMQ), in facilities for precast concrete (slabs, blocks, pipes and interlocking floors), as a drainage product, and also for filters in sewage treatment stations.