Taking into consideration the natural environment and the water challenge in Brazil, to produce a high-quality concrete sand

Client : Mineradora Curumim

Taking into consideration the natural environment and the water challenge in Brazil, to produce a high-quality concrete sand

Presentation of the project

The company Mineradora Curumim already operates in the north of the state of Sao Paulo a pit, with a relatively common local technology: feed from a dredge to a single cycloning unit and rejection of the underflows on a pile stock:

The strong growth in Brazil generates significant needs, along with the quality of construction is reinforced: the requirements in terms of quality of concrete sands also become stronger and require more efficient technologies ...

However, the ecological pressure in Brazil and in the rest of the world require manufacturers to better manage natural resources , especially water. If Brazil has a signifiant amount of water, it's irregular in particular in the state of Sao Paulo, and the authorities ensure it's responsible and rational use : it is almost impossible to open a pit or a quarry without presenting a plan for water management and production wastes.

Mineradora Curumim acquired an operating license for a new site in Enhembi. The project consisted of organizing a water storage to feed a dredge to extract a 0/1.5 mm sand, in order to produce a high quality concrete sand , with a precise specifications and demanding ratios of cleanliness. The operating license was related to the presentation of a water management plan , with the organization of an efficiant recycling process regarding water.

It just so happens that there is no Brazil industrial ensuring a complete industrial partnership to support these type projects: analyze, design, manufacture, install and train operators under one responsibility, ensuring the performance of the installation.

Technical challenges and provided solutions

Mineradora Curumim asked MS to define a tailor-made solution of sand valorization and water recycling to operate in closed-circuit.

The sizing data were as follows:

  • 300 T/h of pumped aggregates, with up to 255 T/h of 63mm/1,3mm and  45 T/h fine particles.
  • 800 m3/h of washing water to be clarifed

The entire project was subject to three functional constraints namely: 

  • Reach values ​​of cleaness of sands despite altered aggregates (up to 3% < 63mm ) 
  • Maintain a residual moisture of 15% in the sands  
  • Ensure an efficient recycling of water to feed the installation in closed circuit

After analysis of samples in our laboratory , consultation and reflection , MS proposed the establishment of a sand treatment unit composed of a cycloning/dewatering unit and a a water treatment plant composed of a 16m thickener.

The entire process is summarized in the flowsheet below:

Sand treatment plant

The sand is pumped from the dredge and sent to the feed hopper which allows the elimination of waste such as wood. Raw sand is then sent to a double MS sand treatment plant which enables to treat on each side of the installation, 550 m3/h of pulp. Each side is fitted with a sand pump, two cyclones cutting at 63 microns which enables to produce from the underflow, a clean sand still containing a certain percentage of water. The choice to install two smaller cyclones is motivated by the fineness of the sand to be treated, enabling to ensure an optimum productivity with the finest possible cut.

The sand from the cyclones underflows is sent to two dewaterers which enable to reduce moisture content in the washed sand, to recover more water and therefore to reduce water consumption in the process.

The feed tank receives filtrates from the dewaterers and is controlled thanks to a floating valve connected to the water box receiving the overflow of the cyclones, thus optimizing the alimentation of the cyclones.

The remaining flow of washing water (800 m3/h of water containing 40 T/h of fine particles ) is sent to the water treatment plant.

 

 

Sand valorization and treatment plant

Dewatering of sand


Washed 0/2 mm sand

Water treatment plant

Washing water from the sand treatment plant are sent to the thickener which enables to concentrate sludge through an automatic dosing and injection of flocculant. MS thickener is fitted with the last improvements on the box flocculation, the flocculation controller and the scraper. A technical room comprising the Dosafloc, the Controlfloc and the power cabinet is installed on the thickener.

The clarified water from the overflow the thickener is discharged into a tank. Two water pumps feed the sand treatment plant in closed circuit , thus enabling 85% recycling of process water.

Sludge is concentrated at the bottom of the thickener thanks to a pendular scraper, a sludge pump allows to transfer it from the bottom of the thickener to the sedimentation pond.

Thickener

Controlfloc


Concentrated sludge at 500 g/l

Transport / Erection / Commissioning

These two units were pre-assembled and pre-wired in MS workshops, thus ensuring an optimum transport, a fast and easy erection on site, as well as a more efficient commissioning.

Pre-assembly and pre-wiring in our workshop

Optimised packing

Fast & easy erection on site