EQUIPMENT FOR THE CONSTRUCTION SAND INDUSTRY
– AKOREL FREE-FALL CLASSIFIER –
For many years the AKOREL free-fall classifier has proven to be the suitable equipment for the processing of high quality construction sand. With this apparatus one or two quality sands with the desired grain size range (plus an uncontrolled sand grade) can be produced by blending from 6 to 16 individual grain size fractions via user programmable control unit.
AKW Equipment + Process Design can refer to several successfully realized projects with installations of the different versions of our AKOREL, be it in France, Switzerland, Poland, Austria, Ireland or Germany.
An impression of the free-fall classifier performance in the construction sand industry is provided below.
One of our German customers, Münchner Kies Union GmbH & Co. Sand- und Kieswerke KG, supplies the market with natural sand (0-4 mm), crushed sand (0-2 mm) as well as grit (2-5 mm, 5-8 mm, …). For the production of these different types of sand a plant needed to be erected. Therefore AKW Equipment + Process Design was asked to evaluate and integrate its free-fall classifier AKOREL, type 28/120, in the overall process. In natural sand the sieve curve mostly does not meet exactly the requirements for building sands. To correct these discrepancies in sands (0-4 mm) the free-fall classifier is used. This technology was developed to divide the feed sand into 12 fractions from coarse to fine and to mix the different grades by a PLC-System to a high quality sand with an accurate sieve curve according to the requirements. In the actual case the AKOREL is equipped with two chutes, one for the concrete sand product the other one for the “undefined by-product”. The latter mainly contains finer fractions. The loss of material is below 5 %, the product output according to the flowsheet is at 260 tph with a grain size of 0,125 up to 4 mm.
Upfront to the AKOREL stage a classification at 4 mm is installed. The underflow feeds the AKOREL. Alternatively crushed sand can be added. The two products are dewatered via dewatering screens and stockpiled. The fine sand in the overflow of the AKOREL and the underflow of the dewatering screens are recovered through hydrocyclones and fed back to the AKOREL.
|Tank length / widht / height||12000 mm / 2800 mm / 2800 mm|
|Feed material||Sand 0-4 mm|
|Output material||Sand 0,125-4 mm|
|Capacity per hour||max. 260 t/h|
|Feed concentration||approx. 300 g/l (910 m³/h slurry, max. 1000 m³/h)|
|Upstream water demand||approx. 250 m³/h – internal circulation water|
IMPRESSIONS OF THE MOUNTING PHASE
THE EQUIPMENT CONSISTS OF THE FOLLOWING ELEMENTS
- 1 rubber-lined inlet box, aimed at reducing turbulences
- 1 classifier tank (primed inside, with cover coating on the outside, total layer thickness min. 120 µm) with chamber division for the first three stations in this section, rubber-lined
- 1 overflow collecting launder on the two long sides and discharge pipe connections on the wide side of the classifier opposite the feed, engineered from steel plate with sectional steel reinforcement, and built-in sump for the upward current water pump
- 1 distributing pipe for the upward current of water attached at the side, with three discharge connections, rubber-lined, and three manual flat slide valves
- 12 blade-type level height measurement devices, electrically powered
- 12 bottom valves, each actuated by one pneumatic cylinder
- 12 discharge pipes, which are slewed into the necessary discharge positions by means of pneumatic cylinders
AKOREL product collecting launder
- 2-part discharge launder made of steel plate and lined with wear-protective material
- Siemens S7 with WinCC for a flexible production (handling of varying input and output recipes)
IMPRESSIONS OF THE AKOREL IN OPERATION
With the integration of AKW Equipment + Process Design´s AKOREL free-fall classifier we are able to improve the sieve curve according to our requirements. We are very satisfied with the performance of the equipment and the whole plant“, stated our German customer.