Material unloading is a very dusty process
Material in silos is typically very dry, e.g. fly ash. Very often it is unloaded for further transportation outside the works by trucks, which are not covered. It will inevidently result in vigorous dusting. This is an very local environmental issue, but very importantly also a labor hygiene issue. This problem can be overcome by wet unloading. Compared to our dry unloading system, the wet unloading system is suited for facilities which require material to be unloaded to an open truck through an open material handling system.
Add a little water into the mix to ensure dustless unloading
Kopar has developed a special device for wet unloading. It is an open two-axle double spiral screw mixer with extra pads / open double spiral screw conveyor positioned horizontally. There water is sprayed in a controlled way and thus, the moisture content in the final product can easily be adjusted to any desired level needed to prevent dusting. A single device can handle a capacity well from 75 to 100 m3/h. As many equipment used in material conveying / transportation are based on volumetric capacity, it is eventually the bulk density of the treated material which determines the actual mass flow based capacity. With fly ash the actual capacity is well over 50 tons per hour.
In order to supplement our product portfolio, and give flexibility with respect to layout, Kopar has co-developed a fully new product – patented one – for the same application. There gravity in utilized whilst the material drop downward. Simultaneously, either water or steam is added through rotating paddles which results in very uniform moisture content through the wetted product. Use of steam bring benefits especially for the homogeneous final moisture level. This vertical mixer / wetting device has practically equal design basis for the capacity, but in smaller space.
Both of out wetting systems for unloading comprise fluidization system of the preceding silo, accompanied with a rotary feeder, both of which have been built and designed in-house at Kopar. Easy to operate, the system can be used completely remotely. No need for dedicated personnel, the driver can handle using the remote unloading system.
Also mixing function without water addition applicable
Both mixers can also be used for pure mixing purposes, e.g. for mixing dry and/or wet material streams together in order to form a reasonably homogeneous mixture. This can easily be applied for stabilizing final waste before permanent land-filling.
Typical specification are as follows:
Capacity: 75-100 m3/h
Capacity: Over 50 t/h
Space requirement: 1 x 1,2 x 4,1 m – horizontal screw mixer
Space requirement: 1,2 x 1,3 x 1,3 m – vertical paddle mixer
Suitable usage cases
- Energy and power industry: Wetting of fly ash at unloading
- Chemical & mineral industry: Mixing of fine dry materials with moist residue
- Metal industry: Stabilization of land-filled wastes