Continuously Operating Ploughshare® Mixer Type KM
Thanks to their high throughput rates, the process engineering systems of Lödige Process Technology meet the demands of the chemical industry for economic production. For a great example, look no further than the versatile Ploughshare® Mixer KM: It permits production of monocalcium phosphate (MCP) in an “all-in-one” process.
Monocalcium phosphate, identified by the chemical formula, Ca(H₂PO₄)₂x H₂O, is an essential component of animal feed and phosphate fertilisers. The colourless, moderately water-soluble powder is produced by a reaction of pure phosphoric acid with calcium carbonate. Powerful process technology is just as important to the production of high-quality MCP as the quality of the raw materials used. Lödige offers a solution that is specially designed for this application, based on a type KM Ploughshare® Mixer for continuous operation.
Ploughshare® Mixer with application-specific design
The Ploughshare® Mixer for continuous operation uses the mechanically generated fluid bed system that was introduced to mixing technology by Lödige: Ploughshare® shovels in their basic shape patented by Lödige in 1949 rotate close to the walls of a horizontal, cylindrical drum. The circumference speed and geometric shape of these plough-like mixing tools are designed so that they pick up the raw materials for the mixture completely and throw them into the free mixing compartment. During this process, the material is lifted off the drum wall against the centrifugal force. This generates a mechanical fluid bed, in which the entire product mixture is constantly gripped, resulting in extremely thorough mixing, even with high mixture throughput and short retention times. The mixing elements are shaped to ensure product transport. Additional choppers in the mixing drum break up agglomerated material and permit systematic granulation during the mixing process.
The result is a continuous “all-in-one” process. This means all process phases of MCP production can be performed in a single machine. Other units and process steps are no longer necessary. Moreover, the mixer offers great stability and minimised cleaning intervals. A special wear protection shields mixing tools and shovel arms against the high mechanical and corrosive stress caused by contact with the mixture.
The MCP production process has three phases: mixing – reaction – granulation. In the first step, the two base materials, phosphoric acid and calcium carbonate, are mixed to form a highly homogeneous substance. In the second phase of the process, an exothermic reaction is produced under defined conditions, resulting in a conversion of the base materials into monocalcium phosphate. This is followed by granulation in phase 3. The granulate properties can be adapted specifically to the customer’s requirements. The final process step, granulation, offers a variety of advantages over ungranulated MCP: It improves the pourability of the substance and makes transport and storage easier. It allows the product to be packaged dust-free and permits perfect dosing.
A variety of different machine sizes is available for throughput rates in a range from 1t/h to 50t/h.