Mass Flow Screw Feeders for Rare Earth Elements

General Description

In 2021, Vital Metals Canada, Ltd. became the first rare earth miner in Canada and only the second in North America. Rare earth elements (REE) are a set of seventeen metallic elements. These include the fifteen lanthanides on the periodic table plus scandium and yttrium. Rare earth elements are necessary components of more than 200 products across a wide range of applications, especially high-tech consumer products, such as cell phones, computer hard drives, electric and hybrid vehicles, and flat screen monitors and televisions. REE is also significant in defense applications including electronic displays, guidance systems, lasers, and radar and sonar systems. Although the amount of REE used in a product may not be a significant part of that product by weight, value, or volume, the REE can be necessary for the device to function. For example, magnets made of REE often represent only a small fraction of the total weight, but without them, the spindle motors and voice coils of desktops and laptops would not be possible.

The ultimate goal of Vital Metals Canada is to become the lowest-cost producer of mixed rare earth oxide outside of China by developing one of the highest-grade rare earth deposits in the world and the only rare earth project capable of beneficiation solely by ore sorting. At the Nechalacho’s North T Zone location, Vital Metals Canada crushes and sorts ore before sending it to their Saskatoon rare earths extraction plant. Upon arrival at the extraction plant, the REE is further processed to purify the materials using various methods depending on chemical composition. This purified material is then stored in large hoppers for future use.

Halyard, consulting engineering company located in Toronto, CA recommended to Vital Metals Canada that mass flow screw feeders would be the ideal solution to accurately metering the REE from the storage hoppers into tubular drag conveyors for conveyance throughout the rest of the process. KWS came highly recommended to Halyard by Jenike & Johanson as the industry leader in the design and fabrication of mass flow screw feeders.

Design Parameters

1. Product Type: Calcined Rare Earth Elements (REE)
2. Material Density: 118 to 144 Lbs. per Cubic Foot
3. Conveyor System Capacity: 26 Cubic feet per Hour
4. Duty: Intermittent

KWS Advantages

Jenike & Johanson provided bulk material testing which determined mass flow screw feeder design. Based on these initial design recommendations, KWS engineers completed capacity and power calculations to finalize torque requirements of the mass flow screw feeders. Because the new screw feeders would integrate with equipment from other manufacturers, the 3D parametric models provided by KWS were vital for a successful installation.

KWS Special Features

KWS utilizes mass flow or cone screw design as the most efficient way of metering the REE from hoppers. The term “mass flow” describes a material flow pattern in which all material in a bin is drawn down at the same rate, regardless of if the material is against the sidewall or in the center. Mass flow allows the bulk material to be drawn down evenly along the entire length of the inlet opening of a screw feeder. Accurate discharge rate is critical to production sequence without surges.

KWS designed the screw feeders with direct drive gearmotors mounted to bulkhead style trough ends. By providing space between the trough end and the drive mounting plate, the bulkhead trough end helps prevent contamination of the drive. It also provides an extremely robust mounting location for heavy-duty gear reducers. The use of high torque output drives ensures the screw feeders will be able to start with a full head load of the very dense, sluggish REE.