High Temperature Kiln Injection Screw Feeder for Electric Arc Furnace (EAF) Dust

General Description

Clariant is a leading specialty chemical company that provides green and sustainable products based on natural ingredients that are free of harmful substances. Through the extensive use of renewable resources, Clariant drives a circular economic solution. Clariant products create value through enhanced sustainability by reducing dependency on fossil resources to reduce CO2 emissions.

Electric Arc Furnaces are mainly used in the recycling of scrap iron and steel. The dust given off can be toxic and must be collected by air pollution control equipment. Electric Arc Furnace (EAF) dust can contain heavy metals, such as zinc, lead, and dioxins. It is categorized as hazardous industrial waste and requires proper disposal. KWS designed and manufactured a screw feeder to meter EAF dust into a kiln so heavy metals could be extracted.

Design Parameters

1. Product Type: Electric Furnace Dust
2. Material Density: 56 Lbs. per Cubic Foot
3. Capacity: 21 Cubic Feet per Hour
4. Designed Duty: 24 Hours per Day, 7 Days per Week

KWS Advantages

KWS has developed screw feeder designs for metering and injecting bulk materials into kilns, calciners, and dryers. Knowledge and expertise of bulk material handling as well as heat transfer, and proper selection of materials for operation at elevated temperatures is extremely important for successful, long-term operation. KWS currently has over 1,000 kiln injection screw feeders operating in the US and around the world.

KWS Special Features

Since the kiln was operating at 1500-degrees F, 304 stainless steel was used to construct the screw feeder. KWS also provided Nitronic 60 wear bars inside the tubular housing to guide the EAF dust into the kiln. Nitronic 60 is a high strength, high temperature stainless steel alloy with excellent corrosion and abrasion resistance.

The KWS screw feeder was designed to be cantilevered, and only supported at the drive end. Since the discharge end of the screw feeder was inside the kiln, bearings and seals would not hold up to the extreme environment. The cantilevered screw discharged the EAF dust directly out of the end of the tubular housing directly into the kiln. The bearings and drive unit are located outside of extreme heat and operate at ambient temperature.

Variable pitch screw accurately meters the EAF dust into the kiln and draws down the material in the hopper at the same rate and evenly along the entire length of the inlet opening.