Slag Processing

Raw slag is usually received from the refining operations with some metal still remaining in it.

The separation of slag and metal can never be precise, since slag always floats on iron or steel. It is preferable metallurgically to leave some metal in the slag, rather than to have some slag in the metal.

When solidified, this large chunk of metal is called a skull, and needs to be broken into usable sizes and the adhering slag removed. This is usually done by a lift crane with a large dropball to impact the skull. The drop ball may either be captive (attached to a lifting cable) or a free ball (lifted by a cable hoisted electro-magnet which releases the ball by de-energizing the magnet).

The slag is fed through a grid by a front loader or truck.  Another magnet crane may be used to pick up the metal which is too large to pass through the grid, and to assist with pushing the slag pieces through the grid.

The smaller pieces of metal are removed by 3 or 4 smaller magnets during the crushing and screening stages.

There may be a separate metal screening facility in the process flow to separate the scrap into

steel furnace, blast furnace, or sinter plant feed sizes.  The latter two are used only in integrated steel mills.

Dust control during processing is important.  This is accomplished by water cooling before feeding slag to the plant and further controlled by water addition during processing.  Sometimes an oxidizing agent is used in the water to suppress gas emissions.

Water addition is limited so that the products are not sticky (which causes adhering fines), but enough is added to suppress dust emissions.

Where needed, our patented temperature and dust sensing mechanisms are used early in the process, with metered water additions as needed further along in the process based on the sensor readings.

In some cases, many narrow slag sizes are produced, binned, and proportionately blended to make products to prescribed specifications. 

In other cases, screening facilities can be designed to produce finished aggregate sizes which meet specified requirements.