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Recycling or disposing of Mill scale

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Q. My company generates about 400 tonnes of mill scale from its hot rolling ( of steel) operation. This waste material is becoming on environmental problem due to accumulation. Can anybody suggest an efficient way to dispose or recycle this material ?

Edgar C. Marquez
- Philippines

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A. A fungi based biodet has the capability to solubilize about 2 kg of mill scale per litre. It can also be recycled once contaminated.

Edward Petermann
- Kitchener, Ontario, Canada

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A. I suggest contacting your government agricultural ministry for assistance. This material could possibly be used as an iron-rich soil supplement. Laboratory analyses for metals such as Cr, Cu, Ni, and Zn would be necessary. However, trace amounts may be beneficial in some leached tropical soils. With government approval, you may also want to investigate whether a more soluble form, as by reaction with spent sulfuric acid pickling solution, would be beneficial.

Ken Vlach - Goleta, California

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A. Komesta Edgar,

More years ago than I care to remember, I worked in a hot strip mill, the mill scale was sent to the blast furnaces for recycling. If you don't have an iron making blast furnace you may want to briquette the mill scale and feed it back into the steel furnaces. Some binders used on ore and scrap fines were pre-jelled starch or sodium silicate in very small percentages.

Good Luck & Best regards,

Jim Sivertsen
- Alden, New York, U.S.A.

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October 30, 2009

Hello Jim,

I'm interested in your idea of briquetting the mill scale for steel furnaces. In my country, we have electric arc furnaces for steelmaking.

Is it feasible to use in electric arc furnace? What is the recovery of iron/steel?

Thanks.

Edgar C. Marquez (returning)
- Philippines

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September 28, 2008

A. You can export the mill scale to China as the demand is increasing by the day for sinter plants.

Abhishek karnani
- kolkata, wb, india

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July 12, 2011

I came to know that in China mill scale is being recycled by the following process.

They first grind the mill scale to some specific grain size then pass it to magnetic separator and then mix it in mixture with coal powder and some binder then make briquettes using hydraulic press and then these briquettes being used by foundries casting cast iron components in their coke fired cupola furnace called smelting reduction process.

But I've not seen this process live and that's why I'm searching out China where this is practiced.

Can anybody help me in this matter? Because I also want to recycle mill scale in my foundry line.

Mukul Gupta
- Phagwara, Punjab, India