Method for degreasing rolling mill scale

Claim 1

A method of treating grease-covered rolling mill scale from rolling mills, especially hot rolling mills, by means of solvents, which includes the steps of: weighing the rolling mill scale to be treated, thoroughly mixing the weighed rolling mill scale with an amount of oil-free grease solvent from 10 to 20% by weight of the scale to form a mixture while finely distributing the grease in the mixture, adding said mixture in a continuous manner to a bath containing grease solvent and distributing said mixture therein, slowly moving said rolling mill scale out of said solvent-containing bath subsequently mixing said rolling mill scale after it has been moved out of the bath with additional oil-free grease solvent passed in counter-current flow to said mill scale, continuing the movement of the mill-scale and draining off solvent containing grease from the rolling mill scale leaving substantially grease-free mill scale, regenerating the grease-containing solvent by distilling it and condensing oil-free solvent therefrom, recycling the condensed oil-free solvent to mix with additional grease-covered rolling mill scale to be degreased, moving the substantially grease-free mill scale on a helical reciprocatory plate feeder and contacting the mill scale with grease solvent vapors while it is being moved on said feeder, discharging the mill scale from said feeder into a bath of hot water at a temperature sufficient to heat the rolling mill scale and to drive residual solvent therefrom, and removing the mill scale from the hot water bath.

Claim 2

A method of treating grease-covered rolling mill scale from rolling mills, especially hot rolling mills, by means of solvents, which includes the steps of: weighing the rolling mill scale to be treated, thoroughly mixing the weighed rolling mill scale with an amount of oil-free grease solvent from 10 to 20% by weight of the scale to form a mixture while finely distributing the grease in the mixture, adding said mixture in a continuous manner to a bath containing grease solvent and distributing said mixture therein, slowly moving said rolling mill scale out of said solvent-containing bath subsequently mixing said rolling mill scale after it has been moved out of the bath with additional oil-free grease solvent passed in counter-current flow to said mill scale, continuing the movement of the mill-scale and draining off solvent containing grease from the rolling mill scale leaving substantially grease-free mill scale, regenerating the grease-containing solvent by distilling it and condensing oil-free solvent therefrom, recycling the condensed oil-free solvent to mix with additional grease-covered rolling mill scale to be degreased, moving the substantially grease-free mill scale on a helical reciprocatory plate feeder and contacting the mill scale with grease solvent vapors while it is being moved on said feeder, discharging the mill scale from said feeder into a bath of hot water at a temperature sufficient to heat the rolling mill scale and to drive residual solvent therefrom, and removing the mill scale from the hot water bath.