Method for Separating Mill Scale from Wastewater

Patent metadata

Field	Value
Publication number	US-2018229155-A1
Application number	US-201615749865-A
Country	US
Kind code	A1
Filing date	Sep 6, 2016
Priority date	Sep 4, 2015
Publication date	Aug 16, 2018
Grant date	—

Abstract

A method for collecting mill scale from a hot rolling mill is provided. The hot rolling mill includes a flume. The method includes transporting mill scale particles in wastewater, retrieving the wastewater from a flume of the hot rolling mill and separating the mill scale particles from the wastewater using a separator. A hot rolling mill and a method for retrofitting a hot rolling mill are also provided.

First claim

What is claimed is:

1 . A method for collecting mill scale from a hot rolling mill, the hot rolling mill including a flume, the method comprising the steps of:
transporting mill scale particles in wastewater; retrieving the wastewater from a flume of the hot rolling mill; and separating the mill scale particles from the wastewater using a separator.

2 . The method as recited in claim 1 wherein the separator is a grit separator.

3 . The method as recited in claim 1 further comprising the steps of collecting the mill scale particles.

4 . The method as recited in claim 3 further comprising the step of:
dewatering the collected mill scale.

5 . The method as recited in claim 1 wherein the wastewater is turbulent or running at high speeds in the flume.

6 . The method as recited in claim 1 wherein the separator is provided downstream from a reheat furnace, scalebreaker, roughing stand, cooling stand or finishing stand.

7 . The method as recited in claim 1 wherein the separator is located in the flume.

8 . The method as recited in claim 1 wherein the separator is located upstream of a pit.

9 . The method as recited in claim 1 further comprising the step of:
directing the remaining wastewater downstream in the hot rolling mill.

10 . The method as recited in claim 9 , wherein the remaining wastewater is directed to a pit.

11 . The method as recited in claim 1 , wherein the mill scale is separated from the wastewater in accordance with the following formula:

c
=

hu



τ

dp

,

%



wt

;

wherein:
c is oil concentration in the collected mill scale in % wt,
h in g/mm 2 .s is a coefficient,
u is oil content in wastewater in % wt before mill scale is collected,
τ is contact time in s between scale particles and oil droplets before the scale is collected; and
d in mm and p in g/mm 3 are size and density of the collected scale.

12 . A hot rolling mill comprising:
a reheat furnace for reheating a steel slab; at least one stand for processing the steel slab downstream of the reheat furnace; a flume connected to the at least one stand transporting mill scale particles and wastewater; and a separator in the flume for separating mill scale particles from the wastewater.

13 . The hot rolling mill as recited in claim 12 further comprising a pit downstream of the flume.

14 . The hot rolling mill as recited in claim 12 wherein the at least one stand is a scalebreaker, roughing stand, cooling stand, finishing stand, cooling and run out table or coiler.

15 . The hot rolling mill as recited in claim 12 further comprising a washing device downstream of the separator.

16 . The hot rolling mill as recited in claim 12 further comprising a dewatering device downstream of the separator.

17 . A method for retrofitting a hot rolling mill including a flume comprising the step of:
placing a separator into the flume.

Assignees

• Arcelormittal

Inventors

• Ma Naiyang

Classifications

• B01D21/0012 Primary

  Settling tanks making use of filters, e.g. by floating layers of particulate material · CPC title

• B21B2001/225

  by hot-rolling · CPC title

• B21B2001/028

  Slabs · CPC title

• B21B1/26

  by hot-rolling {, e.g. Steckel hot mill} · CPC title

• B01D21/267

  by using a cyclone · CPC title