Claims:WE CLAIM:
1. A process (100) for making a brick patching material, the process (100) comprising:
crushing a refractory brick of size up to 25mm, the refractory brick being composed of MgO> 92% (by wt.) and Carbon 3-6% (by wt.);
partial calcinating the refractory brick to remove carbon; and
adding a mill scale up to 3-6% in the calcined refractory brick.
2. A method (200) of applying the brick patching material of Claim 1 over a BOF, the method (200) comprising:
adding a BOF slag over the BOF;
adding equal quantity of the brick patching material as that of the BOF slag and mixing by a rocking converter; and
leaving the above mixture over a charging pad of the rocking converter for settling.
3. A brick patching material, comprising:
a partially calcined refractory brick to a size up to 25mm, the partially calcined refractory brick being composed of primarily MgO and a mill scale upto 3-6%, and some inherent impurities.
, Description:BRICK PATCHING MATERIAL
FIELD OF INVENTION
[001] The present invention relates to utilization of waste used brick as patching material for charge pad and tap pad of BOF converter.

BACKGROUND OF THE INVENTION

[002] In BOF steel making refractory linings are used which has a limited life. Higher lining life improves productivity by improving converter availability and reducing specific refractories cost. Due to hostile environment, refractory linings are tended to get damaged. Basic oxygen converters are lined with magnesia carbon (MgO-C) refractories. The causes of wear of refractories in the basic oxygen converter are primarily due to chemical corrosion, physical erosion or thermal impact

[003] Mainly three types of maintenance are done namely gunning, wet patching and brick patching. Wet Patching requires 60 min to 90 min settling time based on amount of patching material whereas brick patching requires 8 Hrs settling time. Hence brick patch is possible only when 8 hrs downtime is available and is rarely practiced. In case of brick patching, life achieved is 100 heats as compared to 20 heats in case of wet patching.

[004] Conventionally to increase lining life slag coating, gunning and brick patching are employed. Gunning and brick patching require long settling time. Such time-consuming activities hampers the productivity. Mag-C Bricks are carbon bonded and around 10 % of graphite is added in the bricks. Graphite has a non-wetting characteristic to steelmaking slags and thereby prevents slag penetration into the brick and subsequent dissolution of the magnesia grains. In brick patching, used bricks are settled in affected area with retained slag. Despite being an effective maintenance practice, it can’t be pursued due to longer maintenance time

OBJECTIVE

[005] The prime objective of the present invention is to provide brick patching material using waste without any binder.

[006] Another object of the invention is to provide quick setting patching material for quicker settling of bricks.

SUMMARY OF THE INVENTION

[007] The present disclosure relates to a process (100) for making a brick patching material. The process (100) includes crushing a refractory brick of size up to 25mm, the refractory brick being composed of MgO> 92% (by wt.) and Carbon 3-6% (by wt.); partial calcinating the refractory brick to remove carbon; and adding a mill scale up to 3-6% in the calcined refractory brick.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[008] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings of the exemplary embodiments and wherein:
Fig. 1: A process for making a brick patching material
Fig. 2: A method of applying the brick patching material over a BOF in accordance with an embodiment of the present disclosure

[009] The figure(s) depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

[0010] The present invention, now be described more specifically with reference to the following specification.

[0011] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0012] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.

[0013] Large quantity of steel is produced employing Basic Oxygen Furnace (BOF) steel making. BOF is lined with a refractory lining which has a limited life. Higher lining life improves productivity by improving converter availability and reducing specific refractories cost. For increasing lining life slag coating, gunning and brick patching are employed. Gunning and brick patching require long settling time. Such time-consuming activities hampers the productivity.

[0014] To overcome the problems associated with the conventional approaches, Fig. 1 illustrates a process 100 for making a brick patching material in accordance with an embodiment of the present disclosure. At step 102, the process 100 includes crushing a refractory brick of size up to 25mm for increasing the surface area. In an example, the refractory brick is composed of MgO> 92% (by wt.) and Carbon 3-6% (by wt.).

[0015] At step 104, the process 100 includes partial calcinating of the refractory brick to remove carbon. In an example, partially calcined dolomite (calcium magnesium carbonate, ideally CaMg(CO3)2) with small amount of iron was also added with slag. At step 106, the process 100 includes adding a mill scale up to 3-6% in the calcined refractory brick.

[0016] In an embodiment, a settling time associated with the brick patching material reduced to fifteen (15) minutes, as compared to conventional approaches. This happened because of the faster formation of magnesia wustite bond due to the larger surface area and more porous mass due to absence of carbon. Further, this material consisting of waste brick and slag calcined dolomite can replace costly patching material. Also, this will eliminate the addition of patching. Further, Quick setting patching material was developed in house utilizing waste refractory bricks and calcined dolo which resulted in saving of 70% of maintenance time.

[0017] Fig. 2 illustrates a method 200 of applying the brick patching material over a BOF in accordance with an embodiment of the present disclosure. At step 202, the method 200 includes adding a BOF slag over the BOF. At step 204, the method 200 includes adding equal quantity of the brick patching material as that of the BOF slag and mixing by a rocking converter. At step 206, the method 200 includes leaving the above mixture over a charging pad of the rocking converter for settling.

[0018] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims.