RH Degasser

maf-anov-rh-degasser-mainOur company is a manufacturer of basic refractory materials. Modernisation changes in metallurgical industries make it necessary to conduct continuous research and development works, which result in new structural and material solutions to satisfy growing customers’ expectations.

A special attention should be paid to the full lining for the RH vacuum steel degassing chamber, as well as the development and implementation into production in 1997 of our own construction of complex, high-processed, ready-to-install snorkel sets for this installation.

The snorkel construction and the type of materials have especially been developed to minimise the influence of numerous destructive factors, such as erosion by the steel jet, as well as corrosion by slag and alloy additions, intensified by vacuum and thermo-mechanical stresses, increased by variations of temperature in the refractory lining of snorkels caused by their periodic operation.

In order to prolong the RH snorkel service life, patching mix is offered together with the device for its spraying.

The close many-year cooperation between us and the end-users in the area of refractory lining modernisation and optimisation produces effects in form of a continuously increasing service life of thermal vessels. Design of refractory linings for thermal vessels is accomplished in a modern designing office.

Awards

Full lining of the snorkel for vacuum steel degassing in the RH installation was awarded with a Silver Medal on the 48th World Exhibition of Innovations, Research and New Technologies “Brussels – Eureka ‘99” and with the European Medal for Product in 2001.

BASIC REFRACTORIES FOR RH DEGASSERS

Quality Chemical Analysis [%] Open Porosity Bulk Density Cold Crushing

Strength

Refractoriness

Under Load

MgO Al2O3 Fe2O3 CaO SiO2 Cr2O3 % g/cm3 MPa T0,6°C
Magnesia-chromite bricks
Betmag BMCT 52 6,5 11 0,9 3,6 24 18 3,12 40 1650
Topkrom MCR54) 66,0 4,9 9,4 1,2 0,9 17,6 15 3,25 100 >1700
Topkrom MCZ214) 65,8 4,3 7,0 0,9 0,9 21,1 16 3,22 60 >1700
Topkrom MCB 61,4 5,7 13,4 1,2 0,6 17,1 19 3,20 50 >1700
Topkrom MCSW 56,2 6,3 12,6 1,0 1,5 20,1 19 3,10 65 >1660
Topkrom MCW15 65,0 4,8 9,3 0,4 1,8 16,0 18 3,00 60 >1700
Topkrom MCW22K 57,5 6,4 11,1 0,7 1,3 23,1 17 3,15 60 >1700
Topkrom MCT 54,5 6,9 13,0 1,0 1,0 22,9 15 3,32 70 >1700
Topkrom MCV 53,0 7,0 13,1 1,0 1,1 23,3 16 3,29 80 >1700
Construction-and-repair mixes
Konmix MKX2 56,0 6,3 12,8 1,2 1,9 19,0 22 2,90 >25 >1700
Konmix MKX2L2) 52,5 6,4 10,9 0,9 3,6 24,0 18,5 3,05 40
Konmix MKX3 92,0 0,7 1,9 0,7 2,6 29 2,46 12
Gunmix BALM/BTM3) 83,0 1,5 4,0
Gunmix MTRH3) 79 6,1 2,0 4,8 6,7
Low-cement castables
Runcast BMAL/L2) 4,5 93,0 0,1 1,5 16 3,00 40 1650
Runcast BALM/ASM) 68,0 0,5 2,5 27,0 22 2,65 80 1420
Runcast BMAL/MS1) 4,5 92,5 0,1 1,6 14 3,05 50 >1700
Runcast BMAL/M55S1) 5,0 93,0 0,1 1,3 13,5 3,10 80 >1700
Runcast BKW/M Al2O3+MgO=97 0,1 1,6 12 3,10 150
Maskor MSK 78,5 0,2 0,6 15

SiC

13 3,00 45

1) – with steel fibers added.
2) – self-flowing material.
3) – gunning mix for snorkels.
4) – additional designation at the end of the name: RC – ground shapes RB – ground and assembled shapes NSM – impregnated material.
The above data are typical and may not be treated as conditions of acceptance.

There is a possibility to choose refractories individually, according to the settlements with the customer. We employ the ISO 9001:2000, ISO 14001:2004 and PN-N-18001:2004 management systems in the field of design, manufacture and supply of basic refractory materials.

RH Degasser Refractory Lining

A – EXHAUST DRAUGHT WORKING LININGmaf-anov-rh-degasser-refractory-lining
B – EXHAUST DRAUGHT SAFETY LINING
C – UPPER VESSEL WORKING LINING
D – ALLOY CHUTE WORKING LINING
E – ALLOY CHUTE AND BURNER OPENING SHAPES
F – LOWER VESSEL SAFETY LINING
G – LOWER VESSEL WORKING LINING
H – SNORKEL OUTER WORKING LINING
I – BOTTOM WORKING LINING
J – SNORKEL INNER WORKING LINING
K – MIX AND CASTABLE FOR GAP FILLING

Grinding process

The operational durability of RH snorkel refractory brickwork to a great extent depends on the accuracy and dimensional repeatability of bricks. In order to minimise the erosive influence of the flowing steel, the RH snorkel refractory lining should be executed in a manner which guarantees an intimate contact of individual shapes and whole rings

In order to obtain bricks with very tight dimensional tolerances, mechanical working is required. Multi-task stream grinder designed especially for the requirements of our products allows to dry shapes in stream with the accuracy of 0.1 mm. The grinder is also equipped with a rotary table that allows to grind whole rings composed from individual shapes. This device makes it also possible to mill out grooves and keys of any form on lateral cylindrical surfaces of machined ceramic rings.

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Impregnation process

maf-anov-rh-degasser-3One of the main mechanisms destroying magnesia-chrome refractories used in an RH device is corrosion caused by the infiltration of slag components inside the material. This corrosion combined with cyclic temperature variations results in the so called structural spalling.

During the operation, liquid slag penetrates inside the pores of the refractory material matrix and creates a compact layer with a certain thickness on the working face.

That corrosion may be restricted by decreasing the porosity and gas-permeability of bricks. In order to improve those properties, bricks after firing are made subject to an additional operation of impregnation.

That operation reduces the gas-permeability of bricks through the entire range of working temperatures.

Assembling of compound refractories

Proper designing and execution of the refractory lining of snorkels, especially in their critical areas, requires complex actions starting from the lining design, selection of the proper quality of its material, elaboration of an adequate method of its installation, precision of execution of its components, as well as accuracy of their installation in the thermal vessel.

That is why more and more frequently particularly responsible areas of refractory linings are fully executed at the manufacturer’s premises who is able to ensure required conditions of the technological process and achievement of expected operational parameters.

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maf-anov-rh-degasser-4Our company offers full RH snorkels supplied to the consumer as ready to be installed, large size refractory elements. Most important advantages resulting from their utilisation include:

  • shorter installation time which means more effective utilisation of thermal vessels;
  • high quality and repeatability of their useful properties resulting from the strict observation of the manufacturing process executed and supervised by adequately trained and experienced personnel;
  • lower refractory cost resulting from an optimum selection of qualities of materials for each zone of the product done by the manufacturer.