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Technical Report No.47 (2004)

Shinagawa Technical Report
No.47 (2004)

CONTENTS

Preface

Past, Present, Future

Senior Managing Director Hideaki NISHIO

Special Theme

Torpedo Ladle Refractory Improvements and Future Developments

BlueScope Steel Limited Len WOODS , Jim MATTHEWS , Ross STEWART

Abstract

BlueScope Steel operates a 5.2 million tonne per annum integrated plant at Port Kembla,NSW Australia.

The Port Kembla plant runs a fleet of 38 torpedo ladles to carry liquid iron from two blast furnaces to the steelmaking shop.

Torpedo ladle refractory life has improved over the past ten years by over 250%.

This paper describes the changes in refractory materials, installation, and fleet management that have produced this improvement.

Further planned changes are also described that will lead to future improvements in torpedo ladle refractory life and cost.

Evaluation of Alumina Corrosion Rate Using Rotating Cylinder Method
(Effect of Slag Composition and Temperature)

JFE Steel Corporation Makoto IIYAMA

Abstract

An alumina rotating cylinder test was performed with CaO-SiO2-Al2O3 system slags with different compositions and temperatures,confirming the possibility of a theoretical estimation ofthe effect of the slag composition and temperature on the corrosion rate based on the difference in the alumina concentration in the saturated slag and bulk slag, slag viscosity, and ion diffusion coefficient.

However, an investigation of the ion diffusion mechanism is necessary in order to improve the analytical accuracy and expand the scope of application of this method.

Steelmaking Refractory Trends in Japan

Shinagawa Refractories Co., Ltd. Hideaki NISHlO

Abstract

During the past 1O years, under Japan's faltering economy, the steelmaking industry has consolidated its production system in order to enhance international competitiveness and to increase profitability.

At the same time the shift to high grade steel and special steel has been accelerated.

In order to cope with the needs of the steel industry, refractory makers have made serious efforts not only to improve durability, reliability and workability of refractories but also to reduce refractory costs.

Ecologically friendly refractories have been developed recently.

The changes in these past 10 years and the latest trends in production of refractories and steelmaking refractories including functional refractories for continuous casting are described.

Articles on Refractories for Nonferrous Metals, Glass , Cement and Ash Melting

Present Situation and Future Trends of Refractories for Nonferrous Metals

Yukinobu KURASHINA , Kenichi MATSUBARA and Shingo FUJITANI

Abstract

Magnesia-chrome brick is mainly used for copper smelting furnaces among nonferrous metals.

Brick damage is caused by structural spalling, penetration of copper and slag in addition to slag erosion.

We have developed fine texture and low permeability magnesia-chrome bricks to prevent penetration, and they are being used at many plants at present.

In aluminum furnaces,refractories such as high alumina bricks, castables and plastics are used.

The refining tempera-ture is low and slag erosion is little, however, metal penetrates into the bricks and the brick quality deteriorates.

Therefore, bricks or castables with reduced metal reaction properties and good separating properties owing to the use of additives are used.

Present Situation and Future Trends of Glass Industry Refractories

Yukinobu KURASHINA , Keiji SAIT0H and Shingo FUJITANI

Abstract

At present, various kinds of refractories, such as fused-cast bricks and burned bricks,have been the main refractories for glass furnace.

Among burned bricks, silica bricks, alumina-zircon bricks and so on are used for glass furnace smelter lining, which does not contact glass.

For the glass furnace regenerator sidewall and checker bricks, magnesia, spinel, high alumina and fireclay bricks are used.

Recently, magnesia-chrome brick application is decreasing due to environmental demands.

Chimney checker bricks are increasing because of high heat transfer efficiency.

Efficiency is changedwith flue size and brick thickness.

It is important to select suitable checker designs in accordance with furnace structure and operating condition。

Present Situation and Future Aspects of Cement Rotary Kiln Bricks

Eishi IIDA , Keiji SAIT0H , Tamiatsu K0YAKE and Hironobu HARA

Abstract

Chrome-free bricks, replaceable to magnesia-chrome bricks in the high temperature burning zone in cement rotary kilns, are one of the key technologies to satisfy the worldwide ecological demand.

It is also important to improve magnesia-spinel bricks for the transition zone and the cooling zone to meet the change of wear factors.

In this paper, such current subjects and our idea for the solution are discussed.

Refractories for Ash Melting Furnaces

Yukitoshi KUB0TA , Eishi IIDA , Kenichi MATSUBARA and Toshihiro YAMAM0T0

Abstract

Recently, the ash melting furnace has become important for the waste disposal technology from the viewpoint of environmental protection.

SiC, C-SiC, Al2O3-Cr2O3 and MgO-Cr2O3 refractories are usually used for these furnaces according to individual furnace operating conditions.

The features of these refractories for various types of ash melting furnaces are summarized and newly developed chrome-free refractories are introduced in this report.

Chrome-free refractories utilizing specially prepared spinel raw materials show almost the same or even better slag erosion resistance than conventional chrome containing refractories.

The application and improvement of these chrome-free refractories will be the important subject for future waste melting furnace technology from ecological and environmental aspects。

“SUBMAX ”Refractories for Nonferrous Metal Casting

Ryuichi HOSAKA , Yuichi TAKAKURA and Tatsuo TAKAGI


Articles on Refractories for Iron & Steel

Suppression of Heat Loss from Molten Steel Surface in Mold through Continuous Casting Nozzle and Mold Powder

Masanori OGATA , Tomoaki OM0T0 , Shinsuke IN0UE , Yukimasa IWAM0TO and Taku KlTAMURA

Abstract

Heat loss from the molten steel surface in the mold to atmosphere through SEN and mold powder affects the steel quality and operating efficiency in continuous casting.

Low thermal conductivity AG material, carbon-free inside liner, and fiber-free thermal insulation material can be employed to suppress heat loss through the SEN.

This effect is confirmed by low SEN temperature during casting.

As for mold powder, powder layer thickness, slag viscosity, grain shape, exothermic and endothermic reaction, and consumption rate affect the thermal insulationproperty.

PRIOS, an ultra-high viscosity mold powder, is especially effective in preventing theheat loss.

Thermal Properties of Submerged Entry Nozzle (SEN) Materials

0samu N0MURA and Shigeki UCHIDA

Abstract

Transient heat transfer analysis by FEM was done using actual operating data of special grade steel and a single material SEN model with approximate theoretical density.

At casting start, the variance in hot face temperature was large and the hot face temperature was lowest at the bottom of the portless side, especially for graphite.

The rate at which the hot face temperature rose was highest for ZrO2 and lowest for graphite.

The molten steel temperature drop was much greater because of the large quantity of heat taken from and stored in the SEN.

ZrO2 is a material capable of storing heat near the hot face.

Graphite is a material capable of quickly transferring and largely radiating heat.

At casting end, the heat quantity stored was very small and that radiated was large.

The molten steel temperature drop was much smaller than at casting start.

The thermal properties of an optimum material which will prevent alumina clogging and reduce molten steel temperature drop are presented.

Development of Shot Creating Materials with Ultra Short Curing Time

Kazushi MARUYAMA , Masatsugu KlTAMURA , Kiyoyuki K0MATSUBARA and Takashi IIDA

Abstract

Powder or slurry agent has been generally used as a coagulator for short curing time Shot Create, but there is a problem of uneven dispersion with the powder coagulator system and a problem of workability with the slurry coagulator system.

As a solution to these problems, we used a liquid binder which was superior to gunning mixes in dispersion uniformity and storage stability, as a coagulator.

We found that the cement hardening reaction could be accelerated by using some specific combinations of liquid coagulator and dispersant for premixed castable and developed ultra short hardening time Clean Shot (CLS) system.

Blast Furnace Repair Technique

Yukitoshi KUB0TA , Masatsugu KlTAMURA and Junichiro OKUHARA

Abstract

Highly reliable blast furnace repair technique has been strongly demanded for longer service life and more stable blast furnace operation.

We have applied the newly developed Clean Shot (CLS) system to the blast furnace shaft repair which achieved higher durability, shorter installation time and less dust and rebound loss than conventional dry gunning repair system.

We also developed new injection mixes for blast furnace repair from outside including fast hardening injection mixes for upper blast furnace repair and resin-bonded injection mixes for blast furnace bottom which can be installed by convenient equipment.

MgO-C Plate and Upper Nozzle for Continuous Casting

Yuji YOSHIMURA and Nobuhiko IMAI

 

Newly Developed Slide Gate Valve Equipment

Kenji MITSUl and Mototsugu OSADA


Technical Information on New Products of Associate Companies

Paste Type Desiccant "PT-DESICCANT-No.29"

Takashi YAMAMURA , Katsuhiro WAKASUGI and Katsuhiko FUSE

 

Cristobalite for Dental Investmen

Hikaru KATAYAM

 

Inorganic Paints and Adhesives

Kazuki IGAMI

 

Magnesia Stabilized Zirconia Ceramics

Akira SHIRANlTA and Terumitsu ICHIM0RI