Technical features and prospects of lime rotary kiln
This paper reviewed the constructions of lime rotary kilns and technical progresses and features in 2013，and emphatically introduced the roasting system of 1 000t·d-1 rotary kiln.The major problems of the rotary kiln and corresponding solutions were also pointed out.The rotary kiln has good prospects for its mature technologies，good quality products and adaptable fuels.
The original design of three channels coal burner into Sinoswirl type dual-cyclone coal burner on the production line of active lime kiln is modified.The result shows that the dual\|cyclone coal burner has advantages of higher productivity and lower energy comsuption to a large extent with remarkable economic benefits.
Aiming to solve the problems of short service life of lining bricks and over heating of furnace shell due to poor insulation of lining bricks，we studied the refractory lining of the rotary kiln.Based on damage investigation and compounding tests，we developed a kind of composite percast brick with refractory working surface and monolith insulation，by which service life can be extended by over two years and surface temperature of the furnace shell can be reduced by more than 50℃.
This paper studies a silica brick sample removed from the heating wall in coking chamber of a 40\|year\|old coke oven during hot repair.The result shows that the silica brick still remians dense and uniform for over forty years，with no strength degrade.In application of the silica brick，the carbon in coal can penetrate into the pores of the silica brick and make it “silica carbon brick”,containing about 5% canbon，which benefits to improve the performance of silica brick and increase the heat transfer efficiency of coking.Unavoidably，the carbonization face is corroded by ash in the coal.However，the low corrosion rate and poor penetrability of this brick can not damage the silica brick.
This article introduces a synergistic practice，including improvement maintenance,equipment technical modification,products structure adjustment and system building for equipment periodical repair to modify the eight shaft kilns on half\|off production.The result shows that obvious effects have been obtained，such as better kiln conditions and thermal insulation，higher productivity and lower fuel consumption and manufacturing cost as well.At present，a stable profitability has been achieved.
This paper analyzes the main problems in production of No.1 and No.2 Maerz lime kilns of Liusteel and describes the design optimization of No.3 lime Maerz kiln.The optimized kiln can increase productivity and produce metallurgical lime of superior quality.
This paper studies the aluminium carbide，a recognized harmful substance formed in preparation of magnesia carbon bricks or regenerated magnesia carbon bricks.The formation mechanism of aluminium carbide is determined within the range of thermal treated temperatures.The paper also studies the effects of thermal treated temperatures and graphite additions on the formation of aluminium carbide（Al4C3）.
Crucial technology and development direction of shafe lime kiln with mixing fuel
This paper reviewed the construction situation, technical progress and features of crucial technology of the shafe lime kiln with mixing fuel,and propoesd technical choices for kiln construction and major measures for high quality,low cost and high production.
This paper analyzed the cause of viscous slag formation of walking beam and column in hot rolling furnace，which mainly results form the low refractoriness under load（RUL）and large deformation. Based on analysis of erosion structure，the dissolution of alumina into bonding slag phases of furnace lining increases the slag viscidity，which may give rise to seriously hang slag and hinder normal production. Among refractory control standards，RUL and other parameters to control the quality of furnace lining are not stipulated.
The new No.4 Maerz kiln has produced qualified dolomite with LDG as fuel under innovated technologies.In view of brittleness of dolomite，the productivity of No.4 Maerz kiln and each control coefficient in production，a reasonable operating system is produced for stable products quality.
In metallurgical industry，sliding nozzle becomes more and more important as a critical equipment in continuous casting process.However，the cracks interrupts continuous use of the sliding plate.This paper analyzed the formation and harmful aspects of the cracks and proposed a solution to minimize the cracks.These improvements raise the service life of the sliding plate.
Innovation on metallic hose of spray gun in Maerz kiln
In view of the phenomenon of gas leakage in production of Maerz kiln in roast plant，this paper analyzed the major causes of sand holes and cracks on metallic hose and introduced a repalcement of the metallic hose by ripple compensator fixed with hard tubes which is proved more stable and safer in production.
Influence of calcining process on activities of three kinds of limestones was studied through by calcining test and scanning electronic microscope.The result shows that the major factors affecting the activity of light-burned lime includied calcining temperature,soaking time,particle size and microstructure of raw material.
In view of environment polution and resources reusing of iron tailing，this paper proposed a method of synthetized forsterite refractory by adding caustic-burned magnesia powder into the iron tailing.In laboratory, two kinds of synthetic aggregates are prepared with different proportions and determined by DSC method.The result shows this new refractory has higher specific heat value and larger capacity for heat storage.
The longevity methods of ladle sliding plates were proposed from choice of materials，slide volume，slide shape and sliding machine，etc．The slip rate of the improved sliding plat reaches 100%，the service life of the improved sliding plat reaches 4 heats and basically meets the requirements of the production.
This paper discussed the pioneering, guiding and guaranteeing effects of patent information on enterprise technical innovation.Taking patent informations of refractory free chrome for RH furnace refinement as example，the patent information combined its advantages with technical innovation and transformed technical innovation into productivity to maximize the economic benefit.
To increase yield and performance indicators and decrease product energy consumption,the key parts and equipment in production of silica bricks which can easily effect product performances and yield were studied.Furthermore,with reference to domestic and international advanced technologies,the raw materical iron\|removal process and automatic added system for additives and mineralizers were developed and a best technical program was determined for the production of high quality silica bricks to optimize product quality and minimize the energy consumption.
The production process of iron magnesium dolomite is simple.Iron magnesium dolomite has two high-melting-points solid phases—solid solution periclase（MgOss）and free clacium oxide（fCaO）,so it has the characteristics of MgO-CaO refractories.With excellent comprehensive performance,the iron magnesium dolomite syntheticsand has high durability in application of dry play material，gun-mix refractory,coating and insulation castable refractory furnace charge.
To explore the usability of vanadium iron smelting furnace slag for refractory alumina,this paper introduces a physical chemistry experiment with an unbroken alumina slag cake.The result shows that the major constituents of the alumina slag are Al2O3,MgO and CaO，and the major compositions are spinel and calcium aluminate；its refractoriness is over 1 790 ℃，the bulk density is higher than 3.0g·cm-3，the water absorption is 3.0%.Alumina slag can be uesd to replace high alumina cement for its hydraulicity.Its particle strength is similar with flint,so it can be used as refractory aggregate.In conclusion，the alumina slag can be used for refractory material.
To solve the problems of production process in Maerz kiln of Liusteel，the major technologies such as reversible belt at crown,connection mode of spraygun tube,suspension cylinder castables and spraygun materical were improved.After that,the down time of equipments in the kiln is greatly shortened and the production is significantly increased.
BASK of Xing steel was put into operation in Februry 2005，and overhauled in June 2008.The first kiln was used for 3.42 years.Compared with the first，the second kiln has been significantly improved and lasted for 5.41 years till December 2013.The paper analyzed the production process of the second BASK and proposed several control measures for prolonging furnace life as a reference for future BASK production.
During the process of lime calcination in rotary kiln，lime quality and output depend on the ratio of coal powder and raw matericals，as well as the equipment selection and assembly，which directly affect the company’s econmic benefit.This paper analyzes how to maximize the output and lime quality of rotary kiln by stablizing thermal regulation，reasonably adjusting coal-air ratio under the existing equipment conditions without major modification or replacement.
This paper introduces the digestion mechanism,digestion process of calcium hydroxide and its technical characteristics,and analyzes the quality indexes of calcium hydroxide.The result shows that the calcium hydroxide produced by dry process has advantages of high quality indexes,good production environment and simple process and so on.
This article mainly introduced the importance of silica brick crater and iron plaque in silica brick inspection, and then analyze the cause of formation of some of the silica brick melt holes in the process of production,such as iron hole,calcium hole，so preventive measures should be taken.
By analysing phase diagram，the raw matericals，such as corundum，α-Al2O3 micro powder，spinel and fused magnesia and sol or/and brine composite binder for unburned carbon\|free alumina\|magnesia spinel brick were determined in this paper.The effects of different amounts of spinel powder，fused magnesia，chemical magnesia，α-Al2O3 micro powder，Cr2O3 fine powder and SiO2 micro powder on performance of carbon\|free alumina\|magnesia spinel brick were observed.
In this paper,according to operation principles of the preheater feeding room,a finite element model of different structural style feeding room was built.On the simulation analysis of heat transfer field of different structural style feeding room based on computational fluid dynamics software Fluent,the distribution of velocity field and temperature field in feeding room was obtained.And the influences on the velocity field and temperature field of the feeding room structure were analyzed.
This article introduces a method of quickly replacing spray gun in Maerz kiln and analyses the burnt-loss reasons of the spray gun，moreover proposes suggestions to improve the life.
To supply the superfluous lime after crushing for sintering,Liuzhou Steel Iron ＆ Steel Co. constructed a new production line of lime crushing in lime warehouse.The processing set\|up,conditions of construction,technical parameters and effection of lime crushing production line were introduced.
In order to save energy, reduce consumption and control cost, reformation of transmission gear, valve and gas pipeline of friction press was carried out to solve the problems of low efficiency of energy and air leakage in molding of silica brick. Meanwhile, reformation of ejection gun of nature gas nozzle and spinning disk in tunnel kiln for firing silica bricks was also carried out to reduce the production cost and firing cost.
This paper introduced the mixed charging process and configuration of the energy-saving lime shaft kiln in detail.Technical reconstruction improved the product quality and reduced staff for greater efficiency and higher productivity.
Porous cordierite was prepared with powder of light-burned magnesia，waste nozzle and silica fume as raw materials.The paper analyzed the effects of magnesium oxide on bulk density,crystialline composition and microstructure of the porous cordierite，which were characterized by XRD and SEM.The result shows that the porous cordierite material with cordierite as major crystal phase can be prepared by high\|temperature solid\|phase sintering method.But excessive addition of light\|burned magnesite will reduce the porosity and increase the boltonite phase.
This paper introduces the optimization of mechanical level probes which was often trapped in lifting，causing frequent shut down of the roasting plant of Maerz kiln in SISG.It was proved that after optimization，the mechanical level probes can be lifted smoothly，providing good conditions for safe and stable production of the kiln.
ISSN 1673-7792 CN 21-1544/TQ Sponsor:ACRE Coking & Refractory Engineering Consulting Corporation,MCC Postal Code:8-29
