The factors that affect the service life of the ladle bottom are found by analyzing the working environment of 150t ladle of Tianjin pipe corporation，and some technical improvements are made.The service life of ladle bottom impact area are improved from choice the materials of magnesite\|alumina spinel carbon bricks,improve the laying methods of the ladle bottom impact area,strengthen the maintenance of ladle and change the size of the brick etc.,the safety of ladle and lower consumption are gained.
This paper briefly introduces the status and composition of Al2O3-SiC-C based castables and analyzes the chief factors on iron runner lining damage with the material of Al2O3-SiC-C based castables,and systematically summarizes the improvements and research developments of the performances of Al2O3-SiC-C based castables.
In this paper, four different commercially available sources of α-Al2O3 powder which were marked as domestic A,domestic B,import A,import B,were added into low cement castables quality bauxite.The experimental results showed that,Al2O3 powder of import A has bimodal distribution and fine particles,so it fills better and helps the system sintered well;the sample containing import A powder has the best performance;the sample containing domestic B powder has wider distribution of particle size and larger particles,so it has the worst performance;the sample containing domestic A powder has narrow distribution of particle size,and its performance index is second only to importing A powder.
Building the heat transmission model of single gunning particle by the analysis of heat transmission of mullite ceramic welding,calculating the melting time of different gunning particle by means of stable heat transmission formula.It is an important theoretical basis of the particle proportioning and operating instruction for mullite ceramic welding.
Compared with the consumption indexes of No.1 to No.3 Mearz kilns,this paper analyzes the reasons of high LDG consumption of No.4 and No.5 kilns and takes corresponding measures to reduce the gas consumption by optimizing technical operation and improving equipment.
Metallurgical materials technology company of lianyuan steel have four Maerz kilns (400t·d-1,450t·d-1,and two 600t·d-1 kilns).Refractory bricks caused by non\|standard connection channel refractory drop seriously in kiln No.2 and kiln No.3,there are even burn through the phenomenon of kiln shell.Through the early stage of the relatively simple in the original upper arch add castable solutions to drop the lighter brick of kiln No.3,but the kiln No.3 burned through phenomenon again two months later,so you need to find a complete repair of rapid repair.
To meet the national emission standards for environmental protection, a technical design for de\|duster installation in mechanical lime shaft kiln provides de-dusting technical parameters after comparing two kinds of filter materials and proposes higher requirements for structural design and electric control of the kiln.
Steelmaking production has certain requirements for limestone particle size, and some correlative experiments need to be done to choose the appropriate limestone mines for raw materials.At present, there is no valid experiment method for the measurement of lime pulverization rate.Based on the analysis of pulverization mechanism of lime in rotary kiln, a simulation method for the measurement of lime rotary kiln pulverization rate in laboratory is determined.This method does not need to prepare a lot of experimental raw materials and just need simple equipment, and the experimental data is close to actual production data, which is worth popularization and application.
This paper studies on the relationship between ladle filler sand and the ladle self-starting pouring.Deeply analyzes from quality,property,adding status of ladle filler sand,and operating status of ladle.The analysis result shows the ratio of ladle self-starting pouring relates to the quality,particle shape & size,thermal conductivity,coefficient of thermal expansion,molten steel penetration resistance of ladle filler sand, status and operation cycling time of ladle,stirred mode of molten steel.We need to choose different type of ladle filler sand based on different ladle application environment.
At present,double shaft kiln is an advanced lime kiln technology with high automation and strict process control requirements in China.The development of the control system is an important part in technology of double shaft kiln.Siemens PLC platform is a widely applicable control system development platform.Based on it,the control system of the double shaft kiln is successfully developed,which can template the design and application system and provide support for scale development and optimization of the control system.
Anchors serve to strengthen the role of robustness in monolithic refractories,so its performance has a direct impact on the effect of the use of monolithic refractories.Overall lining nickel-iron anchor kiln used for U-,Y-,V-,double R-type or anchor bricks.After using the appropriate anchor lining integrity,long kiln life,high capacity,low cost.
During the heating-up process,the low temperature heating-up apparatus has some problems,including wide flame fluctuations,easliy be blown-out by combustion air and unstably control on kiln temperature. Based on that,a design improvement on nozzle develops a set of heating-up apparatus with simple structure,high automation and continuous low temperature workability.
Based on technological requirements for the preparation of ceramic welding repair materials，through the careful selections for refractory raw material of high alumina ceramic as well as its grain size distribution and scientific calculation on fuel quantity，a more proper composition is determined by visual inspection and physical and chemical indexes with less welding repair tests，the performance indexes of the welding repair product are close to or above the original high alumina brick which can meet the technical requirements of practical application.
To prevent molten steel of the steel ladle nozzle from freezing,stuffing sand need to be filled in the nozzle.It is known that the main factors to affect the automatic open ratio of stuffing sand are the material and particle sizes of stuffing sand and continuous casting technique as well as the filling effect of the stuffing sand.This paper introduces several filling modes of stuffing sand and then compares them with each other.
In the design of new type of 7.63m large coke oven and top combustion hot blast stove, a lot of molding difficult special shape bricks are required, which brings great difficulties to production and quality management. Because the original production process has been unable to meet the needs of the production and quality management, so a new production process of raw materials is developed to guarantee the good plasticity of raw materials to be shaped and meet the requirements of production and prepare products with high compressive strength and low porosity.
Light-weight silica bricks were prepared with waste silica brick clinker with the critical particle sizes of 1.65mm, 2.18mm and 3～5mm. The effect of different critical particle sizes on the composition, appearance and performances of light-weight silica bricks was studied, and the critical particle size of the silica brick clinker required for preparation of the best light-weight silica bricks was determined.
This paper introduces a new technology of waste heat utilization for tail gas of lime rotary kiln by flue gas\|soft water thermal tubular exchanger,and concludes that the technology can not only make the most of waste heat of tail gas,save energy,reduce consumption and protect environment,but also can bring considerable economic benefit.
With low calories and low temperature,the waste heat of the heat transfer oil in beam shaft kiln was easy to overlook.Based on thermal analysis and waste heat analysis of the heat transfer oil,the article proposed a comprehensive utilization program of the waste heat of heat transfer oil and waste gas,which had the features such as low invest,high return,simple operation,energy saving and emission reduction.
For radiation heat untilization of lime rotary kiln tube, this paper introduces a technical program of recycling radiation heat by designing gathering heat cover and waste heat untilization methods of heating,bathing and power generation in lime production area. Based on the calculation of recycle heat and investment cost,it is found that the project is suitable for promotion and application with the advantages of short payback period and high return benefit.
This paper introduces the measures of optimizing the process operation and ensuring stable operation of the equipment to reduce the rate of immature and overcalcined lime of No.4 and No.5 Maerz kilns at the condition of low gas value.
This paper studies the effects of salt-soaking on properties of Cr2O3-Al2O3-ZrO2 bricks for coal water slurry pressurized gasifier, especially the influence on erosion resistance and penetration resistance. The result shows that the erosion resistance and penetration resistance of Cr2O3-Al2O3-ZrO2 bricks after salt-soaking is better than before.
Based on effects of lime grain size and temperature of slaking water on slaking time during the lime slaking process,the process equipment of calcium hydroxide was improved and optimized for energy saving, emission and production cost reduction.
According to the initial conditions of local raw coal and the requirements for limestone calcination and capacities of 5 lime kilns of 600t·d-1,a lime production line with the annual output of 1 million tons are equipped with a pulverized coal preparation system. Aiming at the problems of pulverized coal preparation system before,some improvement measures are present in the design process and finally verified by actual production.
For the realization of production and standard of coal-fired double shaft kiln，this paper introduces some technical measures including the control of limestone raw materials,coal-fired system and burning process and the introduction of BIM technique into the practice of lime engineering.
This paper introduces the basic parameters of gas-fired lime rotary kiln and the characters of metallurgical coal gas being used here，proposes the principle and importance of the optimization on gas proportion with different calorific values，and optimizes the best gas proportion in practice.
This paper briefly introduces the design,material selection and optimization of castable and refractory bricks which used on four active lime rotary kilns with the capacity of 1 000t·d-1,and recommends a new building plan for large lime rotary kiln through some tests and applications.
CaZrO3 compound was prepared by sintering Ca(OH)2 and desilicon zirconium/monoclinic zirconia with 1∶1 molar ratio.Then the paper studied the effects of ZrO2 variety on the CaZrO3 compound.The results show that more pure monoclinic zirconia helps CaZrO3 to be compounded.
This paper analyses the cracks problem of composite slide plate molding by two kinds of materials with different performances and proposes the solutions for reducing the cracks. It is known that the optimization of feeding method in composite slide plate molding can improve the quality of slide plate.
This paper analyzes the reasons for black core in silica brick in the firing process of tunnel kiln and proposes corresponding solutions on that basis.Tests revealed that the K value and M value tend to be reasonable by improving the loading methods and kiln car,and the temperature differences are narrowed and the black cores are eliminated to reduce energy consumption and save production cost for positive effects.
Effects of CaO content on properties of magnesia-dolomite system refractories
This paper compares the properties of magnesia-dolomite system refractories with different contents of CaO.It is concluded that with the increase of CaO content in samples,the hydration resistance reduces gradually,when the CaO content is below 20%,the samples have good hydration resistance,when the CaO content reaches 56.9%,the hydration resistance drops evidently,and the samples will not be used any more.
Design and optimization for tundish retaining wall
Rational design for tundish retaining wall was used to optimize tundish flow field,uniform tundish temperatures, accelerate accumulation and floatation of the inclusion,and improve cleanliness of molten steel in tundish.
This paper introduced an automatic venting device for molding of shaped products.The device for improved the quality of the exhaust gas in molding process and efficiently eliminated the layer cracks,ultimately guarated the product quality and increased the production efficiency as well as reduced the production cost.
Analysis and solving methods for causes of ringing in gas-burning lime rotary kiln
The ringing period of gas-burning lime rotary kiln is about half a year，this paper analyzed the causes of ringing formation to reduce cost and improve product quality.The reasons of ringing were as follows，firstly inclusions in coke oven gas and converter gas probably contained some chemical compositions which could form low melting point oxides with CaO，secondly raw materials contained clay，thirdly feeding rate was improper.For the reasons above，some solving methods were put forward，such as strengthening inspection and management of raw materials，treating fuel gas before use and optimizing operation process and so and.
According to the requirements of control process of environmental desulfurized limestone powder processing system, the automation control of milling system is realized by using S7-300, Profibu-DP bus communication, frequency control and remote video monitoring technology, and increases the accuracy of materials charging,powder selecting and qualified rate of limestone powder.
Double hearth lime kiln with its low heat consumption,the characteristics of high lime quality is widely used in the metallurgy industry and domestic,but in the long\|term production,double hearth lime kiln waste gas has been letted out, the temperature of the waste gas is low, and did not arouse enough attention, then has not been recycled.This paper focus on this part of the heat recycling.
It is difficult to treat the blockage of coal injection pipe and nozzle,which consumes huge labour power and material resources and seriously affect the stable operation.Therefore,it is necessary to look for a simple treatment in stable operation of the beam lime kiln.
This paper analyzes the development of lime rotary kiln in 2014, defines the main assessment indexes for the technologies of large lime rotary kiln and proposes new technologies and main problems of the lime rotary kiln in 2014. Finally, the paper prospects the technical development of lime rotary kiln for 2015.
This paper introduces the status of shaft lime kiln with mixing fuel, chiefly analyses the direction of technology innovation and ascertains that innovation on increasing ore utilization ratio, saving energy and optimizing operation will be the direction of technology innovation for low\|cost production, and further proposes the basic thought on how to increase production efficiency and lower costs for shaft lime kiln with mixing fuel.
This paper studies the blast heater refractory erosion caused by HCl in blast furnace gas. It is found that in clay bricks, HCl gas can promote the transformation from silicate glass phase and recessive aluminum silicate into mullite and cristobalite and in silica bricks, HCl gas also can promote the transformation from cristobalite into tridymite,however obviously decreases the degree of crystallinity of the particles and leads to cracks because of the irregular expansion of the particles.
Rim usually appears in production of calcined lime in coal type rotary kiln of active lime, temperature change and rim falling\|off in the process of rim treatment can damage the refractory, which require high strength and thermal shock resistance.The selection of refractory relates to the proper running of rotary kiln.
Adding Cr2O3 (0,1%,2% and 4%,in mass) to the experimental basic formulation of steel-tapping hole filling refractory, the effects of different Cr2O3 contents were discussed.The results show that the corrosion resistance increased obviously when Cr2O3 was added, and the bulk density and strength reduced a little.When Cr2O3 addition is 2％, the best comprehensive property was obtained.
Refractory construction process is the forming process of RH furnace project entity and the important stage of the formation of final refining furnace. So, the quality control of RH furnace construction stage is the key point of the quality control in the whole project. This paper mainly analyzes the quality control in construction stage of RH furnace and proposes some opinions on strengthening quality control of the construction stage.
This paper discussed the status of limestone, fuel and demands for lime products of Chongqing Steel Group and studied the lime production technology at home and abroad.By establishing the three layers fuzzy comprehensive evaluation system for the active lime system and based on analysis of experts and managers,technology selection of active lime project was finally determined.
Experiments have been done to produce light weight silica bricks by adding arthracite duff，composite ignition loss agent XW and coke fines respectively as ignition loss agent into waste silica brick chamotto.On comparative analysis of the experimental results，an optimal ignition loss agent is chosen，which can obviously reduce the lacking edges and improve the appearance of the fired brick.
This paper analyzes the failure mechanism of the lining of lime shaft kiln with coke as fuel and selects proper bricks as kiln lining. It is found that the lining life can be prolonged by reasonable masonry methods which can meet the normal demand of steel-making and also improve the economic benefits.
ISSN 1673-7792 CN 21-1544/TQ Sponsor:ACRE Coking & Refractory Engineering Consulting Corporation,MCC Postal Code:8-29
