As the earliest company engaged in technology development and project construction of rotary kiln，ACRE has been leading the technology development trend of lime kiln.This paper introduces the technical difficulties and design difficulties of the 1 200 t/d self developed large scale active lime rotary kiln，this kiln type has the largest production capacity at present,and its main structure and control system are also comprehensively improved which have reached world advanced level.
There were challenges and opportunities for the lime industry in the year of 2018,and vigorously transformation and upgrading were carried out in this year,all kinds of gas-fired lime kilns have been greatly developed,among them the advantages of the kilns which fired with high calorific value gas were well known to all. This paper discusses the technologies of all kinds of gas-fired kiln,the recent trend of expending to low calorific value gas,and the problems involved in the reduction of the heat value of the gas.
The rotary kiln of active lime works with coal powder as fuel,which leads a circle shape dust liner inside the kiln.While the ring formation is getting worse and inside diameter of kiln is smaller,the factor of material filling is bigger,the thermodynamic engineering is damaged,the negative influence on the kiln comes for the output,quality and safety.Based on both analysis of active lime process and study of laboratory work,the paper gives the ring formation theory of rotary kiln with coal powder as fuel,and offers an efficient handling technology for the dust liner.
The sliding nozzle mechanism for ladle is developed for the improvement of steel-making technologies such as continuous billet casting and external refining and improvement of operation conditions of casting steel production.This paper introduced the features and improvements of FLOCON sliding nozzle mechanism.
When using mixed gas in Maerz kiln,by understanding the principle of the air-gas ratio,the proper equilibrium point of air-gas ratio will be determined to improve the comprehensive utilization of the kilns.
According to the characteristics of cord steelmaking and the requirements of working conditions,this paper introduces the requirements of the refractories used for steel ladles and analyzes the development history and present situation of refractories for the ladle of cord steelmaking.After comparing the advantages and disadvantages of the refractories currently being used,some new ideas and views on the use of refractories for the future are put forward.
The vertical compound crusher has the disadvantages of low crushing efficiency,hammer head easy abrasion,and high maintenance intensity efficiency.Through many technical demonstration and mine investigation,a new type and advanced crusher is put into use in the lime crushing production,and analysis and adjustment are taken on crushing efficiency,hammer head and operation maintenance.It is found that the production runs well and the crushing efficiency and the service life achieves the expected results.
This paper introduces the development situation of lime industry in 2018 and the technical characteristics and development trends of the rotary kiln,puts forward some solutions to the problems faced and predicts the development prospect in 2019.
This paper introduces the technical development status of mechanized lime shaft kiln with mixed fuel in 2018 and proposes improving measures for operation management and technical problems,and puts forward some thoughts and prospects for the optimization of industrial structure,upgrading of kiln equipment and green development.
Through the optimization on process operation,equipment improvement and equipment maintenance for the two internal crushing lines,the work efficiency is improved,stable supply of sintered flux products is ensured and production costs are reduced.
Aiming at the characteristics of low compressive strength of ordovician Majiagou limestone,easy to be pulverized in rotary kiln calcination process and seriously burst at low temperature,a new technology is explored to pretreat the ore,which reduces the bursting degree of ore in calcination process,improves calcination environment, realizes stable quality and increase production.
The traditional castables are prepared with calcined bauxite base material with simple particle size distribution,and filled with a lot of cement and water,resulting in larger accumulated voids.The penetration of liquid aluminium and electrolyte can not be well prevented during use.In addition,the bonding strength of high alumina cement-bonded castables is reduced due to the removal of a large amount of bonding water.When the temperature reaches between 900 ℃ and 1 100 ℃,most of the high aluminum cement bonding strength will be lost.By partly replacing the bauxite with silicon bricks and introducing water reducing agent and superfine powder into the matrix,the product performance can be effectively improved and the castables for aluminium reduction cell can be produced.The social effect and economic benefit are obvious.
In order to solve the problems,such as low temperature hydration of magnesia based refractory bricks,temperature and pressure fluctuations and partition control of hot air volume inside the heat treated furnace,we set two preparation rooms separately at the inlet and outlet of the furnace and some hot air circulation devices inside the furnace,and took partition control of hot air volume to ensure the required thermal condition.
Used magnesia carbon bricks are produced into regenerated materials.The samples of regenerated magnesia carbon bricks contains 20% regenerated materials.The structure analysis and component analysis are studied by polarizing microscope of Axioskop40,scanning electron microscopes of XL30TMP and energy dispersive X-ray of PHOENIX.The result shows that in high temperature,magnesia particles of the regenerated materials in magnesia carbon bricks are gradually eroded from the edge,fake particles are detected in regenerated magnesia carbon bricks,and anti-oxidants in used magnesia carbon bricks are whole oxidized or partial oxidized.
The granularity of lime for desulphurizer with KR method is controlled within the reasonable and economic range of 0.5 mm to 1.5 mm.Based on granularity requirement of the lime for desulphurizer with KR method,this paper introduces the preparations and their main features and usage suggestions with relaxation screen,air separation crusher and column mill as the main equipments.
Increasing scrap ratio can stabilize steel putout and reduce iron and steel smelting cost，but it is very unfavorable to converter lining.Through statistics and comparison of various technical and economic index data of converters in the well-known domestic steel mills A and B，the adverse effects of increasing scrap steel ratio on converter lining and the formation reasons are briefly analyzed.
This paper briefly introduces the main types and smelting process of the electric furnaces for steelmaking,analyses the wear mechanisms of refractories used by electric furnaces and summarizes the main types of refractories used in various parts of the electric furnaces.Then it emphatically describes the development and application of refractories for steelmaking electric furnaces and points out their main development direction.
Overburnt and accretion are common phenomenon during limestone in lime kilns.In this paper,the causes,treatment and prevention measures of accretion are comprehensively analyzed,which can effectively reduce the incidence of accretion.
This paper introduces a pressure stabilizer for heat treatment carburizing furnace.The problems of unstable furnace pressure, obvious deformation and local soft point in refractory die during carburizing process are basically solved.The aims of stabilizing the quality of the mould, improving the production efficiency and reducing the cost are achieved.
This paper studies the expansion joints setting,selection of filling material for expansion joints and PVC expansion joint plates fixing method.The results show that the reasonable expansion joints setting and expansion joint plates fixing are helpful to eliminate the hidden dangers,such as the materials peeling off causing by lacking sufficient expansion space during furnace oast,and are more beneficial to prolonging the service life of the furnace.
It is well known that the electric component would cause harmonic interference to electric grid.Frequency converter is a typical electric component.A number of high capacity motors controlled by frequency converter are used in double shaft kiln,which generate harmonic interference to busbars.To avoid the problem,a typical systematic diagram for power supply of double shaft kiln is established by ETAP software plus the function of harmonic analysis,which can help us get total voltage distortion rate of L.T.busbar and accurate frequency spectrums for different harmonic contents.
By using light-burnt forsterite,magnesite clinker and fused magnesite as main raw materials,phenolic resin as binder,magnesium-forsterite dry material was prepared,and the effect of addition of sodium tripolyphosphate on properties of the dry material was studied.The results showed that the addition of sodium tripolyphosphate could effectively improve the flexural strength and compressive strength of the dry material,and improve the slag resistance within a certain range.
ISSN 1673-7792 CN 21-1544/TQ Sponsor:ACRE Coking & Refractory Engineering Consulting Corporation,MCC Postal Code:8-29
