Application Prospect of 3D Printing Technology in Refractory Precast Components

3D printing is a rapid prototyping technology to shape materials or objects through printing layer by layer driven by digital models, which can be adopted for the manufacture of refractory precast components. Thus, the production technology of refractory precast components as well as the technique and advantages of 3D printing was introduced. The feasibility and application prospect of 3D printing concrete, contour crafting and adhesive 3D printing in refractory precast components were presented.

Application of Digital Analysis Technology in Refractory Petrographic Analysis

Six specimens of fused cast AZS 33#material were taken as samples,and their chemical compositions and physical properties（ initial separating temperature o glass phase,corrosion amount in 24 h,glass phase seepage,and bulk density） were tested; low powered backscattered electron images of the samples（ three for each sample） were taken by a scanning electronic microscope with a reinforced backscattering probe. Then,firstly,the images were processed,and the phase compositions（relative contents of pores,matrix,alumina- zirconia eutectoid and primary baddeleyite） of the samples were obtained by counting. Secondly,the correlation coefficients of all parameters were calculated; indistinctive coefficients and unimportant variables were eliminated by F- test. Thirdly,the roadmap of the parameters was established and explained according to professiona knowledge.

Development Trend of China’s Refractory Industry in the New Era

The development status of the downstream industries of refractory industry,such as iron&steel,cement,glass,and nonferrous metals was analyzed,and it was pointed out that the market demand of refractory industry entered a platform period.Effect of supply-side reform on the development of refractory industry was deeply discussed,the viewpoints of multi-dimensional innovation of refractory industry were put forward,and the development trend of automation and intelligence in refractory industry was emphasized.It was clarified that the“Belt and Road Initiative”brought new opportunities and pointed out the development direction of China’s refractory industry.

Progress of Environment-friendly Basic Refractories for Cement Industry

The chrome pollution from cement industry was introduced briefly,the research on chrome free basic refractories for cement kilns was reviewed,the production technologies of magnesia calcia,magnesium aluminate spinel,magnesia hercynite refractories,etc. were specified,the principles to improve thermal shock resistance and coating adhesiveness of refractories were analyzed,the measures to extend service life by improving production equipment and service conditions of refractories were put forward,the future of chrome free refractories was expected and some developing suggestions were given.

Corrosion of Disposing Urban Domestic Wastes on Refractories for Cement Rotary Kilns

Corrosion of burning urban domestic wastes to alkali-resistant bricks and spalling-resistant high alumina bricks was researched by static crucible method and SEM in order to choose refractories for cement rotary kilns for collaboratively disposing wastes. The result indicates that the main corrosion mechanism is slag permeation and corrosion ; the emitted high temperature gases containing alkali, sulfur and chlorine during burning the wastes re- act with refractories forming low melting point sulfate, chloride and compound salts, which metamorphose the refractories, and the loose metamorphic layer is easy to spall under thermal stress. So, corrosion resistance and spaUing resistance shall be taken into account when choosing refractories for cement rotary kilns for collaboratively disposing wastes. It is suggested that decomposition furnaces should adopt spaUing resistant high alumina bricks and anti-coating SiC castables, and preheating equipment should adopt high strength alkali-resistant bricks and castables.

Review on Modeling and Optimization for Refractories

This paper introduced characteristics of refractories and step of simulation. During simulation,firstly analyzed mechanism of technology; secondly described the mechanism as quadratic equation; thirdly designed and executed experiment; later made regression equation and optimization; then found technical conflict; finally analyzed and resolved the conflict. Doing repeatedly like this,resolved difficult problems.

Research on Synthetic Forsterite with Magnesite Tailings

High purity forsterite was prepared with magnesite tailings and quartz pounder as starting materials. The influence of the preparution process on the physical properties of the synthetic forsterite was studied. The ph,se composition and the microstructure of the synthetic forsterite were analyzed by means of XRD and SEM. The results ,show thal the composites with 63% MgO fired at 1 670℃ exhibit the highest compact structure.

Corrosion of Basic Refractories for Glass Tanks Using Petrol Coke and Countermeasures

Replacing heavy oil with petrol coke can greatly reduce the cost of glass production,but obviously shorten the service life of refractories used in the regenerator checker body of glass tanks.To prolong the service life of the regenerator checker body,the slag chemical composition and alkali-sulfur ratio of glass tanks after using petrol coke and the damage mechanism of the residual magnesia bricks in the regenerator checker body were studied,as well as the corrosion resistance of three magnesia based bricks(direct bonded magnesia chrome bricks,fused rebonded magnesia chrome bricks,and fused rebonded high-purity magnesium aluminate spinel bricks).On this basis,a series of targeted countermeasures were adopted to optimize the configuration of refractories,significantly improving the service life of checker bricks and meeting the requirements of glass industry development.

Impact of Bauxite on Performance and Structure of SiC-mullite Brick

SiC- mullite brick is widely used in the upper and lower transitional zones of cement rotary kilns, due to excellent thermal shock resistance, and abrasion resist- ance. The investigation of different bauxites was made on the performance and micro-structure of SiC - mullite brick, especially thermal shock resistance. In two batches of bricks （ G1 and G2 ） , and two grades of bauxites （ L1 and I_2 ）, samples＇ physical and chemical properties were tested, and microstructure and phase composition were studied by SEM and XRD. The results show that raw material I2, containing large numbers of micro- pores smaller than 4 μm, has well developed mullite phase. While using L2 as aggregates and flues, SiC- mullite brick G2 has excellent thermal shock resistance. Therefore, for manufacture of SiC - mullite brick, not only chemical composition, bulk density and open porosi- ty of bauxite are important, but also its microstructure has to be considered, such as phase composition, crystal size and pore size distribution.

Black Box Modeling Method and Its Application in Refractories Techniques

Concept of black box, condition of modeling and control methods were introduced. Taking high purity silica brick as an example, the silica brick featured with high purity, low porosity, low true density and high strength was developed through problem analysis, test design, modeling and optimization. Using information technology to upgrade refractories industry was discussed.

Composite Design of Low Thermal Conductivity Mullite Brick for Application to Cement Kiln

In order to restrain cement kiln shell＇ s thermal loss and potential safety hazards,composite design was employed of working layer,thermal preservation layer and thermal insulation layer.Thermal preservation layer＇ s boundary and strain were analyzed and the overall thermal conductivity was calculated.The result shows that the sinusoidal curve boundary combination is adopted between the working layer and thermal preservation layer,and the slope-shape with angle of 135 degrees between the thermal preservation layer and thermal insulation layer could relieve the strain concentration.Comprehensive thermal conductivity of the composite mullite brick decreases from the working layer 2.74 W·m^（-1）·K^（-1） to1.54 W·m^（-1）·K^（-1）.When applying the composite bricks in cement kilns,the kiln shell temperature is from50 ℃ to 70 ℃ lower than using normal bricks.

Refractories Quality Improvement for Glass Industry Upgrading

1 Glass Industry and Refractories Industry Closely Connect1.1 Glass Development Drives Refractories Progress Refractories are indispensable to glass lnaustry; the rapid development of glass industry drives the growth of refractories industry. China＇ s glass industry developed slowly before the mid 1980s. The kilns and furnaces were backward and small-scale with furnace life of only 2 -3 years; glass was produced with extremely low efficiency and poor quality.