In recent years, magnesium materials have been widely used，especially，high-purity magnesium materials，which has the advantage of good fire resistance. Research has found that calcium and iron impurities in magnesium materials can reduce their stability and resistance to slag erosion，thereby restricting the development of magnesium materials. The study summarizes the methods for reducing the content of calcium and iron impurities in magnesium materials to improve the purity of magnesium materials. And key research directions for improving the purity of magnesium refractory materials in the future are explored.

In order to recycle industrial waste fly ash and reduce the production cost of cement based foam insulation board，with ordinary PO 42.5 Portland cement as the main gel material， add 8% sulfur aluminate cement as procoagulant，plus 7% hydrogen peroxide as foaming agent， water ash ratio of 0.5，with fly cement instead of Portland cement（replacement of 0，10%， 20%，30%，30%，40%）prepared cement based foam insulation board. The influence of fly ash incorporation on the physical，mechanical and thermal properties of foam insulation plate is studied. The results show that when the fly ash incorporation is 20%，the foam insulation board is the best comprehensive performance，and can also improve the durability of the material.

In order to develop high alumina unfired brick refractory without carbon for ladle，the effects of binder containing carbon（active magnesium oxide and lignin）and binder without carbon （active magnesium oxide and ρ-Al2O3）were compared in this paper. The main body of high alumina refractory was formed by using different mesh numbers tabular corundum as aggregate， fused magnesia powder，200 mesh tabular corundum and alumina powder as matrix, and then added carbon-containing binder or carbon-free binder. The sample is pressed under a certain pressure and then sintered at different temperatures and times，the effects of different binders on the cold compressive strength，bulk density, porosity and permanent change in dimension on heating of high alumina samples at room temperature were investigated. The results showed that magnesiaalumina spinel was formed by activated magnesia and ρ-Al 2O3 at high temperature，and the higher the content of activated magnesia，the better the high temperature physical properties of the samples；The lignin-containing binder increased the compressive strength of the samples at room temperature，but its high temperature performance was poor.

The chromium oxide sintering process is applied to produce the SiC-mullite-zirconia multiphase material featuring excellent performance，with nano-η-Al 2O3 powder taken as the aluminum source and micro-silica as the silicon source to synthesize the associative phase of mullite. With the experiment，the authors probe into the influence of firing temperature exerted on the physical property，phase composition and micro-structure of a multiphase material， and conduct comprehensive thermal analysis of the raw materials. The results show that the SiO2 generated by SiC oxidation is highly active so that it starts to react with the η-Al2O3 in the transient phase under 996.5 ℃，forming solid mullite；the samples boast the best overall performance under 1 600 ℃，with their bulk density reaching 2.82 g/cm3 ，apparent porosity 3.2%, flexural strength 143.2 MPa at room temperature, while oxidation mass gain 0.65% only；the calcined ZrO2 losses its stability，transforms from c-ZrO2 to m-ZrO2，and evenly distributed in the samples；the mullite crystallizes well and bonds tightly with SiC. Key words：Nano-η-Al 2O3；Chromium oxi

Based on the study of the oxidation resistance of Al2O3-SiC-C iron trough castables, the effects of B4C and Si on the microstructure and properties of the castables were systematically studied. The results show that with the increase of B4C content，the oxidation resistance and compactness of castables were improved，and mechanical properties，slag corrosion and penetration resistance were significantly elevated. However，the excessive addition of B4C can increase the formation of low viscosity liquid phase containing boron and reduce the slag corrosion resistance of castables. The addition of Si and the compounding of silicon powders with different particle sizes are conducive to the improvement of compactness and oxidation resistance of castables. Controlling the amount of small particle size simple silicon and reducing the formation of low melting point composite silicate liquid phase is conducive to maintaining the excellent oxidation resistance，mechanical properties and slag corrosion resistance of castables.

Magnesium and calcium brick has good performance of coat adhesion performance when used on the cement kiln combustion zone，but when the kiln is stopped for maintenance or the temperature rises and falls suddenly，cracks and spalling are easy to occur between the MgO-CaO brick and the kiln crust，affecting its service life. MgO-CaO-ZrO2 bricks are prepared by taking MgO-CaO clinker and high purity magnesia as the main raw materials，adding calcium stabilized zirconia，pressing magnesium calcium zirconium bricks by hydraulic press under the pressure of 2 500 t through crushing，screening，batching, mixing and other processes，and firing them in tunnel kiln at 1 580 ℃ . Because calcium-stabilized zirconia is added to the ingredients，the normal temperature performance，hydration resistance and thermal shock stability of MgO-CaOZrO2 bricks are improved，and the stability of coat adhesion performance of MgO-CaO-ZrO2 bricks is also improved. The test shows that when the addition of calcium stabilized zirconia is 3%，its performance is the best.

For the magnesia based castable made up with sintered magnesia，fused magnesia，and silica powder，it was found that the addition of silicon carbide powder can create fibrous needle MgO whiskers on the surface and interface of the castable. The impact of the dosage of silicon carbide fine powder and heat treatment temperature on magnesium oxide whiskers are compared and analyzed. When the temperature reached above 1 450 ℃ in the low oxygen partial pressure region， the magnesium thermal reduction reaction will cause the migration of magnesium vapor to the material surface and interface，and MgO whiskers grow after oxidation. The surface of magnesium siliceous samples with addition of 3% to 7% of 97% silicon carbide fine powder is prone to agglomeration of magnesium oxide whiskers after 3 hours of heat treatment at 1 500 ℃ . Moreover， as the dosage of silicon carbide increases，the generation and growth of whiskers are improved.

A large number of nitrogen oxides (NOx) are produced in the process of hightemperature firing refractory materials in tunnel kiln. In order to meet the emission requirements of flue gas pollutants，flue gas treatment is necessary. Low temperature SCR denitrification (150 ～ 250 ℃ ) technology can better meet the requirements of flue gas pollution treatment of tunnel kiln used for firing refractory materials. Compared with traditional SCR denitrification，it reduces the investment of environmental protection equipment and experience cost.

In order to further improve the performance of Al2O3-ZrO2-C materials，the effect of five different alumina micro-powders on the performance of Al2O3-ZrO2-C slide gate plates are studied with tabular corundum and zirconia-mullite as the main raw materials and phenolic resin as the binder. The results show that：1）With the particle size of alumina micro-powder decreasing gradually, the apparent porosity of the sample increases，the bulk density decreases，and the mechanical properties of the sample at room temperature decrease；2）CL-370 effectively fills the pores due to its bimodal particle size distribution, resulting in a higher bulk density after burning and flexural strength at room temperature of sample A4 than those of sample A3；3）As the particle size of alumina micro-powder gradually reduces，the high temperature flexural strength of the sample increases while the thermal shock resistance decreases.

During fusion sample preparation of high-aluminum and SiC-containing refractories for X-ray fluorescence spectroscopy，problems such as bubbles and corrosion to platinum crucibles are hard to eliminate. In the paper，analysis and experiments are conducted to deal with these problems. The experiments show that the selection of flux and the dosing method are the keys to solving the above problems，and have revealed the best solution. With this solution，the accuracy and stability experiments show a maximum absolute error of 0.04，and a maximum standard deviation of 0.068 7. In addition，the data are proven reliable and accurate by comparing with the traditional chemical method.

The silica gunning material is made by silica material with high content of SiO2 and additives such as silica powder and clay. It has the following advantages，such as good fluidity， low spring-back rate，high strength and good high temperature performance. The utility model is used for hot-state wet gunning of the damaged wall of the pot calciner，which has good effect and prolongs the service life of the pot calciner.

This paper introduces the upgrading and transformation of two 250 m3 coke cocombustion lime kilns with beam kiln technology，the coke co-combustion lime kiln was transformed into a gas burning beam kiln with advanced technology. As a result, the quality standard of environmental protection and ultra-low emissions was achieved.

This paper introduces the energy-saving and environmental protection design and application effect of TGS lime kiln production line，the hardware configuration and software design of intelligent production of sintered ash，and the debugging and maintenance of the system．TGS lime kiln has achieved remarkable results in reducing the ash consumption per ton steel and energy saving and emission reduction through technological innovation．

In view of the fact that the sealing ring of the discharge plate at the bottom of Maerz kiln is easy to be damaged in daily production，this paper analyzes the reasons from the surface control of the finished material of the small material bin at the bottom of the kiln，the action control of the hydraulic cylinder of the discharge plate and the quality control of the finished product calcination，etc.，by improving the material level detector of the small material bin at the bottom of the kiln，adjusting the operating speed of the hydraulic cylinder of the discharge plate，optimizing the process control of the kiln，stabilizing the quality of the finished product and prolonging the service life of the sealing ring.