This paper presents the ways of comprehensive utilization of the natural magnesium containing resources and the trends of the MgO based refractories used in high temperature industries. In the first part, the uses and...This paper presents the ways of comprehensive utilization of the natural magnesium containing resources and the trends of the MgO based refractories used in high temperature industries. In the first part, the uses and productions of metal Mg, sorel cement, Mg (OH) 2 fire retardant, light magnesium carbonate, light magnesia and magnesium sulphate are described. In the second part, the developments of MgO based refractories used in steelmaking process, nonferrous metallurgy, cement rotary kiln and waste melting furnace are described from some applied theories, including corrosion resistant and slaking resistant MgO CaO materials, chrome free bricks such as MgO CaO ZrO 2 , MgO MgO Al 2 O 3 , MgO MgO·Al 2 O 3 ZrO 2 , MgO MgO·Al 2 O 3 2MgO ·TiO 2 and MgO FeO·Al 2 O 3 , and MgO containing monolithic refractories etc.展开更多
Based on the relevant phase diagrams of ternary system in MgO - CaO - ZrO2 - SiO2 quarternary systems, the phase diagram of Fe - O system and the condensed phase stability area diagram of iron oxides, the corrosion re...Based on the relevant phase diagrams of ternary system in MgO - CaO - ZrO2 - SiO2 quarternary systems, the phase diagram of Fe - O system and the condensed phase stability area diagram of iron oxides, the corrosion resistance of MgO - CaO - ZrO2 refractories to silicate cement, and the forming conditions and prepar- ing measures of hercynite are analyzed.展开更多
Based on the sandwich test, adherence mechanisms of cement clinker on various basic bricks were tackled by microstructural observations with help of cathodolumi-nescence technique. Doloma based bricks offer sufficient...Based on the sandwich test, adherence mechanisms of cement clinker on various basic bricks were tackled by microstructural observations with help of cathodolumi-nescence technique. Doloma based bricks offer sufficient lime to react with clinker, forming C3S rich layer and initializing superior adherence. However, clinker with low silica ratio leads to MgO agglomeration at the interface of doloma bricks, which reduces adherence strength. On magnesia spinel bricks , fine, crystalline spinel easily reacts with lime containing phases from clinker to form low-melting phases and belite zone, which shows high adherence performance. Lack of fine spinel in magnesia spinel bricks results in poor adherence.展开更多
Managers of cement plants are gradually becoming aware of the need for soft sensors in product quality assessment. Cement clinker quality parameters are mostly measured by offline laboratory analysis or by the use of ...Managers of cement plants are gradually becoming aware of the need for soft sensors in product quality assessment. Cement clinker quality parameters are mostly measured by offline laboratory analysis or by the use of online analyzers. The measurement delay and cost, associated with these methods, are a concern in the cement industry. In this study, a regression-based model was developed to predict the clinker quality parameters as a function of the raw meal quality and the kiln operating variables. This model has mean squared error, coefficient of determination, worst case relative error and variance account for (in external data) given as 8.96 × 10<sup>–7</sup>, 0.9999, 2.17% and above 97%, respectively. Thus, it is concluded that the developed model can provide real time estimates of the clinker quality parameters and capture wider ranges of real plant operating conditions from first principle-based cement rotary kiln models. Also, the model developed can be utilized online as soft sensor since they contain only variables that are easily measured online.展开更多
Properties of magnesia-hercynite brick were studied. The coatability, thermal shock resistance, corrosion resistance to cement clinker and thermal conductivity were compared with those of magnesia-chrome brick and mag...Properties of magnesia-hercynite brick were studied. The coatability, thermal shock resistance, corrosion resistance to cement clinker and thermal conductivity were compared with those of magnesia-chrome brick and magnesia-spinel brick used widely in sintering zone of cement rotary kiln. The result shows that magnesia-hercynite brick is better than magnesia-chrome brick in thermal chock resistance and corrosion resistance to cement clinker, is similar to magnesia-chrome brick and is better than magnesia-spinel brick in coatability and thermal conductivity.展开更多
文摘This paper presents the ways of comprehensive utilization of the natural magnesium containing resources and the trends of the MgO based refractories used in high temperature industries. In the first part, the uses and productions of metal Mg, sorel cement, Mg (OH) 2 fire retardant, light magnesium carbonate, light magnesia and magnesium sulphate are described. In the second part, the developments of MgO based refractories used in steelmaking process, nonferrous metallurgy, cement rotary kiln and waste melting furnace are described from some applied theories, including corrosion resistant and slaking resistant MgO CaO materials, chrome free bricks such as MgO CaO ZrO 2 , MgO MgO Al 2 O 3 , MgO MgO·Al 2 O 3 ZrO 2 , MgO MgO·Al 2 O 3 2MgO ·TiO 2 and MgO FeO·Al 2 O 3 , and MgO containing monolithic refractories etc.
文摘Based on the relevant phase diagrams of ternary system in MgO - CaO - ZrO2 - SiO2 quarternary systems, the phase diagram of Fe - O system and the condensed phase stability area diagram of iron oxides, the corrosion resistance of MgO - CaO - ZrO2 refractories to silicate cement, and the forming conditions and prepar- ing measures of hercynite are analyzed.
文摘Based on the sandwich test, adherence mechanisms of cement clinker on various basic bricks were tackled by microstructural observations with help of cathodolumi-nescence technique. Doloma based bricks offer sufficient lime to react with clinker, forming C3S rich layer and initializing superior adherence. However, clinker with low silica ratio leads to MgO agglomeration at the interface of doloma bricks, which reduces adherence strength. On magnesia spinel bricks , fine, crystalline spinel easily reacts with lime containing phases from clinker to form low-melting phases and belite zone, which shows high adherence performance. Lack of fine spinel in magnesia spinel bricks results in poor adherence.
文摘Managers of cement plants are gradually becoming aware of the need for soft sensors in product quality assessment. Cement clinker quality parameters are mostly measured by offline laboratory analysis or by the use of online analyzers. The measurement delay and cost, associated with these methods, are a concern in the cement industry. In this study, a regression-based model was developed to predict the clinker quality parameters as a function of the raw meal quality and the kiln operating variables. This model has mean squared error, coefficient of determination, worst case relative error and variance account for (in external data) given as 8.96 × 10<sup>–7</sup>, 0.9999, 2.17% and above 97%, respectively. Thus, it is concluded that the developed model can provide real time estimates of the clinker quality parameters and capture wider ranges of real plant operating conditions from first principle-based cement rotary kiln models. Also, the model developed can be utilized online as soft sensor since they contain only variables that are easily measured online.
文摘Properties of magnesia-hercynite brick were studied. The coatability, thermal shock resistance, corrosion resistance to cement clinker and thermal conductivity were compared with those of magnesia-chrome brick and magnesia-spinel brick used widely in sintering zone of cement rotary kiln. The result shows that magnesia-hercynite brick is better than magnesia-chrome brick in thermal chock resistance and corrosion resistance to cement clinker, is similar to magnesia-chrome brick and is better than magnesia-spinel brick in coatability and thermal conductivity.
