Both national standards (YB/T 384-1991) and German standards (DIN 1089-3) divide coke oven siliceous refractory mud into two grades according to chemical composition, but the requirements for the chemical composition of siliceous refractory mud for corresponding grades are obviously different.

Since the silica mortar is usually equipped with natural silica and organic binders containing burning-reducing components, the chemical composition values of the burning base and the drying base displayed by the same material are different, and the drying base is lower than that of the burning base. According to the test results, the silica mortar produced by several silica mortar factories in Liling, Hunan Province, the main producing area of silica mortar in China, is JGN-92. At about 1.5%; JGN-85 brand, the dry base SiO2 content can almost reach more than 90.5%, and the ignition loss is usually less than 2.0%. If converted into a burning basis, it is almost equivalent to more than 94.0% and 92.0% of SiO2 content. That is to say, although the main components of the silica mortar currently produced in my country are lower than those of the German standard, in fact, the main components required by the German standard are basically the same.

The silica mortar currently produced in my country has the biggest difference in chemical composition from the requirements of the German standard, which is the requirement for impurity content. According to the test, the coke oven siliceous refractory mud produced in the Hunan area, the JGN-92 brand burning base impurity content is generally as follows: Al O 2.0%～3.0%; Fe O 1.0～2.0%; CaO 0.5%～1.0%; TiO, MgO, Na2O, K2O trace.

According to the German standard, the main components of the silica mortar produced in my country basically meet the requirements, and the impurity content of "Al2O3 +TiO2" is far better than the index requirements, but the content of "Fe2O3 + CaO + MgO + Na2O + K2O" is seriously exceeding the standard. It is a substandard product. However, whether the requirements of the German standard for the type and content of impurities are reasonable, how much influence the type and content of impurities have on the performance of silica mortar, and whether it must meet the requirements of the German standard to meet the needs of super-large coke ovens, no one has done this. research work. Therefore, this paper conducts an experimental study on it.

In this paper, it is believed that the influence of impurity content on the performance of silica mortar is mainly high-temperature characteristics. is also acceptable. The requirements for the high-temperature performance of silica mortar in Chinese standards are that the load softening temperature T0.6 is greater than 1500 ℃, and the German standard requires that the creep of "silica brick + fireclay" masonry at the service temperature does not exceed ±0.3 of the silica brick. %. Since the load softening index required by the national standard is tested by the heating method, the test result includes the thermal expansion of the testing instrument itself. The softening temperature of the silica mortar itself is actually much lower than the test value, so the required load softening temperature is also higher than the actual value. The operating temperature is much higher. The German standard uses the creep test method to detect the high-temperature performance, which completely simulates the actual use conditions of the silica mortar. It is a very accurate measurement to determine whether the high-temperature resistance of the silica mortar can meet the requirements of use directly from the test results. Therefore, this method is used in this paper to test the silica mortar ingredients with a SiO2 content of more than 94% (burning base) and different impurity contents.

The test results show that the silica mortar whose main component SiO2 content is more than 94%, but the impurity content does not meet the requirements of the German standard, as long as the ratio is reasonable, the softening temperature (heating method) can be higher than the national standard requirements. The creep at 1450°C and load of 0.4MPa) is also required by the German standard, and its high-temperature resistance can fully meet the requirements of super-large coke ovens. That is to say, the type and content of impurities in silica mortar do not necessarily meet German standards. The test data are shown in Table 2.

In addition, in theory, silica mortar is used as a joint material for silica brick masonry. There is no guest chemical reaction in the use of the product, so as to obtain a better use effect. However, the requirements of the German standard for the impurity composition of silica mortar (Al2O3+TiO2) are far looser than those of silica bricks (Al2O3≤1.5/2.0%), and the requirements for other impurities (Fe2O3+ CaO+MgO + Na2O + K2O) are far more Silica bricks (Fe2O3≤1.0%; Ca0≤3.0%, Na2O+ K2O≤0.35%) are harsh. It can be seen that the German standard's requirements for the impurity composition of siliceous refractory mud are unreasonable. Therefore, it is not necessary to adopt the German standard for the composition requirements of siliceous refractory mud for super-large coke ovens in my country.

However, in terms of the chemical composition requirements of silica mortar, it is more scientific for the German Standard to use the sintering base as the test benchmark. This point has been adopted when the new national standard for silica mortar was approved in 2010. The brand of the new standard coke oven silica mortar has been consistent with the German standard, both are burning-based, and the grades are also 94% and 91% SiO2 content. % two kinds, but the type and content of impurities are not required. This is technically reasonable.