Effects of different crystallization temperatures on temperature difference, crystallization and physical properties of silica manganese slag cast stone

The direct preparation of glass-ceramics from slag is an efficient way to utilize both the "slag" and "heat" of the slag, making it a hot research topic. This paper utilized silico-manganese slag as the main raw material, with the addition of chromite and serpentine as modifiers, to prepare glass-ceramics using the Petrurgic method. The Petrurgic method is a heat treatment process involving controlled crystallization during slag cooling to form glass-ceramics. The prepared glass-ceramic samples had a diameter of 100mm and a height of 20mm. Various tests and analyses such as X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), flexural strength, compressive strength, water absorption, and bulk density were performed on the samples. The influence of different heat treatment regimens on the phase composition and properties of the silico-manganese slag microcrystalline glass was discussed. Additionally, the study investigated the temperature variation inside the glass-ceramic samples The results indicated that by modifying the slag and annealing it at 700°C after cooling to the crystallization temperature, microcrystalline glass meeting the performance requirements of natural granite could be obtained. The temperature range of 900~1050°C was found to be associated with the crystallization of augite phase, while the temperature range of 1000~1050°C was related to the crystallization of akermanite phase. With the improvement of heat treatment system, the amount of akermanite phase precipitation will increase, and the grain will become more coarse. Although at 900°C the grain growth of the microcrystalline glass was not as significant as in the samples annealed at 1000°C and 1050°C, the lack of excessive crystallization led to fewer defects inside the glass-ceramics. After studying the temperature profile data, it was observed that during the heat treatment process at 1000~1050°C, the inconsistent crystallization between the inner and outer parts of the sample resulted in a temperature gradient from the center to the edge. After studying the temperature profile data, it was observed that during the heat treatment process at 1000~1050°C, the inconsistent crystallization between the inner and outer parts of the sample resulted in a temperature gradient from the center to the edge. However, At 900℃ heat treatment conditions, the temperature of Center part and edge part remained consistent during the crystallization stage. For the heat treatment at 800℃, the temperature of the slag quickly decreased below 900~1050℃, making it difficult for crystallization to occur. The overall trend of temperature difference between Center part and side part of the sample was similar for all four heat treatment conditions. After casting the slag into the mold, temperature gradients are formed within the sample, which do not affect the types of crystalline phases that precipitate, but do affect the quantity of crystallization.