There are three kinds of Bayer-sintering combined methods that are practically applied in the production of alumina, namely, the in-line method, the parallel method, and the hybrid method. The classification is mainly the source of raw materials processed by the sintering method. The so-called Bayer-sintering in-line method means that the sintering method is partially used to treat the Bayer red mud. The main advantages of this method are that the total recovery of alumina is high, the alkali consumption is low, and the sintering method has a small yield. However, in the sintering method part, the alumina content in the red mud charge is low, the clinker conversion ratio is high, and sintering is difficult. In the traditional Bayer-sintering parallel method, Bayer process and sintering process are two parallel production systems. The Bayer process treats high-grade ore, whereas the sintering process does not treat Bayer red mud but only ore. The advantage of this method is that it can not only handle high-quality bauxite, but also can handle ore with lower aluminum and silicon, and the use of resources is more reasonable. However, because the sintering method is only partly to make up alkali, there is no output of aluminum hydroxide, and the output is affected. limit. The Bayer-Sinter hybrid method used in China is essentially a simple combination of the sintering method and the Bayer-sinter series method. It also has the advantages of the serial method and the sintering method. It can, to a certain extent, exert the production capacity of the sintering method, but the process is more efficient. Complexity, the balance between the two major systems in production practice is more difficult, and the two systems restrict each other and cannot do their best. In particular, in the sintering method, due to the Bayer process's red mud and its own output of silicon slag, the clinker grade is greatly limited, so that the sintering process part yields about 30% less than the pure sintering method, which greatly wastes precious Equipment resources. In view of the problems existing in our country's mixed-law companies, many people in the industry have proposed solutions such as the hybrid technology innovation, the new joint law, and the modern parallel approach. The essence is that the Bayer method and the sintering method in the joint method are relatively independent. The sintering system processes only the ore and produces aluminum hydroxide instead of the Bayer red mud to reduce the mutual interference between the two systems. In order to distinguish it from the traditional parallel method, we propose to call it the modern parallel method. The great advantage of modern parallel methods is their low-cost production expansion. It has been estimated that, compared with the hybrid approach, the modern parallel method allows the Bayer process system to increase production by 10-20% and the sintering process system to increase production by 60%. Due to the substantial increase in production on the basis of the original equipment, it will inevitably lead to a decline in the energy, labor, equipment maintenance and other related costs of the unit product.