Kaolin will produce a large number of tailings after mineral processing recovery. Due to the less recycling of Kaolin Tailings, with the continuous accumulation of tailings, it will occupy a lot of lands, pollute water quality, cause vegetation damage and soil erosion, and even cause debris flow, which seriously affects the ecological environment. Therefore, the comprehensive utilization of Kaolin Tailings and their recycling can effectively prevent the waste of resources and damage to the environment.
At present, the comprehensive utilization of Kaolin Tailings in China is mainly divided into the recycling of valuable components in Kaolin Tailings and the processing and reuse of Kaolin Tailings.
1. Recovery and utilization of valuable components in Kaolin Tailings
Kaolin Tailings often contain a large number of silicate minerals such as quartz, muscovite, and feldspar. These minerals can be recovered through appropriate recovery processes, such as gravity separation, flotation, desliming, etc. mica concentrate, feldspar concentrate, and quartz concentrate can be obtained, and even tailings free separation can be achieved.
A kaolin tailing in Jiangxi Province is mainly composed of quartz, muscovite, feldspar, and a small amount of kaolinite, in which the harmful impurities are mainly iron and mainly occur in limonite. Chengyu et al. Adopted the classification flotation process, first flotation muscovite, then flotation separation of feldspar and quartz. The mica, feldspar, quartz, and other concentrates meet the requirements of technical indicators and realize tailings free beneficiation. Through the recovery and utilization of tailings, the annual profit can be increased by 2.3 million yuan.
In the process of comprehensive recovery and utilization of pyrite-rich kaolin, due to the easy marginalization of kaolin, fine and fine kaolin has a great influence on the flotation separation of pyrite. Cao Xuepeng carried out comprehensive recovery and utilization of pyrite-rich kaolin in a certain area. The content of kaolinite and pyrite in raw ore was 79.82% and 18.14% respectively. The pyrite concentrate with a sulfur grade of 48.77% and sulfur recovery rate of 87.30% was obtained through primary roughing, secondary cleaning, and secondary scavenging with acidified sodium silicate as regulator and butyl xanthate as the collector. The amount of sulfur and iron in kaolin decreased to a certain extent after purification.
2. Processing and reuse of Kaolin Tailings
The main components of Kaolin Tailings are SiO2 and Al2O3, and a small amount of K2O, Na2O, Cao, MgO, and so on. The characteristics of Kaolin Tailings can be used as raw materials in some fields.
Liu Zhixing used Kaolin Tailings instead of quartz and some feldspar to produce glass. The dosage of Kaolin Tailings in the formula can reach more than 60%. At the same time, sericite in Kaolin Tailings can reduce the consumption of soda ash and reduce the production cost. Kaolin tailing also contains more K2O and Na2O, which has little effect on the viscosity of liquid glass. On the contrary, it is beneficial to improve the hardness, mechanical strength, thermal stability, and chemical stability of glass products.
Wen Xilian compared and analyzed the physical properties of Maoming Kaolin Tailings and natural sand, and found that the particles of Maoming Kaolin Tailings are fine, the firmness is slightly poor, the angularity is slightly large, the surface is coarser than the river sand, and other properties are close to river sand. The properties of C40 and C65 concrete prepared by combining Kaolin Tailings with river sand are obviously improved.
Under the background of China's sustained high-speed economic growth, continuous consumption of mineral resources, and increasingly serious environmental problems, a large number of Kaolin Tailings need to be treated urgently. Therefore, it is necessary to improve the research on comprehensive utilization technology of tailings and turn waste into treasure. Tailings will also become a widely used secondary resource, which is also the construction of resource-saving Environmental friendly society and an important way to achieve sustainable development.