About the author: Luo Handong, Ph.D. candidate, engaged in ecological restoration and management of quarries.
China is one of the countries with the most abundant rare earth resources in the world and is known as the “Kingdom of Rare Earths.” Ionic rare earths in southern China are the main source of this important strategic resource in the world and play an important role in the field of high-tech product manufacturing. China’s dependence on high consumption of rare earth resources, China’s uncontrolled exploitation of rare earth resources, disordered management, and backward technology have led to the decline of resource reserves and serious damage to the ecological environment of rare earth mining areas. The environmental problems arising from its development have had a significant impact on the production and lives of the people, so the ecological restoration and management of rare earth mines is very important. This book introduces the basic theory of ecological restoration and management of rare earth mines in the south, divides the types of ecological damage and ecological restoration measures of rare earth mines in the south, and expounds the importance of rare earths, the sources of pollution caused by rare earth mining, and the harm to human health caused by rare earth mines. The main ecological and environmental problems in the mining process, the geological environmental problems and hazards in the mining area, and the measures for ecological restoration and management of rare earth mines, etc., have drawn up the principles and goals of ecological restoration and have affected a large number of rare earths in various aspects. Application status and examples of ecological restoration and management, as well as the estimated benefit after treatment, further explain the necessity of ecological restoration and management of rare earth mines.
This book can provide a theoretical basis for the ecological restoration design of rare earth mines; provide a theoretical basis for the construction, supervision, and acceptance of ecological restoration projects; as well as rare earth m
The term “rare earth” is a name left over from history. Rare earth elements have been discovered one after another since the end of the 18th century. At that time, people often referred to the solid oxides insoluble in water as “soil.” Rare earths are generally separated in the state of oxides and are very rare, so they are named rare earths. Pu, Wrong, Qin, Ju, Jun, and Pin are usually called light rare earths or Pei group rare earths; Zhao, Shi, dysprosium, iron, bait, Yu, ho, and Lu are called heavy rare earths or group rare earths. Some are based on the similarity and difference between the physical and chemical properties of rare earth elements, In addition to this (some classify Chong as scattered elements), they are divided into three groups. That is, the light rare earth group is Lan, Pu, Wrong, Qin, and Ju; The rare earth group includes Jun, Pin, Vanadium, Spade, and Dysprosium; The heavy rare earth groups are Qin, Yu, Hua, Hao, Lu, and Xuan. At present, the most commonly used raw materials for the production of rare earth metals are their chlorides and fluorides.
China is extremely rich in rare earth resources and is the world’s largest producer and country of rare earth resources, of which about 98% comes from carbonatite-type rare earth deposits. What is carbonatite? This is a magmatic rock mainly composed of carbonate minerals, Compared with granite and other magmatic rocks, it is very rare and has a very limited distribution in the world, but it provides more than 90% of the world’s rare earth resources.
Carbonatite is a typical mantle-derived magmatic rock, So is the mantle rich in rare earths? Usually not, Subduction of subducting fluids or melts and recycling of rare earth-rich oceanic sediments are required to form rare earth-rich mantle source regions, Therefore, carbonatite-type rare earth deposits are distributed along the edges of ancient cratons, such as Bayan Obo, Miao Yaa, Xi Shan, and yak ping.
Partial melting of the rare earth-rich lithospheric mantle to form the initial magma of carbonatite-carbonated silicate magma，The magma experienced a complex evolutionary process during the intrusion，including immiscibility, crystalline differentiation, In particular, the immiscibility between mafic-ultramafic magmas and carbonate magmas and the crystallization and separation of basic minerals may be important reasons for the enrichment of rare earths in carbonate magmas，The crystallization and differentiation of carbonate minerals further enriches rare earths in the late fluid-rich carbonate magma，This can explain why carbonatite-type rare earth mineralization all occurred in the late carbonatite evolution. So are carbonatite-type rare earth deposits magmatic deposits? Mostly not, The rare earth mineralization of carbonatite-type rare earth deposits mainly occurs in the carbonatite fluid stage, The inclusions in rare earth minerals and contemporaneous barites are mainly fluid inclusions. So what are the properties of carbonate rock fluids? Why is it so rich in rare earths? The researchers found by studying the melt and melt fluid inclusions in the fluorite of the Yak ping rare earth deposit, Carbonatite fluids are obviously different from the ore-forming fluid systems of other endogenous metal deposits, It is very rich in sulfate ions and in a variety of metal elements, Including K, Na, Ca, Sr, Ba, REE, Pb, Zn, etc.，is a unique sulfate-rich fluid system，This fluid has a fairly high rare earth solubility.