Southern rare earth mining multiple hazards exist

Between the southern provinces of Jiangxi, Fujian , Hunan, Guangdong , Guangxi, Yunnan and other mountains, rich in ionic heavy rare earth resources, this is a special rare earth deposits only a few countries , such as our own, which has proven reserves , representing the world's proven ionic heavy rare earth resources in more than 90% .

In recent years , the South -ionic heavy rare earth mine commonly used in-situ leaching process development of rare earth . In this regard, the rare earth industry stakeholders in an interview with our correspondents pointed out that although the recovery compared with the past ionic heavy rare earth ore leaching pool , in-situ leaching of heavy rare earth ionic technology in mining and other environmental indicators have been considerable progress , but the use of this technology to develop ionic heavy rare earth resources , easy to destroy mine geological structure , triggering landslides . Meanwhile, since the mine design defects , some chemicals used in the leaching process also rare risk of leakage .

They called on relevant departments to be able to give attention to the potential security risks and take preventive measures targeted .

Rare is a valuable strategic resource, because of its unique magnetic, optical, electrical and other physical and chemical properties , are widely used in high-tech fields of aerospace , electronic information, the nuclear industry , new energy, advanced manufacturing , development of emerging industries of strategic important strategic significance.

Engaged in research work of production safety in Ganzhou Rare Earth Mining Co.黄紫彬, who said ionic heavy rare earth ore was discovered in the South in the 1970s , it was in the chemical weathering and other natural effects , rich in rare earth elements from the parent rock rare earth ions formed first and then the clay was adsorbed into an aqueous solution formed . And enrichment of rare earth mine in the north of a small piece of mine in a different , lower ore grade heavy rare earth south , but particularly wide distribution area. For example , in the global distribution of heavy rare earth mines in Ganzhou richest Long County and other places, the mountains and plains are dotted with almost ionic heavy rare earth resources.

" Rare is the general term lanthanum, cerium , praseodymium , neodymium, terbium , dysprosium and other 17 kinds of elements ," Zhang Anwen , deputy secretary general of China Society of Rare Earths , said , " lanthanum , cerium and other five kinds of rare earth elements are called light rare earths ; scandium is generally not symbiosis with other rare earth elements , known as dispersion element , promethium are radioactive elements in the rare earth minerals so far have not found ; other 11 kinds of rare earth elements terbium , dysprosium , etc. are called heavy rare earth elements. "

Nature reserves of heavy rare earth deposit in the form of industrial rarely . Zhang Anwen told reporters , heavy rare earth known as the "King of rare earth ," is the scarcity of rare species , China's proven ore reserves of heavy rare earth ion type , only a few hundred tons, mainly for defense and other cutting-edge combined science and technology , so a greater strategic importance than light rare earths , and the price is much higher than the light rare earths .

For example , in July 2012 the best rare earth prices , the most popular varieties in the light rare earth praseodymium, neodymium metal per ton price of 100 yuan up and down , but terbium , dysprosium heavy rare earth prices 20 million yuan per ton , respectively , 1300 million or so , you can see from the price , LREE far on strategic value.

Zhang Anwen said heavy rare earth mine south of shallow , easy to exploit . Over the past few decades , people continue to improve mining methods to explore in situ leaching out of the process, that is , without stripping and mining of ore , the first hit on a lot of holes in the mountain containing rare earth ore is then injected and recovered for leaching chemical rare earth elements , rare earth elements and further separated by chemical methods. Compared with the initial pool leaching process , rare earth recovery of this process is high, but when you do not have to peel ore mining and destruction of vegetation , labor intensity is also small, simple method has been widely used.

However, in situ leaching , liquid injection drilling drawback of this process is obvious. Zhang Anwen said that , in general, the heavy rare earth mine in the southern part of the hilly terrain topography , altitude generally between 300 meters to 400 meters, the relative height between the mountains is generally between 50 meters to 100 meters . Rock weathered granite mine to the main structure of the mountain rock itself is not strong enough .

In addition , with the in-situ leaching process rare earth mining , need to play a certain amount of liquid injection wells rich in rare earth mine in the mountains . Under normal circumstances , you need to be disposed on the mountain with hundreds of rare earth ore even thousands liquid injection wells , holes on the mountain , combined with the vibration generated in the drilling process , and will destroy the mountain was originally a stable internal structure of the state , resulting in the mountain loose .

Especially so after liquid injection wells , the worker will inject a large amount of leaching solution into the mountain , the mountain due to absorption of a large number of pharmaceutical and become soft, sticky soil mountain also decreased with increasing moisture content , maintain the balance of power structure of the mountain had also been damaged, prone to landslides accident. Adequate rainfall especially in the southern regions , repeatedly washed in the rain , had " drink enough " of the leach solution mining mountain more prone to collapse and landslides phenomenon . Zhang Anwen said that the actual situation also showed that the mountain of rare earth mine collapses, landslides and more hair. This article Source : Lookout Observation Network

Huangzi Bin has done this research expertise . He said that in the actual production , some producers to produce benefits as soon as possible , often used to increase the amount of fluid injected into the leach ore ways to accelerate the speed , a substantial increase in the amount of fluid injection , the change will add to the already saturated loose burden on the mountain , increasing the probability of landslides , some of the rare earth mine in Jiangxi mountain landslide is so produced , which seriously threatened the safety of life and property construction and mining mining area residents.

In general, the injection of ore leaching solution , after some time, will be recycled to the loop processing of the pool, and then precipitation of ammonium bicarbonate or oxalic acid solution obtained by leaching agent treatment , thereby separating the rare earths.

According Huangzi Bin introduction , stope design , in order to make better use of its own gravity leach solution , let gravity in order to save energy and other costs, types of mines hydrometallurgical processing plant mines along the hillside pool often , by the ladder layout, pond liquor pools earlier treatment processes are generally arranged in a workshop on the higher terrain of the platform , the rest of the processing tank process , press down sequentially arranged in the order .

Rare earth mine in South Jiangxi example, mine hydrometallurgical plant generally include liquor transit pool , cleaning tanks, sedimentation tanks , melting tanks and miscellaneous other types of liquid pool with Process pool. Pond based on the actual number of mine production scale , the number ranging from a few to dozens , usually in a single volume 200 cubic meters to 300 cubic meters. These multi- process cement and brick and concrete pools build from , with some compression capability . However , in the actual production process, are open-air hydrometallurgical plant operations, treatment ponds are directly exposed to the sun , Over time, wind and sun, the wall is easy to crack.

Huangzi Bin example , if a treatment tank capacity of 250 m3 , in the case of the pool fills , the wall pressure is great. Once the pond wall collapse collapse phenomenon occurred , two or three tons of liquid mixed with debris flows down from the high slope, staff will bottom , facilities pose a great threat . Thus , process tank collapse in ionic rare earth ore production process is also a source of great danger .

Hazardous chemical reagents owe specification , is another big issue during development of rare earth mine south facing . Huangzi Bin analysts say , the use of in-situ leaching of mining rare earth mine in the removal of impurities link, mining companies tend to use strong acid and other chemicals to recover the residual waste earth, scum first method is generally used strong acid to dissolve and then re- send Metallurgical plant for separation into the water , the use of strong acid is usually concentrated sulfuric acid.

Concentrated sulfuric acid has a strong oxidation and corrosion , but also has dehydration , hard -volatile characteristics, likely to cause harm to the human body, is one of the country 's strict control of hazardous chemicals .黄紫彬said some mining companies to store using metal cans of concentrated sulfuric acid , which has a bottom gate metal cans often , when used to unscrew the valve , concentrated sulfuric acid will flow . Because sulfuric acid tank is generally placed outdoors, wind and sun, easy to rust, above often no safety valve control device , these factors may result in concentrated sulfuric acid leak accident , there are security risks .

In addition , the use of chemicals in accordance with specifications , should dilute the concentrated sulfuric acid is added to water, stirring slowly , otherwise prone to the phenomenon of boiling solution . However, affected by the mine management and the quality of workers , some workers on the nature of the lack of adequate knowledge of concentrated sulfuric acid , concentrated sulfuric acid in the dilution , the presence of concentrated sulfuric acid in the water directly into the mixing phenomenon , likely to cause injury.

For Southern rare earth mining security risks , interview with our correspondents and business experts have suggested :

First, the national authorities should increase South -ionic heavy rare earth mineral exploration investment in the distribution of resources to find out the " real situation" and distribution , thus formulating a unified development plan ; article Source : Lookout Observation Network

Secondly, lack of current mining technology exists , the proposed national scientific and technical personnel and other relevant ministries and departments of geological research organizations , combined with rare earth mine geology south , to further improve and perfect the ionic heavy rare earth mining technology ;

Third, establish and improve mine planning , process, production facilities protection and other safety norms and standards as soon as possible , safety supervision departments to implement the responsibility , through the organization of security checks , etc., and urge enterprises to enhance safety awareness and improve the safety level of production. At the same time , increase the illegal exploitation of rare earth mine south behavior crackdown ;

Fourth, the use of acid and alkali rare earth mines and other dangerous goods , the relevant departments to strengthen management, establish qualification examination and approval system , and urge enterprises to establish and implement related operations , management practices ; operating personnel related positions , to be dedicated job skills , safety awareness training, job evaluation .


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