Tang Dan Refractory Oxidized Copper And Efficient Use Of New Technology And Industrialization

Copper is one of the most important non-ferrous metals to China's national economy, is widely used in military industry, electricity, telecommunications, transportation, light industry, construction, machinery and other industries. At present, China has a huge consumer demand of copper with the rapid development of industrialization and information. Since 2002, China's copper consumption has exceeded that of the United States, reaching 2600000 tons in 2003,3290000 tons in 2004,4750000 tons in 2005 and nearly 5000000 tons in 2006. However, the self-sufficiency rate of China is only 24%, the weight of copper metal in concentrate is only 650000 tons every year, so China is shorted in copper resources, need to import large quantities of copper concentrate and copper scrap each year. With the mining and utilizing of copper-bearing sulfide minerals, in some foreign copper mining, the grade of coper was fell to 0.4 percent. In China's proven copper resources, there exists a large number of low-grade refractory copper oxide ores, which are not made good use of due to lack of novel high-efficient utilization technologies. A large anmmout of low-grade refractory copper oxide deposits are mainly distributed in such provinces as Yunnan, Hubei, Guangdong, Xinjiang, Inner Mongolia, Sichuan and Heilongjiang etc.. Tangdan copper oxide deoposit in Yunnan province is the largest independent one in the proven reserves of copper oxide so far in China, it maintainins a reserve of about 1000000 tons of copper metal, with an average grade of 0.88%.The research of high efficient joint process of beneficiation and hydrometallurgy was conducted using refractory copper oxide ores in this Ph.D dissertation in order to make good use of them, therefore, it is of great significance. From 1950s, the scientific research on Tangdan refractory copper oxide ores has been carried out continuously, the research work mainly concern flotation, ammonia leaching and various forms of joint process, the results, however, are not satisfied due to the special characteristics of the ore, for instance, the flotation performance are always not good because of the low grade and high oxide ratio, the acid leaching methods are not adopted because of high content of acid-consuming gangues, thus, ammonia leaching is seem to be the best choice, it, nevertheless, can not obtaine good performance for high tempreture and high pressure of the operations. In 1990's, a new flowsheet of normal tempreture and pressure ammonia leaching-extraction-electrowinning, authough makes an important progress, it still has a few disadvantages such as high energy consumption and difficult to continuous operation, which led to the failure of industrialized application.On the basis of full consideration of the exsisting processes, previous studies and the special nature of the oxidized copper ores, another innovative joint process of normal tempreture and pressure ammonia leaching extraction-electrowinning-slag flotation is put forward, which agrees with its special properties and solves the high efficient utilization difficult comprehensively.This Ph.D dissertation is under several state or provincial scientific research projects, such as the tenth-five key project, doctoral fudemental research fund, Yunnan provincial cooperation project and so on. At the same time, Kunming Ruiyuanju Hydrometallurgy Co., Ltd. gives me a lot of help in the study.The process mineralogy, leaching, extraction, solid-liquid separation, electrowinning and slag flotation processes are investigated deeply. Diffirent scale experiments including laboratory, pilot scale with 50 t/d, industrial scale with 300t/d and commercial scale with 1500t/d were also systemically conducted, and good results were obtained through entire process optimization as follows:(1) Process mineralogy study shows that:Tangdan refractory copper oxide ores are with very complex structure and texture, containing various types of copper minerals, very fine disseminated, low-grade, and high mud cotent, which bring lots of difficulty in treating the ore, therefore, the process mineralogy study should be taken into full consideration in the design of process methods.(2) Innovative joint process, normal tempreture and pressure ammonia leaching-extraction-electrowinning-slag flotation(NTP-ALEE-SF), agrees well with the special nature of the copper ores, which not only highly recovered copper oxide minerals by hydrometallurgy process, but also highly recovered copper sulphide and precious metal minerals by flotation.(3) The product program of NTP-ALEE-SF process is very flexible, it can produce not only flotation concentrate but also Cathode Copper, or individual or both according to the type of copper ores.(4) The NTP-ALEE-SF process has more advantages over conventional ones, such as process simple, technology reliable, energy saving, easy to put into production and good to entironment protection, etc..(5) Replacing the extractant LIX54-100 with LIX84-I successfully, which forms the key technologies for copper extraction in the ammonia solution. (6) It should be paid more attention to CO2 concentration when using extractant LIX84-I to extracte copper in NH3-CO2 solution system.(7) The production performances using NTP-ALEE-SF process with 1500 t/d commercial scale are as following:the grade of run-of-mine is 1%, the oxidation ratio is between 55%and 65%, the total copper recovery of concentrate reached 76-77%with a grade of 17-18%, annual profits and taxes more than 0.124 billion Chinese Yuan.(8) Industrial production shows that NTP-ALEE-SF process has good stability and reliability, it can achieve higher recovery of 10-15 percent points than conventional flotation technology.The research of this dissertation has been authorized by a national invention patent, which indicates it is highlight innovative. The main innovation points are as follows:(1) Pointing out for the first time that it should be taken into full consideration in the design and choice of process methods according to the study of process mineralogy.(2) Inventing an innovative technology of normal tempreture and pressure ammonia leaching-extraction-electrowinning-slag flotation (NTP-ALEE-SF), it agrees well with the special nature of the copper ores, Realizing its industrialization.(3) Realizing high efficient leaching of low-grade copper oxide ores by adopting XLD agitating cell for the first time.(4) Replacing the extractant LIX54-100 with LIX84-I successfully for the first time, which forms the key technologies for copper extraction in the ammonia solution.(5) Discovering the importance of CO2 concentration in ammonia extracting solution, and pointing out that existing a critical concentration of CO2.(6) Adopting joint process to realize good performance of solid-liquid separation by hydrocyclone, thicker and belt-filter for the first time.