The geology of the region was formed before the time of cretaceous and Jurassic in Earl Calloway and Cassian, two original forest area, Indonesia. Due to being rich in various of ore, granite diorite porphyry, Angle of rock, quartzite, coagulation earth rock, silicified wood, aplite and hydrothermal metallogenic essential substances, so the mineral resources are particularly abundant.
Longteng Co.,LTD have a mine with Copper, Ph, Zinc and more in Indonesia. Here, because of relatively backward technology of the mine process in mineral industry, Longteng would like to cooperate with a mining machinery company proficient in advancing ore process technology, and outsource the whole project. After communicating with several powerful mining machinery company Longteng decided to choose Mining Machinery Company with over two decades of experience of mineral process EPC.
Upon signing the contract, Xinhai send some technicians on mission to take sample to do a study and analysis on the mineral composition, and they found that the main elements are pyrite, binding iron sphalerite, galena, pyrite, sphalerite, chalcopyrite and the nonmetal minerals are mainly quartz, feldspar, followed by calcite, dolomite, sericite, chlorite and carbon, etc.
The technicians did a further study and found that in this mine there are chalcopyrite, magnetic iron pyrite, sphalerite, galena, which existed in a situation of symbiotic relationship, and part of them existed in marmatite with a milky state. For that matter, crushing cannot finish the work to separate the mine directly. Part of chalcopyrite included in the gangue particles, so it might loss much along with the tailings discharging, which caused a big effect on the copper recovery rate. Iron sphalerite is the main zinc mineral including fine grain of galena, pyrrhotite, carbon, etc. So it is difficult to achieve monomer dissociation. In addition to the iron content of marmatite is more than 10% on average, which much affects the zinc concentrate grade.
For this kind of complex mine, the target of achieving higher mineral processing index cannot be reached. Even for Xinhai Company it was also a big challenge. Ultimately technicians determined tot adopt the solution of copper lead mix-mining flotation, mixed concentrate separation of copper and lead, and zinc tailings on the basic of low copper content according to many times of mining flotation test. A detailed introduction of mining flotation process designed by Xinhai Company is as following.
1. Copper lead mix-mining flotation
With the condition of mixing slime slurry, the PH reaching around 7.5, having the Ty - 1 and zinc sulfate as inhibitors of sphalerite, iron sphalerite, having ethyl xanthate (70 g/t), J - 21 (35 g/t) as a collector, the zinc, lead and copper were separated efficiently and keeping the foam viscosity moderate to create conditions for the next step of separating copper and lead.
2. Separation of Copper and Lead
With the method of CMC - potassium dichromate to floating copper and having B butter and 2# as collector and frother, and keeping mining flotation foam stability, copper concentrate could be processed efficiently, but the lead concentrate grade was only about 4%, belonging to the coarse lead concentrate. In order to reach a higher index of lead concentrate, gravity separating, shaking table work was be adopted to achieve lead concentrate according to he mineral density differences in lead concentrate.
With the condition of having lime (3500 g/t), copper sulfate (500 g/t), butyl xanthate (60 g/t),2# oil (60 g/t) as reagents and the floating PH between 12-13,zinc roughing processing from the tailings was operated to get zinc concentrate. After the roughing work, two times of concentrating and one time of scavenging was finished to get better lead concentrate.
With the mining flotation process designed by Xinhai, the index was beyond Longteng’s prediction. Finally the result was great（the copper concentrate grade 24.06%, recovery rate 51.70%, and lead concentrate grade of 58.3%, the recovery rate of 89.24%, zinc concentrate grade was 47.08%, the recovery rate of 87.21%).
Besides higher process index, this flotating process also have many characteristics, such as simple process, short process, and stable indicators and so on. It was easy to implement, and met environmental requirements. Xinhai Company not only did an excellent service for Longteng Company, but also won a good reputation for his own in Indonesia through this EPC service project.