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Nickel rich resources of the earth, the world has identified nickel metal reserves of about 62 million t [1]. China is one of the countries with rich nickel resources in the world, accounting for about 9% of the total reserves, ranking fourth in the world [2 , 3] . The average content of nickel in the earth's crust is 0.01%, but there are not many mineral deposits. At present, there are mainly three types of nickel sulfide deposits, laterite nickel deposits and weathering shell nickel silicate deposits. Among the existing reserves, laterite ore Nickel silicate minerals account for 70% and sulphide ore accounts for 30%, but currently about 60% of nickel products are derived from sulphide ore [4] . However, there are fewer and fewer sulphide resources available for exploitation in the world. With the rapid development of the world economy, nickel demand has increased and prices have risen. It has become an urgent task to develop and utilize laterite nickel ore and nickel silicate. The wet treatment process is currently the main process for processing laterite nickel ore and nickel silicate ore, mainly ammonia leaching method [5] , high pressure acid leaching method [6] , atmospheric pressure acid leaching method [7] , microbial leaching [8] And other processes.
A nickel-nickel ore in southern China contains 0.70% nickel. The independent nickel minerals include red arsenic nickel ore and orthorhombic arsenic ore. Other nickel minerals are distributed in other nickel-bearing ores in a dispersed state, which has certain development and utilization value. In this study, the research on the nickel-nickel ore by atmospheric pressure acid leaching and nickel extraction laid the foundation for the development and utilization of the mine.
First, the nature of the ore
The ore mineral composition of this study is complex, with many kinds of minerals, and many minerals contain little nickel. Wherein the metal minerals niccolite, orthorhombic arsenic nickel ore, nickel ore magnet, nickel-chromium-containing ore containing pentlandite, a nickel-containing serpentine, arsenopyrite, copper ore, sphalerite, Limonite, etc. Gangue minerals are tremolite, actinolite, olivine, pyroxene, antigorite, sericite, calcite, talc, mica, apatite, graphite, zircon, quartz, chlorite, saponite .
The inclusion characteristics of nickel-bearing minerals in ore are also complicated, and a considerable amount of nickel is dispersed in serpentine, cobalt- containing nickel magnetite, and nickel-containing chromite. The results of multi-element analysis are shown in Table 1.
Table 1 Multi-element analysis results of samples (%, mass fraction)
Second, the beneficiation plan is determined
Because the independent nickel mineral in the test sample has only red arsenic nickel ore and orthorhombic arsenic ore, the content is very small, and the particle size is very fine, so it can not be enriched by mechanical beneficiation method. Only chemical beneficiation or smelting and enrichment method can be used. Extract nickel. The chemical beneficiation or smelting and enrichment methods of nickel oxide ore are divided into two major categories: fire method and wet method. The former is divided into smelting, nickel-iron method and granular iron method, and the latter has processes such as alkali method and acid treatment. The enrichment of nickel and ferronickel by fire method has high energy consumption, so the wet extraction of nickel has been paid more and more attention. The alkali method in the wet extraction of nickel can obtain a higher leaching rate, but most of them require pretreatment such as reduction and high temperature pressurization equipment. Acid leaching can easily obtain high leaching rate, and the ore does not need to be pretreated. Therefore, this study intends to study the ore sample by acid leaching.
Third, the experiment
(1) Test equipment and pharmacy
The test used XMQ2150×50 cone ball mill grinding, SENCO constant speed mixer and SENCOW201 constant temperature water bath; the test water was tap water, the test reagents were of analytical grade; the unit test sample weight was 270g.
(2) Leaching test conditions and procedures
Selecting the test agent specifically investigated Leaching Three sulfuric acid, nitric acid, hydrochloric acid leaching effect of the sample, a sample 270g test conditions, the grinding fineness 84% -0.074mm, stirring intensity 120r · min - 1, solid liquid ratio of 1: 5, changing the leaching agent type and amount are 1.7mol·L - 1, leaching agent at room temperature under three sulfuric acid, nitric acid, hydrochloric acid leaching optimum leaching agent screening 8h. The test flow is shown in Figure 1.
Figure 1 Basic process of leaching test
Fourth, the results and discussion
(I) Effect of the type and amount of leaching agent on the leaching rate of nickel From the test results, it is known that the leaching effect of sulfuric acid is the best among the three leaching agents of sulfuric acid, nitric acid and hydrochloric acid. The test results are shown in Fig. 2.
Figure 2 Leaching agent sulfuric acid dosage test results
FIG 2 shows that, in the sulfuric acid concentration is lower than 2.60mol·L - 1, the leachate with increasing grade nickel immersion in sulfuric acid concentration increases, the reaction rate will be increased in the leaching, but the concentration of sulfuric acid above 2.60mol·L - 1, the immersion in the nickel grade changes little, the leaching rate is not increased, so as to select the concentration of sulfuric acid leachant 2.60mol·L - as a subsequent test conditions.
(II) Effect of leaching slurry solid ratio on leaching rate of nickel
The concentration of test agent is fixed leaching 2.60mol·L - 1, with the increase of the leaching liquid to solid ratio, increase the amount of sulfuric acid leaching added. It can be seen from Fig. 3 that when the leaching slurry solid ratio is lower than 6:1, the leaching rate of nickel increases with the increase of the leaching slurry solid ratio, but when the leaching slurry solid ratio reaches 7:1 At this time, the leaching rate of nickel is no longer increased, so the leaching slurry solid ratio of 6:1 is selected as the subsequent test condition.
Figure 3 Test results of leaching slurry solid ratio conditions
(3) Effect of material fineness on leaching rate of nickel
As the grinding time increases, the finer the fineness of the leached material, the higher the nickel and iron content in the leaching solution, and the corresponding nickel leaching rate. However, increasing the fineness of the leached ore sample not only increases the grinding cost, but also makes the ore mill too fine in industrial production. When the leaching slurry is concentrated, the sedimentation speed becomes slower and even some of the fine ore particles are difficult to settle, which is not conducive to solid-liquid separation. It can be seen that from the two aspects of grinding cost and solid-liquid separation, the subsequent tests have the grinding fineness of -0.074mm and 78.60% as the test conditions.
(4) Effect of leaching time on nickel leaching rate
Leaching time is a non-negligible factor affecting nickel leaching. In principle, the longer the time, the higher the leaching rate of the elements in the material, but after the leaching reaction reaches the dissolution equilibrium, the elements are no longer dissolved.
It can be seen from Fig. 4 that as the leaching time increases, the leaching rate of nickel increases, but when the leaching time reaches 8h, the leaching rate of nickel changes little, and the concentration of nickel ions in the leaching solution is no longer The increase indicates that the leaching time reaches about 8h, the leaching reaction reaches the dissolution equilibrium, and the leaching time is no longer meaningful. Therefore, the leaching time of 8 hours is selected as the test condition in the subsequent test.
Figure 4 leaching time test results
(5) Effect of leaching temperature on nickel leaching rate
It is known from the test results that the increase of leaching temperature has little effect on the leaching rate of nickel, but temperature is an important factor affecting leaching, and the chemical reaction rate constant is exponentially related to temperature. Increasing the temperature is to increase the leaching speed and shorten the leaching time. Very beneficial.
It can be seen from Fig. 5 that the leaching temperature is 60 ° C, and the leaching effect at room temperature for 8 h can be achieved after leaching for 6 h, indicating that the leaching temperature is increased to improve the leaching speed of the leaching process, and the leaching temperature is maintained at 60 ° C. Conducive to the removal of impurity ions in the leachate. Therefore, considering the leaching rate of the main recovered metal nickel and the removal of the main impurity ion iron in the leaching solution, it is determined that the leaching condition temperature is 60 ° C for 6 h.
Fig. 5 Test results of leaching time conditions at leaching temperature of 60 °C
(6) One leaching repeatability test
From the above test results, the optimum process parameters for the leaching of sulfuric acid can be obtained. In order to verify the reliability of these parameters and the stability of the leaching, repeatability tests were carried out under these conditions. It can be seen from the data of the test results (Table 2) that the optimal process parameters determined by the conditional test are reliable, and the indexes of the leaching are also relatively stable, and the expected test results are achieved.
Table 2 Results of one leaching repeat test
(7) Effect of multiple leaching on leaching effect
It can be seen from the previous test results that the leaching effect can be obtained by leaching the laterite nickel ore with sulfuric acid as the leaching agent, but the nickel content in the primary leaching leaching solution is low, which is very disadvantageous for the subsequent preparation of nickel chemical concentrate. If evaporative concentration is used to increase the nickel content in the leachate, a large amount of heat energy is required. In order to save energy, it is considered to carry out the leaching of the leachate multiple times, that is, the leachate once leached is added to the next leached pulp to ensure leaching. The conditions were the same as in the first leaching, and the leaching was carried out several times in succession. The test results are shown in Table 3.
Table 3 Leachate multiple leaching test results
It can be seen from the data in Table 3 that the leaching solution is subjected to multiple leaching, and the Ni 2 + ions in the leaching solution are enriched. It is worth noting that since the leaching is carried out at 60 ° C, the Ni 2 + ions in the leaching solution are not simple. Multiple enrichment, it also contains a certain concentration of evaporation and enrichment. From the point of view of nickel immersion, after three times of leaching of the leaching solution, the concentration of Ni 2 + ions has reached the requirement of sinking nickel, further increasing the concentration of Ni 2+ ions (or repeated leaching after more than 3 times), iron and magnesium in the leaching solution. The content will also be enriched, and they will have an effect on the leaching of nickel. Therefore, considering the leaching rate factor, it is sufficient for the leaching solution to pass through three times of leaching.
V. Conclusion
1. The sample belongs to a nickel-nickel ore, and there are scattered nickel minerals. It is difficult to recover the nickel-cobalt resources by the general physical beneficiation method. The chemical leaching method is an effective means for developing and utilizing the resources.
2, chemical processing using sulfuric acid leaching process, the grinding fineness accounts for 78.60% -0.074mm, liquid to solid ratio of 6: 1, the concentration of sulfuric acid 2.60mol·L - 1, the stirring intensity 170r · min - leaching at 1, 60 deg.] C conditions At 6h, the leaching rate of nickel in the leaching solution was about 86%, and the leaching residue contained about 0.12% of nickel, and a good leaching index was obtained.
3. Multiple leaching tests show that the nickel ion concentration of the leaching solution is well enriched, but the content of iron and magnesium in the leaching solution is also enriched, which is unfavorable for the subsequent leaching solution. Considering various factors, the leaching solution is sufficient after three times of leaching.
references
[1] Zhu Jinghe. Technical Analysis of Development and Utilization of Nickelite Mine in the World[J]. Chinese Journal of Metals, 2007, (35): 22.
[2] Zhu Xun. China's mineral conditions. Volume II [M]. Beijing: Science Press, 1999.
[3] Tao Bingkun, Yin Xianming. The form and development countermeasures of nickel resources in China[J]. China Geology Economics, 1991, (10): 13.
[4] Zhang Youping, Zhou Yisheng, Li Yiyi, Li Weiguo.Characteristics of red earth mineral resources and pyrometallurgical process analysis[J].é“é“åˆé‡‘, 2007, (4) : 18.
[5] Yin Fei, Yan Shufeng, Jiang Peihai, Wang Chengyan, Chen Yongqiang.Experimental Study on Ammonia Leaching of Low-grade Laterite Nickel Ore Reduction Calcine[J].Mining & Metallurgy, 2007, (3) : 29.
[6] Xiao Zhenmin. Application of World Lateritic Nickel Mine Development and High Pressure Acid Leaching Technology[J]. China Mining Industry, 2002, 11(1): 56.
[7] Liu Yao, Zi Fan, Wang Dequan. Preliminary discussion on atmospheric pressure leaching of low grade nickel laterite ore[J]. Nonferrous Metals, 2007, (5) : 28.
[8] Liu Xue, Wen Jiankang, Yan Renman. Leaching of low-grade nickel oxide ore by fungal-derived organic acids[J]. Rare Metals, 2006,30 (4) : 490.
Author unit
School of Resources and Civil Engineering, Northeastern University (Che Xiaokui)
Institute of Mineral Resources and Metallurgy Materials, Beijing Research Institute of Nonferrous Metals (Che Xiaokui, Qiu Sha)
School of Civil and Environmental Engineering, University of Science and Technology Beijing (Che Xiaokui, Luo Xianping)
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