【作者】 杨长江；

【导师】 张旭；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2004， 硕士

【摘要】 金川公司海绵铜是镍电解过程中的净化渣，由于含有一定数量的铜、镍硫化物，用常规的方法不易经济处理。本文综述了大量硝酸在冶金中应用的文献，并在金川公司前期试验的基础上，针对其铜的组成主要为金属铜和硫化铜的特点，提出了一种全新的处理工艺——氧气低压催化氧化法。该法在密闭体系条件下，采用低压氧气(0～400mmHg)和硝酸催化氧化浸出海绵铜生产优质硫酸铜。该工艺在金川公司进行了半工业试验，结果表明：铜浸出率为99.36-99.94％，镍的浸出率94.73-99.85％；金属铜，尤其是硫化态铜，浸出完全，金属损失少；硫大部分以元素硫的形态析出，滤渣含硫70.28％，部分硫转化为硫酸。作为催化剂的硝酸回用率可达到70％以上；产出的硫酸铜达到工业一级硫酸铜标准；浸出成本明显较硫酸化焙烧-浸出工艺低。前者的吨硫酸铜直接加工成本为166.10元，后者达到1302.17元。 本文在对过程进行理论分析的基础上，对工艺进行了机理和工艺的改进研究。 铜的氧化研究采用旋转铜圆盘法，发现铜的氧化溶解分为两种情况，钝化氧化和活化氧化；在钝化氧化溶解时，钝化与溶液酸度、硝酸根浓度、温度、搅拌速度等相关；氢离子浓度小于4mol／l时，铜的溶解具有明显的钝化特性，如在0.1M时，溶解速率为：2.262mg／(l·min)；硝酸根离子的变化对铜溶解影响很小，铜的浓度变化与硝酸根离子浓度近似呈线性关系，斜率为：1.916mg／mol；随温度的增高，钝化速度加快，在90℃时，30min即到钝化态；在钝化氧化溶解阶段，增加转速并不能加快溶解，只能使其快速达到钝化阶段；实验证实硝酸氧化过程中，亚硝酸起到关键作用；此时氯离子的加入有利于铜的氧化。对于铜的活化氧化溶解，本文提出了硝酸氧化的自催化反应历程，经实验结果验证，理论与实验符合较好；依据反应历程得到了反应初期和转移期的反应方程式；在转速为300rpm时，测得了铜氧化溶解的表观活化能E_a=23.221kJ／mol，介于典型的外扩散控制(8～16kJ／mol)与化学反应控制(40～200kJ／mol)之间，反应为混合控制。在此基础上得出铜氧化浸出的较佳工艺条件为：溶液硫酸浓度为8mol／l，硝酸1.5mol／l，温度80℃，搅拌强度300转／分。 在一氧化氮吸收的研究中发现：高温下吸收有利于溶液中形成硝酸，但是不利于动力学上NO的氧化，而后者为氮氧化物吸收过程的主要控制步骤。因此应在昆明理工人学硕十学位论文摘要低温下进行氮氧化物的吸收，在高温下进行亚硝酸的转化:高酸度有利于硝酸的生成;常温常压下吸收达到合理的终点时，硝酸浓度达到4.79m。l/l(26%wt)，完全可以回用。 铜氧化与吸收的联合试验表明:铜氧化和氮氧化物吸收可以有效联合进行，不存在操作性问题;过程中氮氧化物的吸收完全可以满足要求，大量的硝酸在反应器内部就得以再生，大量的减少了硝酸用量:同时，硝酸的再生分布可以调节气体循环速度加以人为控制。 对于硫酸铜的精制，试验找到一个较高生产效率和较低能耗的方法。粗硫酸铜经过洗涤、重溶、重结晶，粗硫酸铜中游离酸的脱除率在98%之上;产品质量:CuS。，，SHZo)98%:比50。蕊0.1%;水不溶物〔0.1%，达到国家优等品的指标。 通过对硝酸在铜氧化过程中的作用、氮氧化物的吸收的研究，以及实验室试验和半工业试验，为处理金川公司海绵铜渣工业化生产提供了一条经济合理的途径，并可望为硝酸在冶金及相关工业中的应用提供一个基础。更多还原

【Abstract】 The sponge copper is a kind of purring scraps which is produced in the nickel electrolyzing in Jinchuan Non-ferrous Metal Company(JNMC). Present on the application of nitric acid on metallurgy in recent years at home and abroad are reviewed on base of studying a lot of papers and books. A new hydrometallurgical process for conversion of the sponge copper derived copper and copper sulfide into bluestone crystal is provided basing on the previous experiments carried out by both JNMC and. Kunming University of Science and Technology. The process comprises: oxidation of copper, absorption of nitric oxide, refining of copper sulfate. Oxygen and nitric acid are used as oxidation and catalyst, respectively. During the leaching process,the pressure of vessel is less than 400mmHg. The results of the plant scale test are showed below: the leaching ratio of copper is 99.3-99.94%, nickel 94.73-99.85%; The contain of sulfur in the residue is 70.28%, and the result means most of sulfur in sulfide is oxygenated into elemental sulfur; The product of copper sulfate accords with the China top industrial standard; Oxygen is utilized to oxidize gaseous NOx to regenerate nitric acid, and more than 70% of nitric acid is recoverable. Economic analysis showed that the process had a lower operation cost ( 166.10 per ton copper sulfate), as compared to the Sulfuric Acid Roast Leaching processes ( 1302.17 per ton). Process and mechanism were been researched after the plant test. Oxidation of copper is researched by the rotating disk method. The oxidation of copper includes the passivation oxidation and the activation oxidation. The effects of oxidation time, temperature, agitation speed, concentration of nitric acid and sulfuric acid, chlorine ion, nitrous acid in the leaching solution are discussed. In addition, the mechanism of activation oxidation is suggested. The reaction rate is calculated, and the formula is accorded with the data of experiments. The oxidation of copper is a self-catalyzed reaction. The nitrous acid is active mid-product. All the phenomena occurring in the plant scale can be explained with the mechanism. The apparent activation energy for activation oxidation of copper is determined as 23.22KJ/mol at 300 rpm. It means a mixture controlling procedure. The optimal condition for oxidation of copper are: sulfuric acid 392g/l, nitric acid 1.5mol/l,temperature 80 C, agitation speed 300rpm. Absorption of nitric oxide is studied in a experimental device which simulates the reactor in the plant scale test. It is founded that high temperature is of advantage to form nitric acid, but that is disadvantageous to the oxidation of nitric oxide in dynamics. However, the latter is the determination step of the absorption process. So nitric oxide should be absorbed in low temperature. The higher the acidity of the absorption solution, the higher ratio of nitric acid forms. The concentration of nitric acid in absorption solution can reach 4.79mol/l, which is high enough to be reused as oxidant. Combining experiment of oxidation and absorption proves that the oxidation of copper and absorption of nitric oxide can be carried out at the same time effectively. The distribution of nitrate between oxidation and absorption reactor can be controlled by the circulating speed of gas. An excellent refining method for bluestone is given. It can save more water and energy than the traditional evaporation method. Through washing, re-dissolving, re-crystal, the removal rate of dissociation sulfuric acid is more than 98%. Quality of the product: CuSO4-5H2O 98%;H2SO4 0.1%; un-dissolved substance 0.1%, reaches the China top industrial standard. During the lab and plant scale test, a powerful and regenerable oxidant, nitric acid, is utilized to completely ( 99%) leach copper and nickel from the copper sponge. The result of this paper is significant not only to JNMC, but also to be utilized in some metallurgy processes using nitric acid.更多还原