【作者】 陈进中；

【导师】 杨天足；

【作者基本信息】 中南大学 ， 冶金工程， 2012， 博士

【摘要】 本文对脆硫铅锑矿的处理、高锑低银铅阳极泥的传统处理工艺现状、立方晶型锑白的制备等进行了全面的综述。针对目前高锑低银铅阳极泥处理工艺存在的问题,提出采用控制电位氯化浸出—蒸发浓缩—连续蒸馏方法处理高锑低银铅阳极泥,以制备立方晶型锑白,并进行了实验研究。采用同时平衡原理,对三氯化锑浸出液中PbCl2、AgCl溶解度进行详细的热力学分析,从理论上论证了氯盐体系中铅锑分离和锑银分离的可行性和合理性。绘制标准状态下不同体系中E—lg[Cl]T图、氯化铅的溶度积与lg[Cl]T的关系图和不同锑浓度下氯化铅的溶解度曲线,以及氯化银的溶度积与lg[Cl]T的关系图和不同锑浓度下氯化银的溶解度曲线。结果表明：难溶盐PbCl2只在一定的氯离子浓度范围内才能稳定存在。当体系中锑的浓度不断增加,难溶盐PbCl2稳定存在的氯离子浓度范围有所增大,铅溶解度也随之降低,铅溶解度小于0.005mol/L的总氯浓度范围不断扩大,可有效实现铅锑分离。同样地,难溶盐AgCl只在一定的氯离子浓度范围内才能稳定存在。当体系中锑的浓度不断增加,难溶盐AgCl稳定存在的氯离子浓度范围有所增大,银溶解度也随之降低,银溶解度小于0.00001mol/L的总氯浓度范围不断扩大,可有效实现银锑分离。采用控制电位氯化浸出—浓缩—连续蒸馏方法处理高锑低银铅阳极泥,以制备立方晶型锑白,并进行了详细的实验研究。研究结果如下：1、浸出液采用氯化钠可以除去91%的氟硅酸根离子,采用浓缩方法在蒸发温度为120℃时可进一步除去溶液中的硅和氟。2、控制电位氯化浸出过程中溶液的电位高低决定浸出渣的物相,控制溶液电位在430mV以上,浸出渣中主要以PbCl2和AgCl存在,无单一贱金属的峰发现,而控制溶液电位在380mV以下,浸出渣中还存在金属锑单一物相。在控制溶液电位在450mV的条件下,阳极泥中的金属银和铅被氧化后大部分是以AgCl (S)和PbCl2(S)的形式沉淀于浸出渣中,有少部分以配合物的形态进入溶液,还有部分银以金属态存在于浸出渣中。3、采用铅阳极泥还原浸出液中的高价锑离子,还原过程温度为80℃,还原时间为2h,铅阳极泥中的金属可还原氯化浸出液中的五价锑离子,还原后液中五价锑的含量仅为0.60g/dm3,而阳极泥中呈氧化态的锑被氯化浸出液中的盐酸溶解浸出而进一步提高溶液中的锑含量。采用蒸发浓缩的方法可将氯化浸出液加热至120℃使其中的硅化合物基本蒸发出来,以防止其在后续连续蒸馏过程中蒸发,在冷凝过程结晶,堵塞冷凝器管道,影响蒸馏过程的进行。蒸发冷凝过程结晶物的主要成分是无定形水合二氧化硅。还原液冷却结晶产物的主要成分是氯化银和氯化铅,还原液经自然冷却降温处理,氯化银和氯化铅的溶解度大幅下降,可进一步富集铅和银,提高铅和银的直收率。4、浸出液的连续蒸馏过程的生产能力取决于蒸馏速度,蒸馏速度随蒸馏负压增加而逐渐增大；蒸馏速度随着蒸馏温度的升高而降低。砷蒸馏率随一次蒸馏温度升高而增加,砷的蒸出量在135-150℃温度区间内达到最大,当温度达到180℃时,砷的蒸出率仍只有95.2%。二次减压蒸馏产品三氯化锑纯度已达99.94%,杂质含量很低,符合化学试剂级产品质量,三氯化锑的蒸馏率达99.0%以上。5、当氯氧锑中和转化反应溶液中存在酒石酸铵时,pH下降速度变慢,而存在EDTA时,pH急剧下降。在酒石酸根离子存在的情况下,氯氧锑在中和转化为单一的立方晶型锑白。而在EDTA存在的情况下,中和转化为斜方晶型锑白。当n(Sb):n(C4H4O62-30:1时,中和转化产物呈八面体结构,而且菱角分明。锑白的白度和成分达到国家产品标准要求。6、铅银渣采用碳酸盐转化、硅氟酸浸、氨水浸银以及水合肼还原处理,银以银粉回收,直收率和总回收率分别为97%及98.12%；铅以硅氟酸铅溶液回收补充铅电解精炼贫化的铅离子,铅直收率及总回收率分别为86.26%及99.12%。蒸馏残渣采用盐酸浸泡,盐酸酸浸液可分步水解回收锑和铋,将盐酸酸浸液加水水解,先水解沉淀氯氧锑,所得氯氧锑返回控制电位氯化浸出系统进行回收；再将水解母液用稀氨水溶液调节pH值进一步水解成氯氧铋；而中和水解母液则经铁粉置换可回收海绵铜。该工艺是可行的,可回收了蒸馏残渣中的有价金属铜、锑和铋。回收率均在95%以上。7、从高锑低银类铅阳极泥制备锑白的锑总回收率达98%以上,试验重现性比较好。伴生金属铅和银主要分布在浸出渣、还原液冷却结晶产物和蒸馏残渣中,三者总和均达100%。而铋、铜等则主要富集在蒸馏残渣中,分别为99.04%和98.16%。砷则主要富集在连续蒸馏馏出液中,占90.42%。需经济合理综合考虑稀盐酸的回收处理得到的盐酸浓度与浸出过程中投入盐酸浓度两者的关系。更多还原

【Abstract】 In this paper, the traditional treatment status of jamesonite, lead anode slime bearing high antimony and low silver and preparation of Cubic antimony white have been general summarized. The technology of preparing cubic antimony white from lead anode slime bearing high antimony and low silver by potential-controlled chloridization leaching, distilling concentration and continuous distillation has been proposed.The relationship of [Pb2+][Cl-]2-lg[Cl]T, E-lg[Cl]T in Pb-Sb-Cl-H2O system were studied and the solubility of lead chloride at different antimony concentrations was calculated both based on principle of simultaneous equilibrium. The results showed that insoluble salt PbCl2would only exist stably in a certain concentration range of chlorine ion. The solubility of Pb2+in the solution decreases with increasing of the concentration of antimony in the system, whereas increases with increasing of the concentration of total chlorine. The concentration range of total chlorine causing lead solubility less than0.005mol/L is ever-expanding. This concentration range of chlorine ion expands a little with increasing of the concentration of antimony in the system while narrows as the system acidity increases.Similarly, insoluble salt AgCl only stably exist at a certain concentration range of chloride ions. When the concentration of Sb in the system continuously increased, this concentration range of chlorine ion in which insoluble salt PbCl2existed stably expanded, but the solubility of Ag in the solution decreased. And the concentration range of total chlorine expanded continually corresponding solubility of silver less than0.00001mol/L, which meant separating the Ag and Sb was feasible. These study provided a theoretical basis for the separation of lead and antimony, silver and antimony in Sb-Cl-H2O system. As a result, the feasibility and an efficient way for separating these two kinds of metals were discussed and indicated, respectively.The technology of preparing cubic antimony white from lead anode slime bearing high antimony and low silver by Potential-controlled chloridization leaching and continuous distillation was studied in detail. Experimental results were showed as following.1. The removal ratio of silicofluoric ion in leaching solution is about91%by the addition of NaCl. Si and F in leach liquor can be further removed when distillation temperature is120℃by distilling concentration.2. The solution potential in the process of leaching process includes three stages:In the first stage, the solution potential increases slowly; In the second stage, there are no obvious change in the solution potential, so a plateau emerges in the potential-time curve; In the third process, the solution potential increases greatly. The length of plateau in the second stage decreases with increasing the concentration of Sb3+or the temperature. The phase of leached residue is determined by the solution potential. When the solution potential is controlled greater than430mV, there is mainly AgCl and PbCl2existed in the leached residue, when the potential is controlled under380mV, the metal Sb is also existed in the leaching residuum besides the AgCl and PbCl2. Therefore, the optimum potential of solution is430mV, the leaching rates of Sb, Bi and Cu are greater than98%, the leaching rate of Pb and Ag are3.10%and2.34%respectively.3. In the chloridization leaching process, Sb5+was reduced with lead anode slime at80℃for two hours, then the content of Sb5+is only0.60g/dm3in the reduced solution. At the same time, Sb2O3in lead anode slime was dissolved by hydrochloric acid in chloridization leaching solution, the content of Sb in the reduced solution will increase. Using, silicon compound can be distilled out basically with distilling concentration, when the reduced solution is heated to120℃. The removal of silicon compound is beneficial to the subsequent continuous distillation; it can solve the problem of pipe plug brought out because of the crystallization of these substances during the evaporation and cooling process. The major component of crystallization is amorphous hydrated silicon dioxide at the distilling concentration process. And the major components of cooling and crystallizing are AgCl and PbCl in the distillation mother solution, and solubility of AgCl and PbCl are decreased when the distillation mother solution is cooled at the atmosphere. So it can be recycled due to the high degree of enrichment.4. Production capacity of the continuous distillation is depended on distillation speed. Distillation speed gradually increases with the increasing of distillation negative pressure, and it will decrease with the increasing of distillation temperature. The distillation ratio of As increases with the increasing the first step distillation temperature. Arsenic distillation ratio is more than70%at130℃, but arsenic distillation ratio is still less than90%at130℃. The quantity of distilled arsenic is the most at the rage of135℃to150℃, so arsenic distillation ratio is only95.2%at180℃. Purity of trichloride antimony is up to99.94%at the second step distillation. The content of impurity in the trichloride antimony is lower, The SbCl3reach the level of the reagent completely, the distillation ratio of trichloride antimony is more than99.0%.5. pH decreases slowly when ammonium tartrate exists in the neutralized transformation solution. But it decreases fast when there is EDTA in the neutralized transformation solution. When tartrate ion exists in the neutralized transformation solution, antimony chloride was transformed into single cubic antimony white. And when EDTA exists in the neutralized transformation solution, antimony chloride is transformed into rhombic antimony white. When n(Sb):n(C4H4O62-)=30:1, the product presents a octahedron structure and its edges and corners are clearly. The whiteness and component of antimony white are all up to the national product standard.6. The residue bearing Pb and Ag was transformed into by carbonate, then lead in the transformed residue was leached with silicofluoric acid, and Silver was leached with ammonia, finally silver powder was recovered while silver ion was reducer by hydrazine hydrate. The recover ratio and overall recover ratio of silver are97%and98.12%, respectively. Lead was recovered to return to the electrowin system with lead fluosilicate. The recover ratio and overall recover ratio of lead are86.26%and99.12%, respectively.The distillation residue is soaked by hydrochloric acid. The soak solution will be hydrolyzed to recover Sb and Bi by step. The soak solution was hydrolyzed by adding water, the precipitation of Sb4O5Cl2was returned to the leaching system. pH of the hydrolyzed mother solution was adjusted by using ammonia to obtain BiOC1. Moreover, copper powder is recovered from neutralizing hydrolysis mother solution with replacement of iron powder. This process was feasible and the valuable metals, such as copper, antimony and bismuth can be recovered. The recovery rates of the valuable metals are more than95%separately.7. The recover rate of Sb is up to98%in the process of preparing antimony white from lead anode slime bearing high antimony and low silver. The experiment result was reappear well. Co-existed metals, such as Pb, Ag, was distributed in the leached residue, the crystallized product of cooling reducing solution and the distillation residue mostly, the sum of above all reach100%.99.04%of Bi,98.16%of Cu in the anode slime were enriched in the distillation residue respectively. And90.42%of As in the anode slime was enriched in the continuous distillate. It needs to considerate economically and reasonably that the relationship between concentrations of HC1which is recovered from dilutes hydrochloric acid and concentration of HC1as a leach solution into the leaching process.更多还原