【作者】 朱福良；

【导师】 华一新；

【作者基本信息】 昆明理工大学 ， 有色金属冶金， 2003， 博士

【摘要】 广西自治区盛产的铅锑复杂硫化矿是我国主要炼锑原料之一。铅锑复杂硫化矿的现有生产工艺主要采用火法工艺流程，其主要缺点是铅锑分离不彻底，铅锑在冶金过程中反复循环，铅锑回收率低，大部分锑在生产过程中循环，精锑质量差，产品一般是4号锑，甚至只能产出高铅锑。铅锑分离一直是处理这种矿石的技术难题。本文针对现有工艺的不足，采用水蒸气-空气混合气氛氧化新工艺对这种矿石进行处理，利用水蒸气能选择性氧化挥发三硫化锑，从而一步实现铅锑两种金属的有效分离，分别产出铅精矿（焙砂）和锑精矿（烟尘），并把贵金属富集在焙砂中，显著地提高了金属的综合回收率，而且不消耗任何试剂，可以使传统的铅锑复杂硫化矿冶炼流程大为简化，是对铅锑复杂硫化矿处理技术的创新。 本文系统地完成了水蒸气-空气混合气氛氧化挥发焙烧铅锑复杂硫化矿的小型实验和公斤级实验研究，确定了直接从铅锑复杂硫化矿进行铅锑分离的最佳工艺参数，并采用SEM、EDAX、XRD、DTA-TG和化学分析等分析检测手段，从热力学和动力学两个方面研究铅锑复杂硫化矿及其主要组元的相关体系（PbS-Sb₂S₃、PbS-Sb₂S₃-FeS、PbS-Sb₂S₃-ZnS、PbS-Sb₂S₃-FeS-ZnS等）与水蒸气反应的基本规律，得出了一系列重要结论。利用FACT Sage 5.0数据库，绘制了Me-S-O-H系的优势区图，指出了在水蒸气焙烧的氧势和硫势范围之内各金属的存在形态。并采用固定化学势法（Constrained Chemical Potential Method）计算了Pb-S-O-H、Sb-S-O-H体系的气相平衡组成，绘制了主要气相物种的等压图。具体研究结果如下： 1、工艺实验证明采用水蒸气氧化挥发焙烧铅锑复杂硫化矿是可行的，能够有效地实现铅锑分离。小型实验得出的最佳工艺条件为：温度973～1023K；水蒸气流量1800～2500ml/min；空气流量200～300ml/min；试料粒度2～3mm；焙烧时间120～150分钟。在以上工艺条件下，具有以下综合指标：产出的焙砂中，含铅36～40％，含锑＜2％，焙砂中铅的直收率＞95％；产出的烟尘中，锑含量＞51％；铅含量为1.5～3.2％，烟尘中锑的直收率＞94％；焙砂中的含硫量为3～6％，脱硫率大于85％。 公斤级实验的最佳工艺条件为：焙烧温度973～1023K；水蒸气流量35.32L/min；空气流量6L/min；试料粒度3～5mm；焙烧时间180min；床层厚铅锑复杂硫化矿铅锑分离的理论和新工艺研究国家自然科学基金项目度13.33mm。在以上工艺条件下，具有以下综合指标:产出的焙砂中，含铅31一35%，含锑3.22一6.34%，焙砂中铅的直收率>97%;铅锑分离产出的烟尘中，锑含量70.41一75.07%，铅含量<1.5%;烟尘中锑的直收率达到85%。 2、水蒸气一空气混合气氛焙烧铅锑复杂硫化矿的机理研究结果表明，铅锑复杂硫化矿水蒸气氧化焙烧能有效地实现铅锑分离，其最根本的原因是水蒸气能催化分解铅锑复杂硫化矿中的脆硫铅锑矿（FePb4Sb6S，4），使其分解成各种铅、锑、铁的简单硫化物（SbZS3、PbS、FeS）。在相同的温度下，分解出的SbZS3由于其饱和蒸气压远远大于PbS的饱和蒸气压，SbZS3对PbS的分离系数刀Sb7s，一PbS>>1，因此SbZS3将优先挥发进入气相。在气相中的SbZS3又能被水蒸气选择性地氧化成SbZO。，因此气相中SbZS3始终保持较低的分压，使SbZS3的挥发过程达不到平衡状态，从而促进了SbZS3的挥发。而硫化铅不与水蒸气发生任何化学反应，并且由于其自身饱和蒸气压较低，在焙烧过程中基本不挥发，保留在残渣中。这样，就可以实现铅锑的有效分离。在惰性气氛中，脆硫铅锑矿能够发生分解，但分解得很不彻底，铅锑分离效果较差。而在空气或氧气气氛下，脆硫铅锑矿（FePb4Sb6S，4）会转变成较稳定的复杂氧化物FePb4Sb3O13，使锑的挥发变得困难，这是现行氧化挥发焙烧方法不能有效分离铅锑的主要因素。 水蒸气氧化焙烧铅锑分离的动力学研究表明，当温度<IO23K时，铅锑分离过程主要受化学反应控制，其表观活化能为85.92kJ/mol;当温度之IO23K的时候，化学反应阻力与内扩散阻力相比可以忽略不计，此时反应速率主要受内扩散控制，相应的表观活化能为10.27kJ/mol。 3、PbS一SbZS3、PbS一SbZO3、PbO一SbZS3、PbO一SbZO3等体系与水蒸气反应的对比实验表明，PbS一SbZS3二元系与水蒸气反应后焙砂中主要由PbS组成，同时还含有少量的SbZO3，铅锑分离效果较好。PbS一SbZO3二元系与水蒸气反应后焙砂中的主要物相为PbS，没有观测到含锑的物相，铅锑分离效果最好。而PbO一SbZS:和PbO一SbZO:这两个含有PbO组成的试样与水蒸气反应以后，焙砂的物相组成比较复杂，都含有稳定的铅锑氧的化合物（PbsbOZ、Pb5Sb4O，，、PbsbZO6），焙砂中锑的含量较高，达不到理想的铅锑分离效果。PbO和SbZO3能形成稳定的化合物，这是导致铅锑分离效果不好的主要原因。这四个二元系在水蒸气气氛下的铅锑分离效果好坏的顺序为:PbS一SbZO3>Pbs一SbZS3>PbO一SbZS3>PbO一SbZO3。从这可以看出，当氧势高到可以生成PbO的时候，铅锑分离效果不好;在氢气气氛下的挥发实验证明，若氧势太低，试样中铅锑都保持硫化物的状态，铅锑分离效果也更多还原

【Abstract】 Pb-Sb complex sulfide ores, mainly distributed in Guangxi Zhuang antonomous region, are important resources of lead and antimony in China. Presently these complex ores are treated by pyrometallurgical process. Although it has some advantages, its major disadvantages are inferior Pb-Sb separation result, low direct recoveries of Pb and Sb, and meaningless recycle of Pb and Sb in the smelting process. The existing pyrometallurgical flowsheet usually produces low-quality antimony or even lead-antimony alloy. So the Pb-Sb separation is a key problem in treating this kind of Pb-Sb complex ores. An innovative lead-antimony separation technology for Pb-Sb complex sulfide ores by oxidation and volatilization roasting with steam-air mixtures has been developed in this paper. Experimental results show that the complex ores are successfully separated into lead and antimony concentrates, respectively. The precious metals are concentrated in the roast. The technology developed has advantages over the existing process in: more satisfying comprehensive recoveries of metals, more simple separation process and less quantity of flux.Laboratory and kilogram-scale tests of roasting process of Pb-Sb complex sulfide ores with steam-air mixtures have been carried out systematacially. The optimum parameters for Pb-Sb separation have been determined. The mechanisms of reaction between the systems (PbS-Sb2S3, PbS-Sb2S3-FeS, PbS-Sb2S3-ZnS and PbS-Sb2S3-FeS-ZnS) and steam have been investigated thermodynamically and kinetically using SEM, EDAX, XRD, DTA-TG and chemical analysis. The sulfur-oxygen potential diagrams for Me-S-O-H systems have been plotted by employing Fact Sage 5.0 database. The behavior of the sulfides and oxides of interest has been investigated. The equilibrium constituents of the Pb-S-O-H and the Sb-S-O-H systems in vapor phase have been calculated by Constrained Chemical Potential Method (CCPM). The computational results are plotted in Gibbs triangles.1. The lead-antimony separation technology for Pb-Sb complex sulfide ores by oxidation and volatilization roasting with steam-air mixtures is proved to be highly effective. The optimum parameters for laboratory test are determined as: temperature 973-1023K, steam flow rate 1800~2500ml/min, sample size 2~3mm and roasting time 120-15Omin. Under optimum conditions, the roast contains 36-40% Pb and <2% Sb, and the dust 50-75 Sb and <3% Pb. The direct recoveries of Pb and Sb are >94% and >93%, respectively. The content of sulfur in the roast is 3-6% and the desulfurization efficiency is greater than 85%.The optimum experimental conditions for kilogram-scale test are obtained as follows: roasting temperature 973-1023K, steam flow rate 35L/min, air flow rate 6L/min, roasting time 180min, sample size 3~5mm, bed thickness 13.33mm. With the above parameters, the roast contains 32.68-39.78% Pb and <3.22% Sb. The dust contains 69.65-75.07% Sb and <1.5% Pb. The direct recovery of Pb is greater than 95% and that of Sb is up to 85%.2. The mechanisms of the novel technology for treating Pb-Sb complex sulfide ores have been investigated. In steam atmosphere, the results indicate that the reaction of Pb-Sb complex sulfide ores with steam can promote the Pb-Sb separation. The reason is that steam can decompose the jamesonite (FePb4Sb6Si4) and the complex intermediate products into simple sulfides of lead, antimony and iron. At the same temperature, the saturated vapor pressure of the Sb2S3 is higher than that of PbS and separation coefficient is much greater than 1. So, Sb2S3 will be preferentially volatized into vapor phase and PbS enriched in the roast. Besides Sb2S3 in the vapor phase can be selectively oxidized by steam into Sb2O3. As a result, the partial pressure of Sb2S3 in the vapor phase will be reduced and the volatilization of Sb2S3 will be promoted. In contrast, in inert atmosphere, the jamesonite (FePb4Sb6S14) can beVIdecomposed into single sulfides to some extent only. The remaining jamesonite brings the hindrance to volatilization of Sb更多还原