【作者】 杨大锦；

【导师】 谢刚； 王吉坤；

【作者基本信息】 昆明理工大学 ， 有色冶金， 2006， 博士

【摘要】 锌具有广泛用途，锌表现出良好的市场需求和市场价格，我国锌冶金发展迅速。但由于锌冶金资源有限，导致锌冶金原料供应紧张。为保持锌冶金持续健康发展，必须开发利用各种锌原料，特别是丰富的低品位锌矿资源。低品位的锌矿资源的冶金方法比较多，但能经济、高效利用低品位锌资源的方法没有。要开发低品位锌矿的冶金新技术，才能实现低品位锌矿充分利用。我们对现有的锌冶金工艺进行对比分析后确定低品位锌矿的冶金工艺是堆浸→氧化中和除铁→萃取→反萃→有机相脱除→电积。在该工艺的研究中，创新地将堆浸法浸出低品位氧化锌矿、细菌浸出时采用混合细菌浸出、浸出液萃取前采用氧化中和除铁、中和净化液使用单一的P204萃取、萃取过程不进行中和游离酸（或不进行有机相的皂化处理）、反萃采用锌电积废液直接反萃和反萃液中的有机相用活性炭进行脱除等应用到低品位锌矿的提取冶金中。这些方法的应用，使低品位锌矿的冶金过程消耗降低，成本减少，形成了低品位锌矿的新的冶金工艺。低品位硫化锌矿使用就地采集培养的细菌，其能有效浸出硫化锌矿中的锌。细菌搅拌浸出、细菌柱浸和不同规模的堆浸结果表明，在细菌接种量10～20％，多次接种，浸出的pH=1.5～2.0，锌的年细菌浸出率大于80％。对细菌浸出过程规律的研究认为硫化锌矿中锌的浸出是细菌直接作用的结果，浸出过程中Fe³⁺作用不十分明显。低品位氧化锌矿中锌浸出性能好，采用堆浸工艺是可行的。堆浸周期在6个月以上，锌的堆浸浸出率大于90％。低品位锌矿的浸出液不能直接萃取锌，直接萃取时铁被萃取，使萃取剂再生工艺复杂，并产出大量的用途不大的废酸。合适工艺是氧化中和除铁后再萃取。用理论量的1.2倍工业二氧化锰、室温、2～3h和加石灰石作中和剂中和至终点的pH=5.1～5.3条件下就可使铁脱除率大于99％，溶液中铁的浓度在2mg／l以下。除铁过程中锌的损失率小于2.5％。除铁后液采用单一的P204进行萃取，合适的萃取有机相组成40％P204+60％煤油，萃取过程不中和产生的游离酸，也不对有机相进行皂化处理。萃取条件为室温、萃取级数为5～10级，混合时间5min，相比（A／O）为1～1.5：1，萃取终点pH=1.0左右，对于10～15g／l的溶液而言，锌的萃取率可达85～88％。萃取过程中萃取级数增加和有机相的增加（相比O／A增加）并不能明显增大锌的萃取率，提高萃取温度有利锌的萃取。萃取过程中，除铁以外的其它杂质基本上不被萃取，仅少量Co、Ni等的萃取也不影响锌的电积过程，并在电积中开路除去。锌的负载有机相可直接使用电积废液进行反萃。反萃级数3～5级，相比（A／O）为3～3.5：1，混合时间5min，用电积锌的废电积液（含硫酸135～150g／l）就能将97～99％的锌反萃下来，反萃后有机相含锌0.3g／l左右，杂质除铁外在有机相中没有富集，而进入反萃液中；负载有机相含锌＞12g／l时，反萃液中锌离子浓度增加大于40g／l，反萃液中的锌离子浓度为88～95g／l，游离酸70～75g／l。有机相与水相容易分离，分离澄清速度快。有机相中P204大于40％时容易产生乳化现象。有机相在溶液中溶解度随温度的升高而升高，随酸度的升高而降低。反萃液中溶解的有机相明显影响电积过程，造成阴极烧板，表面变黑，析出锌以粉末状形态存在，阴极表面不致密，阴极电积周期明显降低（低于14h），使锌电积过程最终不能正常进行。反萃液中有机相可采用活性炭吸附就完全消除有机相对电积的影响。+40目的活性炭的用量为40～80g／l时，基本消除有机相对锌电积的影响。脱除有机相后的反萃液与废电积液混合后进行电积可以获得1#以上的阴极锌。电积过程同极间距70mm，电积阴极电流密度500A／m²，牛胶加入量20mg／l左右时，电积周期24h，电积温度40℃时，电积的电流效率在89～92％，锌电积直流电耗3000度／吨锌左右。本论文主要创新点为：研究形成低品位锌矿全湿法的提取冶金工艺。低品位锌矿浸出过程采用硫酸堆浸工艺，浸出硫酸盐溶液采用氧化中和除铁，除铁后的硫酸盐溶液采用单一的P204萃取技术，萃取过程没有进行中和游离酸，反萃采用锌电积废液直接反萃，有机相采用活性炭进行脱除。更多还原

【Abstract】 Zinc and its compounds have wide-ranging usage because of their better physical and chemical properties, which leads to the rapid development of zinc metallurgy and gets favorable market ability and quotation. However, zinc metallurgy. has an inadequate supply for the lack of reserves. It is necessary to exploit all sorts of zinc reserves, especially resourceful low-grade zinc minerals to keep the sustaining and healthy development of zinc metallurgy. There have been many processes for extracting low grade zinc mineral reserves. Due to lack of methods which make these reserves be used economically and effectively at home, it is very important to develop new metallurgy techniques for these reserves and provide technical support of developing zinc metallurgy continually.The existing zinc metallurgy processes is comparative analysis, good process elicited to extract zinc from the low-grade zinc reserves is determined, which contains heap leaching→iron removal by oxidization and neutralization→solvent extraction→reverse-solvent-extraction→organic phase removal→electrolytic deposit in sequence.In this research, zinc can be leached availably from the low-grade zinc minerals by heap leaching and mixed bacteria leaching. Iron is removed from leaching liquor by oxidation and neutralization before extraction. The liquor after iron removed is extracted by single P204．During the extraction, free acid will not be neutralized and organic phase will not be saponification. Zinc electrodeposition scrap is reverse-extracted directly and organic phase is removed by activated carbon. With application of these new methods, consumption and cost reduce and new metallurgy technology of the low-grade zinc minerals is obtained.Zinc can be leached availably from the low-grade zinc by bacteria that have been gathered and cultured in situ. The results of bacteria agitation leaching, column leaching and heap leaching on different scales shows that bacterial leaching rate is more than 80% when the inoculums size of bacteria is 10～20%, inoculation many times and the leaching pH is 1．5～2．0．The investigation of the bacteria leaching process shows that zinc leaching from zinc sulphide ore is direct effect of bacteria and the effect of Fe³⁺ is not obvious. The low-grade zinc oxidized ore can be leached effectively by method of heap leaching. When the period of heap leaching is more than six months, the zinc leaching rate can be over 90%.Zinc cannot extract directly from the leaching liquor of low-grade zinc minerals. Iron will be extracted with direct extraction, resulting in the complicated regeneration technology of extractant and mass-produced waste acid. The appropriate process is that zinc is extracted when the leaching liquor oxidized and iron removed. In this process, the removal rate of iron is above 99% and the iron concentration in the liquor under 2mg/L under the condition: 1．2 times of the stoichiometric amounts of MnO₂ added, room temperature, 2～3 hours reaction time, limestone used for neutralize reagent added and the terminus pH of neutralization 5．1～5．3．The loss rate of zinc in this process is under2．5%.The liquor after iron removed is extracted by single P204．The appropriate extracting organic phase composition is 40% P204 and 60% kerosene. During the extraction, the free acid will not be neutralized and organic phase will not be saponification. The extraction rate of zinc is up to 85～88% for 10～15g/L zinc in liquor under the extracting condition: room temperature, 5～10 extraction stages, 5 minutes mixture time, 1～1．5:1 phase ratio A/O, and terminus pH about 1．0．The extracting rate of zinc is not increased obviously with the increasement of extracting stage and organic phase （with phase ratio O/A increasement）, and it is enhanced the zinc extraction as the extraction temperature increases.In the extracting process, all impurity except iron cannot be extracted. A few extractions of Co and Ni have no effect on electrolytic deposit process of zinc and can be removed in the electrolytic refining.Zinc with laden organic phase can be reverse-extracted using electrolyte scrap directly. The results indicated 97～99% zinc can be reverse-extracted by electrodeposition waste solution which contains sulfuric acid 135～150g/l under the condition: 3～5 reverse-extraction stages, 3～3．5:1 phase ratio （A/O） and 5minutes mixture time. The organic phase after reverse-extracted contains about 0．3g/l zinc ion, the impurities except iron do not rich in organic phase and come into reverse-extracting liquor. The concentration of zinc ion in the liquor will increase by over 40g/l, up to 88～95g/l and the concentration of free acid will be up to 70～75g/l when zinc concentration in the laden organic phase is over 12g/l.Organic phase can be separated easily from aqueous phase, which separate and defecate rapidly. Emulsification occurs easily when P204 concentration in the organic phase is over 40%. Solubility of organic phase in the liquor increases with the increasement of temperature, and reduces with the increasement of acidity.Organic phase dissolved in the reverse-extracting liquor has an obvious effect on electrodeposition process, which results in cathode burned and surface blacked, zinc precipitated in the form of a powdery state, the leaky cathode surface, the electrodeposition cycle of cathode reduced obviously less than 14 hours, and zinc electrodeposition process not operated normally in the ultimate. The effect of organic phase in reverse-extracting liquor on electrodeposition can be avoided completely with the adsorbing of activated carbon. There is basically no effect of organic phase on zinc electrodeposition process with activated carbon of 40～80 g/l dosage and a size distribution of +40 meshes.Reverse-extracting liquor removed organic phase mixing with electrodeposition scrap can product 1# cathode zinc. The following electrolytic condition is elicited from the experiments: 70mm homopolar distance, 500A/m² cathode current density, about 20mg/l isinglass dosage, 24 hours electrodeposition cycle, temperature 40℃, the electrical current efficiency is 89～92%, and consumption of direct current is about 3000 degrees per ton zinc.The main innovation point of this paper is that the wholly hydrometallurgy process of low-grade zinc minerals is investigated. The sulfuric acid heap leaching technique is used in low-grade zinc minerals leaching process. Iron is removed from leaching sulphate liquor by oxidation and neutralization. The sulphate liquor removed iron is extracted by single P204．Free acid is not neutralized in the extraction process. Zinc electrodeposition scrap is reverse-extracted directly. Organic phase is removed by activated carbon.更多还原