Sulfuric acid leaching of high iron-bearing zinc calcine

Sulfuric acid leaching of high iron-bearing zinc calcine was investigated to assess the effects of sulfuric acid concentration, liquid-to-solid ratio, leaching time, leaching temperature, and the stirring speed on the leaching rates of zinc and iron. The results showed that the sulfuric acid concentration, liquid-to-solid ratio, leaching time, and leaching temperature strongly influenced the leaching of zinc and iron, whereas stirring speed had little influence. Zinc was mainly leached and the leaching rate of iron was low when the sulfuric acid concentration was less than 100 g/L. At sulfuric acid concentrations higher than 100 g/L, the leaching rate of iron increased quickly with increasing sulfuric acid concentration. This behavior is attributed to iron-bearing minerals such as zinc ferrite in zinc calcine dissolving at high temperatures and high sulfuric acid concentrations but not at low temperatures and low sulfuric acid concentrations.

Pressure leaching of zinc silicate ore in sulfuric acid medium

Zinc silicate ore was characterized mineralogically and the results showed that zinc exists mainly as hemimorphite and smithsonite in the sample.Sulfuric acid pressure leaching of zinc silicate ore was carried out to assess the effect of particle size,sulfuric acid concentration,pressure,reaction time and temperature on the extraction of zinc and the dissolution of silica.Under the optimum conditions employed,up to 99.25% of zinc extraction and 0.20% silica dissolution are obtained.The main minerals in leaching residue are quartz and small amounts of undissolved oxide minerals of iron,lead and aluminum are associated with quartz.

Extraction of metals from a zinc smelting slag using two-step procedure combining acid and ethylene diaminetetraacetic acid disodium

A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium (EDTA-Na2) was applied to extract metals such as Cd,Cu,Fe,Pb and Zn from a zinc smelting slag. The results show that the extraction rates of Cd,Cu,Fe and Zn in slag reach 88.3%,54.1%,69.6% and 54.7%,respectively,while the extraction rate of Pb is only 0.05% leached with 1.25 mol/L sulfuric acid under the conditions of the ratio of slag to liquid of 100 g/L,65 °C and 120 r/min for 2 h. However,Pb extraction rate from 1.25 mol/L sulfuric acid leached residue reaches as high as 66.5% by using 0.1 mol/L EDTA-Na2 solution. The results indicate that two-step sequential extraction procedure combining 1.25 mol/L sulfuric acid and 0.1 mol/L EDTA-Na2 solution can extensively extract Cd,Cu,Fe,Pb and Zn from zinc smelting slag.

Pressure acid leaching of zinc sulfide concentrate

Effects of particle size of the zinc sulfide concentrate,leaching temperature,solid-to-liquid ratio and additive amount on pressure acid leaching process of the zinc sulfide concentrate were studied.The results indicate that the additive can improve the reaction kinetics and the conversion rate.And sulfur can be successfully separated from the zinc sulfide concentrate as elemental sulfur.The reasonable experiment parameters are obtained as follows:the leaching temperature 150℃,oxygen partial pressure 1 MPa,additive amount 1%,solid-to-liquid ratio 1:4,leaching time 2 h,initial sulfuric acid concentration 15%,and particle size less than 44μm.Under the optimum conditions,the leaching rate of the zinc can reach 95%and the reduction rate of the sulfur can reach 90%.

Study on experiment and mechanism of thermal dissolved sulfuration of low grade lead-zinc oxide ore in lanpin

The thermal dissolved sulfuration technology is brought forward and performed based on the characteristic of low grade lead-zinc oxide ore in lanpin. Using sulfur as the sulphidizing agent in the experiment, the oxides in the sandstone and ignimbrite are changed into sulfides. The disproportionation reaction of sulfur in a solution is confirmed as 4S＋3H2O=2S^2-＋S2O3^2--＋6H^＋. The dynamics process is studied and the first-order reaction rate equation -1n（1-a）=ktt is obtained. The effects of the reactive products, stirring speed, dosage of sulfuration agent, value of pH and sulphidizing temperature on the sulfuration of oxide ore are investigated. The results indicate that the reactive apparent activation energy is 100.8 kJ/mol and the sulfuration ratio of lead-zinc oxide ore reaches 60% under the conditions of pH 5.9-7.5, the sulfuration temperature of 130 ℃, sulfuration time of 180 min and the stirring speed of 800 r/min.

H_(2)SO_(4)/ZnCl_(2)复合活化微波法制备污泥活性炭研究

以城市剩余污泥为原料,H_(2)SO_(4)和ZnCl_(2)为复合活化剂,采用微波法制备污泥活性炭,研究微波活化温度、功率、辐照时间及固液比对污泥活性炭碘吸附值影响,并利用TG、BET、FTIR、SEM等对产物进行表征。结果表明:当固液比1∶1.5、微波功率2000 W、活化温度600℃和辐照时间20 min时,污泥活性炭碘吸附值最高约为1360 mg·g^(-1)。与干污泥相比,加活化剂干污泥的热解仍为3个阶段,但半焦生成焦炭阶段的失重有较大提高,污泥活性炭的比表面积约为331 m^(2)·g^(-1),表面可见大小不一且未被堵塞的孔洞,平均孔径约为13 nm,有相对较多的含氧官能团。

锌精矿氧压浸出技术研究进展

传统湿法炼锌工艺存在烟气处理成本高、综合回收率低等问题,近年来,氧压浸出技术因其原料适应性强、锌回收率高、环境污染小等优点被应用于锌冶炼工业。介绍了锌精矿氧压浸出的生产工艺,论述了浸出过程反应的基本原理,以及离子催化、温度、酸度、分散剂等条件对浸出过程离子行为的影响与机理。讨论了锌精矿中伴生元素铁、镓、锗、铟、银等的浸出行为及在不同浸出条件下浸出行为的变化。

从铁矾渣侧吹熔炼—烟化法烟灰中回收锌镉及其净化除杂

研究了采用酸性浸出—硫化除杂法从铁矾渣侧吹熔炼—烟化法产出的烟灰中回收锌、镉,并选择性除去浸出液中的铜,产物用以制备镉掺杂硫化锌;在热力学分析基础上,探明了硫酸体系下锌浸出率影响因素及其浸出动力学;通过正交试验明确了各参数对硫化钠选择性除杂的影响。结果表明:烟灰中锌主要以氧化锌形式存在,其浸出过程符合混合控制,表观活化能为73.70 kJ/mol;在最佳条件下,锌浸出率达98.99%。以Na_(2)S用量为理论添加量的3.2倍,控制体系pH=2.0,铜去除率可达95.97%,同时有效保留锌、镉,实现了铜与锌、镉的选择性分离。

对位芳纶端基结构分析的MALDI-TOF MS方法的建立与优化

采用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)对对位芳纶的端基结构进行分析。以3-氨基喹啉为基质,三氟乙酸钾为离子化剂,采用蒸发研磨法(E-G)制备了测试样;为了获得具有较高信噪比的对位芳纶MALDI-TOF MS图,对基质与分析物比例进行优化,重点分析了少量残余硫酸对质谱结果的影响。结果表明:在反射模式下,样品制备选择基质/分析物比例为20:1可获得较佳的质谱信号;样品中含有少量硫酸能够改善分析物与基质的结晶效果,减少脱羧作用的发生,降低氨基碎片丢失的几率,使得H/Na和H/K交换现象发生的几率降低,从而改善质谱信噪比,提高分析可靠性。

湿法炼锌污酸处理中石膏渣减量化工艺探索

针对目前湿法炼锌中采用石灰中和法处理污酸产生的石膏渣量较大的问题,本文提出采用锌焙砂-碳酸钙两段中和法处理硫化后液的工艺并进行试验。该工艺通过锌焙砂中和部分酸,再采用碳酸钙进行中和,将氟除去的同时减少污酸石膏渣产量。实验结果表明,采用锌焙砂中和时,控制pH值为2.0~2.5,在温度35℃条件下中和1 h,沉降过滤后采用碳酸钙进行二段中和,控制终点pH为5.0~5.5,反应1 h,沉氟后液含氟量小于20 mg/L,沉氟率超过98%,产出石膏渣仅为传统石灰中和法所产石膏渣量的24.94%,溶液经过除氯后可返回湿法系统中。

用稀硫酸-有机酸体系浸出锌粉置换渣中的锗试验研究

研究了用稀硫酸-有机酸体系从锌粉置换渣中回收锗。采用单因素试验探讨了锌粉置换渣中锗的浸出行为规律。考察了硫酸初始质量浓度、温度、浸出时间、液固体积质量比和有机酸种类及添加量对锗浸出率的影响。结果表明:在硫酸初始质量浓度70 g/L、温度55℃、浸出时间1 h、液固体积质量比10 mL/1 g、酒石酸加入量10 g/L和搅拌速度300 r/min条件下,锗、铜、锌浸出率分别为95.6%、96.8%和95.1%。该法为锌粉置换渣中锗的回收利用提供了一种新途径。

铜、锌离子浓度比对羟基乙叉二膦酸体系电镀黄铜的影响

以羟基乙叉二膦酸(HEDP)为配位剂进行电镀黄铜(Cu–Zn合金),通过阴极极化测试、循环伏安分析、扫描电镜(SEM)观察、X射线衍射(XRD)等手段研究了Cu^(2+)/Zn^(2+)浓度比对电沉积过程及镀层微观结构的影响。结果表明,HEDP体系中Cu–Zn合金电沉积的电位介于Cu和Zn之间。随Cu^(2+)/Zn^(2+)浓度比减小,Cu–Zn合金的初始沉积电位正移,共沉积得到促进,镀层的Zn质量分数增大。Cu^(2+)/Zn^(2+)浓度比为1:4时所得Cu–Zn合金镀层为金黄色,微观上呈均匀分布的胞状结构,镀层中Cu的质量分数在65%~70%之间,与氰化物电镀黄铜的组成最接近。

铅锌冶炼污酸处理新工艺半工业化试验研究

介绍了一种高效率、短流程的硫化处理铅锌冶炼污酸的新工艺,分别从高效硫化除砷和铊、制取石膏、石膏压滤液回收锌等方面进行了全流程半工业化试验。结果表明,高效硫化除砷、铊效率高,硫化滤液中砷离子质量浓度低于0.1 mg/L、铊离子质量浓度低于2μg/L,硫化反应过程无H2S气体逸出;二段硫化产出的锌渣中锌质量分数达到55%左右,可进行火法冶炼回收锌;所产石膏渣经毒性浸出检测鉴定为一般固废,无中和渣产出;二段硫化滤液可满足GB 25466—2010《铅、锌工业污染物排放标准》规定的特别排放限值要求。

石墨炉原子吸收法测定湿法炼锌含锌中间物料中铊含量

铊及其化合物有剧毒,在湿法炼锌工艺生产过程中存在环境污染风险,但是湿法炼锌过程中间物料中铊的存在形态复杂,含量低且不稳定,造成湿法炼锌过程含铊中间物料中铊的跟踪监测与检测较为困难。本文利用铁盐及硫酸-溴化钾萃取富集消除复杂基体成分对铊测定的干扰,使Tl^(3+)与Br^(-)形成的[TlBr_(4)]^(-)配阴离子被甲基异丁基甲酮(MIBK)定量萃取后形成离子配合物,进行有机相中铊的测定。通过优化仪器测定条件,确定石墨炉灰化温度400℃,原子化温度1650℃,从而实现对锌冶炼工艺含锌中间物料中铊元素含量的准确测定。方法的检出限为0.27μg/L,RSD<10%,加标回收率为95.2%~102.6%,分析结果经与ICP-MS检测数据对比,结果准确可靠。

锌精矿高压釜硫酸浸出条件下的表面活性剂及其混合物:表面活性剂选择和实验室测试

通过浸出实验和对浸出产物的粒度、相成分等的后续分析研究表面活性剂及其混合物对锌精矿加压浸出效果的影响。所用表面活性剂为木质素磺酸盐(Lignosulfonate,LS)和十二烷基硫酸钠(sodium dodecyl sulfate,SDS)。通过测量表面张力研究表面活性剂对人工模拟溶液表面活性的影响。结果表明,同时添加LS和SDS具有协同效应,导致表面张力降级。在一系列加压浸出实验中,研究表面活性剂及其混合物浓度(СLS/SDS=0.2~0.8 g/L)、温度(T=120~140℃)、氧分压(pO_(2)=0.5~0.7 MPa)和时间(t=20~120 min)等参数对溶液中锌、铁、铜和铟浸出效果的影响。根据研究结果确定的锌精矿浸出的最优参数为:СLS=0.6~0.8 g/L、СSDS=0.2~0.6 g/L、pO_(2)=0.5 MPa、T=140℃和t=100~120 min。在最优条件下溶液中的锌、铟、铜和铁的浸出率分别为93%~94%、65%~66%、64%~68%和48%~49%。

某铜铅锌多金属碳酸盐型氧化矿的硫酸浸出试验研究

研究了用硫酸从刚果(布)某铜铅锌多金属碳酸盐型氧化矿中浸出铜,考察了加酸方式、酸矿比、浸出温度、初始矿浆浓度、矿石粒度对铜浸出率的影响。结果表明:在室温、浸出时间2 h、酸矿比140 kg/t、初始矿浆浓度27.5%、矿石粒度P80=105μm条件下采用三段递减加酸法浸出铜,铜浸出率达92.19%,浸出效果较好。

含锌尘泥火法挥发的次氧化锌制备硫酸锌研究

为了实现含锌尘泥的高值化利用,本文以含锌尘泥火法处理挥发得到的次氧化锌为原料,开展了硫酸浸出次氧化锌制备硫酸锌的研究。结果表明:在硫酸质量分数为22.42%、浸出时间为20 min、液固比为2.5∶1、搅拌速度为300 r/min的条件下,滤渣中Zn质量分数由61.17%降低至2.61%,Pb质量分数由5.86%提高至34.24%,硫酸锌溶液中Zn离子质量浓度高达243.01 g/L,Pb离子质量浓度降低至1.50 g/L;试验得到的硫酸锌溶液在结晶温度为20℃,结晶时间为60 min条件下,得到纯度大于99%的硫酸锌产品,且该产品满足饲料添加剂硫酸锌的质量标准。

不同因素对含硫酸废水处理固废热分解效果的影响

从某污水处理厂收集含硫酸废水,对其进行处理后得到固体废物。设计实验,分别选取反应温度、反应时间、碳与硫的摩尔比、添加剂这4个因素来探究其是否对固废热分解效果产生影响。结果表明,反应时间、反应温度、碳与硫的摩尔比这3个因素对固废样品的热分解效果有显著影响,有无添加剂对于单位反应物产气量的影响并不明显。采用正交设计,分析各因素不同组合下的固废热分解效果,得到当反应温度为900℃、反应时间为50 min、碳与硫的摩尔比为3.5∶1时,硫酸钙的还原率最高,分解较为彻底。

再生铜烟尘硫酸浸出铜、锌试验研究

文章研究了硫酸浸出再生铜烟尘中的铜、锌,考察了浸出温度、硫酸用量、反应时间、液固比对铜、锌浸出率的影响。试验结果表明:浸出温度是影响再生铜浸出铜、锌的主控因素,其次是硫酸用量,次之是反应时间,影响最小的是液固比;通过单因素条件试验得到最佳浸出条件是浸出温度60℃、硫酸用量为理论硫酸用量的1.2倍、反应时间2 h、液固比5∶1,在此条件下再生铜烟尘铜、锌浸出率分别为91.32%、98.21%。

艾萨炉炼铅烟尘氧压浸出工艺研究

采用氧压浸出工艺从艾萨炉炼铅烟尘中高效浸出锌、镉,研究了氧压浸出温度、初始硫酸浓度、氧压浸出时间、氧气压力、液固体积质量比对锌、镉浸出率的影响。结果表明,在初始硫酸浓度为40 g/L,液固体积质量比为3 mL/g,氧压浸出温度为120℃,氧压浸出时间2.0 h,氧气压力为0.6 MPa,搅拌速度为600 r/min的条件下,锌、镉浸出率分别为72.19%、96.95%。