Reductive leaching of manganese from low-grade pyrolusite ore in sulfuric acid using pyrolysis-pretreated sawdust as a reductant

Manganese (Mn) leaching and recovery from low-grade pyrolusite ore were studied using sulfuric acid (H₂SO₄) as a leachant and pyrolysis-pretreated sawdust as a reductant. The effects of the dosage of pyrolysis-pretreated sawdust to pyrolusite ore, the concentration of sulfuric acid, the liquid/solid ratio, the leaching temperature, and the leaching time on manganese and iron leaching efficiencies were investigated. Analysis of manganese and iron leaching efficiencies revealed that a high manganese leaching efficiency was achieved with low iron extraction. The optimal leaching efficiency was determined to be 20wt% pyrolysis-pretreated sawdust and 3.0 mol/L H₂SO₄ using a liquid/ solid ratio of 6.0 mL/g for 90 min at 90℃. Other low-grade pyrolusite ores were tested, and the results showed that they responded well with manganese leaching efficiencies greater than 98%.     

Reductive leaching of low-grade manganese ore with pre-processed cornstalk

Cornstalk is usually directly used as a reductant in reductive leaching manganese. However, low utilization of cornstalk makes low manganese dissolution ratio. In the research, pretreatment for cornstalk was proposed to improve manganese dissolution ratio. Cornstalk was preprocessed by a heated sulfuric acid solution (1.2 M of sulfuric acid concentration) for 10 min at 80°C. Thereafter, both the pretreated solu-tion and the residue were used as a reductant for manganese leaching. This method not only exhibited superior activity for hydrolyzing corn-stalk but also enhanced manganese dissolution. These effects were attributed to an increase in the amount of reductive sugars resulting from lignin hydrolysis. Through acid pretreatment for cornstalk, the manganese dissolution ratio was improved from 50.14%to 83.46%. The pre-sent work demonstrates for the first time the effective acid pretreatment of cornstalk to provide a cost-effective reductant for manganese leaching.     

硫酸中香蕉皮还原低品位锰矿的浸出行为及动力学模型

Manganese was leached from a low-grade manganese ore (LGMO) using banana peel as the reductant in a dilute sulfuric acid medium. The effects of banana peel amount, H₂SO₄ concentration, reaction temperature, and time on Mn leaching from the complex LGMO were studied. A leaching efficiency of ~98% was achieved at a leaching time of 2 h, banana peel amount of 4 g, leaching temperature of 120°C, manganese ore amount of 5 g, and sulfuric acid concentration of 15vol%. The phase, microstructural, and chemical analyses of LGMO samples before and after the leaching process confirmed the successful leaching of manganese. Furthermore, the leaching process followed the shrinking core model and the leaching rate was controlled by a surface chemical reaction (1 ? (1 ? x)1/3 = kt) mechanism with an apparent activation energy of 40.19 kJ·mol?1.     

浸取环境对电解锰废渣中锰浸取的影响

在电解锰废渣中掺入锰矿粉,以提高锰废渣品位,探讨锰废渣中锰的硫酸法浸取回收效果.用单因素实验考察了矿渣比、液固比、浸取pH值、浸取温度和浸取时间等因素对锰浸取率的影响.实验结果表明,最佳浸取条件为：矿渣质量比3∶1、液固比3∶1（g/mL）、浸取液pH值2.0、浸取温度60 ℃和浸取时间3 h.最佳浸取条件下,锰浸取率达42.38%,与不加锰矿粉的浸取方法比较,锰浸取率提高了1.01倍.     

Reductive recovery of manganese from low-grade manganese dioxide ore using toxic nitrocellulose acid wastewater as reductant

The hydrometallurgical strategy of extracting Mn from low-grade Mn ores has attracted attention for the production of electrolytic manganese metal (EMM). In this work, the reductive dissolution of low-grade MnO₂ ores using toxic nitrocellulose acidic wastewater (NAW) as a reductant was investigated for the first time. Under the optimized conditions of an MnO₂ ore dosage of 100 g·L-1, an ore particle size of -200 mesh, concentrated H₂SO₄-to-NAW volume ratio of 0.12, reaction temperature of 90℃, stirring speed at 160 r·min-1, and a contact time of 120 min, the reductive leaching efficiency of Mn and the total organic carbon (TOC) removal efficiency of NAW reached 97.4% and 98.5%, respectively. The residual TOC of 31.6 mg·L-1 did not adversely affect the preparation of EMM. The current process offers a feasible route for the concurrent realization of the reductive leaching of Mn and the treatment of toxic wastewater via a simple one-step process.     

A primary study of simultaneous leaching of silver containing manganese ore and a sphalerite concentrate

It is demonstrated that a low grade, silver containing manganese deposit can be exploited by reaction with a ZnS concentrate. In the process, Mn（IV） is reduced to Mn（II） and the ZnS converted to ZnSO4. In the process, Mn and Zn are solubilized. By studying the effects of quantity of reducing agent and sulfuric acid added and of time, temperature and liquid-to-solid ratio on the leaching process, the optimum technological conditions have been achieved un- der which the amount of manganese leached was 98 %. The silver can be removed from remaining solids by adding ammonia liquor. Then by adding hydrazine hydrate, sponge silver with purity up to 99 % can be obtained with a recovery of 87 %.     

Extraction of Aluminum and Iron from Boiler Slag by Sulfuric Acid

This paper presents a new method of recycling aluminum and iron in boiler slag derived from plants that use coal as fuel. The new method integrates efficient extraction and reuse of the leached pellets together. An elemental analysis of aqueous solutions leached by sulfuric acid was determined by EDTA-Naz-ZnCl2 titration method. The components and microstructures of the samples were examined by means of XRF, XRD and SEM. An aluminum extraction efficiency of 86.50% was achieved when the sintered pellets were leached using 4 mol · L^- 1 H2SO4 at solid/ liquid [m（g）/V（mL）] ratio of 1 ： 5 at 80 ℃ for 24 h. An iron extraction efficiency of 94.60% was achieved in the same conditions for the maximum extraction efficiency of Al. The extraction efficiencies of Al and Fe increased with an increase in temperature, leaching time and acidity. The concentration of alumina and iron hydroxide in the final product was determined to be 99.12% and 92.20% respectively. This product of alumina would be used directly for the production of metallic aluminum.     

微生物燃料电池用于低品位锰矿浸提的研究

为提高低品位锰矿的利用,实现有机废水对锰矿物粉的浸提,通过改造微生物燃料电池(MFC),在阴极反应池中增加电解室及矿物质室,构建用于锰矿湿法浸提的MFC反应器,实现有机废水与锰矿物粉的还原氧化反应的分离。结果显示,以乙酸钠为碳源,以低品位锰矿粉为阴极的MFC输出电压最高可达0.81 V,是以K₃[Fe(CN)₆]为阴极液(0.631 V)的1.23倍。在相同条件下,矿物浸提MFC对COD的去除率可达90.9%,高于对照组(87.5%),而降解时间为3 d,显著少于对照组(5.2 d)。在降解COD能力的提升上,可实现对低品位锰矿粉中MnO₂的还原,其锰含量由原矿粉的23%降至0.98%,浸提率可达95.7%。进一步通过高通量测序对阳极端菌群结构进行分析发现,其主要菌群为地杆菌属(Geobacter),相对于对照组的85%,矿物浸提MFC中该属比例占总菌群的95%。结果表明,矿物浸提MFC可有效地将有机降解与矿物浸提耦合,避免两者直接混合反应带来的二次废水污染及浸提产物硫酸锰的净化问题,在提高MFC产电效率、处理废水的同时,实现对低品位锰矿的浸提。     

盐酸体系中二氧化锰浸出方铅矿的研究

在盐酸溶液中,用二氧化锰浸出方铅矿精矿制备氯化铅,并考察操作参数对铅浸出率的影响。研究结果表明盐酸体系中二氧化锰浸出方铅矿的最佳操作条件如下:搅拌速率为500 r/min,反应体系中总液体与总固体质量比为10,二氧化锰与方铅矿精矿质量比为1.3,反应时间为60 min,反应温度为80℃,盐酸浓度为3 mol/L,氯化钠质量浓度为250 g/L;在此最佳操作条件下,方铅矿精矿中的铅浸出率在99.5%以上,氯化铅产物纯度在99.6%以上。     

助滤剂对电解锰渣的助滤作用研究

针对锰渣滤饼含水率高的问题,通过在酸性浸出液中加入助滤剂来解决.通过酸性浸出液中锰渣的粒度,润湿性分析,发现锰渣粒度细和表面呈亲水性导致含水率高.根据锰渣的主要成分SiO₂和接触角试验,最后确定油酸酰胺、十八胺和十二胺作为助滤剂进行抽滤试验.结果表明:油酸酰胺对降低锰渣滤饼的含水率效果不佳,十八胺和十二胺效果显著.建立十八胺和十二胺用量对含水率作用的回归方程,确定十八胺用量为2514.47 g·m^-3时,含水率最低为36.10%,十二胺用量为1894.57 g·m^-3时,含水率最低为34.09%.因此,确定十二胺为锰渣的助滤剂.     

Alkaline pretreatment for chlorine removal from high-chlorine rhodochrosite

Chloride in manganese ore adversely affects mineral extraction. The mechanisms and the factors that influence an alkali pretreatment to removal chlorine from manganese ore were explored to eliminate hazards posed by chlorine during the electrolysis of manganese. The results showed that sodium carbonate, when used as an alkaline additive, promoted the dissolution of insoluble chloride, enhanced the migration of chloride ions, and effectively stabilized Mn2+. The optimal conditions were a sodium carbonate concentration of 0.45 mol·L-1, a liquid-solid ratio of 5:1 mL·g-1, a reaction time of 1 h, and a temperature of 25°C. The chlorine removal efficiency was greater than 95%, and the ore grade (Mn) was increased by 2.7%.     

玉米秸秆还原浸出高铁低品位锰矿研究

采用"玉米秸秆硫酸预处理—浸出"工艺处理含Mn 9.63%(质量分数)的朝阳锰矿.通过试验考察用硫酸对玉米秸秆进行预处理的时间、秸秆用量、温度、硫酸浓度和浸出温度对锰浸出率的影响.试验表明,在秸秆用量2.5 g、时间10 min、硫酸浓度1.2 mol/L、温度80℃时预处理秸秆,浸出温度为90℃的条件下,锰的浸出率达92%,杂质铁溶出率仅为20%.玉米秸秆处理前后FTIR分析结果表明,对秸秆进行硫酸预处理能够破坏难降解的木质素结构,有利于提高锰的浸出效果.     

利用工业废盐酸与低品位菱锰矿生产氯化锰的试验研究

介绍了以工业废盐酸和低品位菱锰矿为原料制取氯化锰的工艺研究.通过对酸浸过程的理论与试验研究,讨论了各种因素对锰浸出率及产品质量的影响,得出最佳工艺条件.试验结果表明,在反应温度为80℃、液固比2.5:1、酸的过量系数1.3、时间60min条件下锰浸出率为90%左右,氯化锰产品质量符合HG/T 3816-2006标准要求.     

用硫酸亚铁浸出同时沉淀铁矾法处理低品位锰矿

研究了用硫酸亚铁浸出同时沉淀黄钠铁矾的方法处理低品位软锰矿的过程．在该过程中,软锰矿中的ＭｎＯ２被还原成ＭｎＳＯ４同时ＦｅＳＯ４被氧化并以黄钠铁矾的形态沉淀．沉淀产生的酸可直接用于ＭｎＯ２浸出．考察了硫酸、硫酸亚铁和硫酸钠的加入量及温度等参数对锰浸出和沉铁效率的影响．讨论了过程动力学．实验结果表明,锰浸出率和沉铁效率（质量分数）在最佳条件下可分别达到９６％和９２％．     

Synthesis and X-ray crystal structure of a new manganese 18-metallacrown-6

0　IntroductionThemetalionsinmetallamacrocylesformedbysupramolecularself assemblycantaketrigonal,square planar,andtetrahe dralconfiguration[1 ,2 ] .Metallacrownisaspecialclassofmetalla macrocyle,theyareanalogoustocrownethersinbothstructureandfunctionexceptthatthemetalionsarenowtakingthepositionsofcoordinationatomsincrownether[3,4] .Themetallacrownswithdifferentnumberof [M—N—O]repeatunithavedifferentcavitysizes,suchas 9 MC 3[5 7] ,12 MC 4 [4,8 1 4 ] and 15 MC 5 [1 5] .Thereportedazameta…     

芦丁还原浸出低品位软锰矿的研究

为了研究糖蜜酒精废液中有机物还原浸出软锰矿的机理,采用芦丁为还原剂,在酸性介质中直接浸出低品位软锰矿。通过正交实验和单因素实验,研究了芦丁浓度、硫酸浓度、反应温度、浸出时间等因素对锰浸出率的影响,并对反应过程机理进行了初步探讨。实验结果表明,影响锰浸出率的主要因素依次为反应温度、硫酸浓度、浸出时间和芦丁浓度;当硫酸初始浓度2.35 mol/L,芦丁初始浓度0.041 mol/L,反应温度90℃,浸出时间90 m in时,锰浸出率达94.9%。     

同槽电解生成锰和二氧化锰

分别采用预电解法,Mn(NO₃)₂热解,热解-预电解方式制备MnO2覆层Ti电极,并分别作为电解二氧化锰的阳极,硫酸锰-硫酸为电解液,研究不同的电流密度、温度、酸度对电解二氧化锰电流效率的影响.研究表明：采用热解-预电解法制备的Ti-MnO₂电极,抗钝化能力强,表面致密,MnO₂覆层与Ti基结合牢固,适合作为电解阳极使用.采用盐桥,素烧瓷,玻璃纤维作为阴阳极隔膜,阳极采用上述Ti-MnO₂电极,使用经过抛光的不锈钢作为阴极,在同一电解槽中同时电解生成电解MnO₂和金属锰,较佳条件下阳极和阴极电流效率分别能达到90%和60%,产品符合质量要求.     

Efficient and selective recovery of Ni,Cu, and Co from low-nickel matte via a hydrometallurgical process

Low-nickel matte was intensively characterized, and Ni, Cu, and Co were determined to exist mainly as (Fe,Ni)₉S₈ and FeNi₃, Cu₅FeS₄, and (Fe,Ni)₉S₈ and Fe₃O₄ (in isomorphic form), respectively. The efficient and selective extraction of Ni, Cu, and Co from the low-nickel matte in an (NH₄)₂S₂O₈/NH₃·H₂O solution system was studied. The effects of (NH₄)₂S₂O₈ and NH₃·H₂O concentrations, leaching time, and leaching temperature on the metal extraction efficiency were systematically investigated. During the oxidative ammonia leaching process, the metal extraction efficiencies of Ni 81.07%, Cu 93.81%, and Co 71.74% were obtained under the optimal conditions. The relatively low leaching efficiency of Ni was mainly ascribed to NiFe alloy deactivation in ammonia solution. By introducing an acid pre-leaching process into the oxidative ammonia leaching process, we achieved the high extraction efficiencies of 98.03%, 99.13%, and 85.60% for the valuable metals Ni, Cu, and Co, respectively, from the low-nickel matte.     

菱锰矿酸浸过程杂质行为

对菱锰矿酸浸过程的Ｆｅ，Ａｌ，Ｓｉ等杂质的溶解行为进行了研究，并用扫描电镜和能谱对其反应机理进行了验证．结果表明：在适当的试验条件下，Ｓｉ及大部分Ｆｅ，Ａｌ并不被酸溶解，而是形成残留物层包裹在尚未反应的颗粒表面上．     

Deep cleaning of a metallurgical zinc leaching residue and recovery of valuable metals

Huge quantities of zinc leaching residues (ZLRs) generated from zinc production are dumped continuously around the world and pose a potential environmental threat because of their considerable amounts of entrained heavy metals (mainly lead). Most ZLRs have not been properly treated and the valuable metals in them have not yet been effectively recovered. Herein, the deep cleaning of a ZLR and recovery of valuable metals via a hydrometallurgical route were investigated. The cleaning process consists of two essential stages:acid leaching followed by calcium chloride leaching. The optimum conditions for extracting zinc, copper, and indium by acid leaching were a sulfuric acid concentration of 200 g·L-1, a liquid/solid ratio of 4:1 (mL/g), a leaching time of 2 h, and a temperature of 90℃. For lead and silver extractions, the optimum conditions were a calcium chloride concentration of 400 g·L-1, a pH value of 1.0, a leaching time of 1 h, and a temperature of 30℃. After calcium chloride leaching, silver and lead were extracted out and the lead was finally recovered as electrolytic lead by electrowinning. The anglesite phase, which poses the greatest potential environmental hazard, was removed from the ZLR after deep cleaning, thus reducing the cost of environmental management of ZLRs. The treatment of chlorine and spent electrolyte generated in the process was discussed.