玉米秸秆和稻草-硫酸还原浸出低品位软锰矿

研究了以低品位软锰矿为原料,用玉米秸秆和稻草为混合还原剂,在硫酸介质中还原浸出锰的效果.通过单因素实验确定了玉米秸秆和稻草-硫酸还原浸锰的适宜工艺条件,该适宜工艺条件如下:软锰矿粒径为109μm,玉米秸秆和稻草的质量比为1∶1.5,玉米秸秆和稻草还原剂与软锰矿的质量比为3∶10,硫酸浓度为3.0 mol/L,液固比为10 m L/g,反应温度为90℃,反应时间为80 min.在适宜的浸出工艺条件下,软锰矿中锰的浸出率可达97%以上,锰的浸出效果较好.     

微波辅助预处理对玉米秸秆酶解的影响

研究了微波辅助硫酸、氢氧化钠预处理对玉米秸秆酶解糖得率的影响,并对温度、酸碱添加量、预处理时间、液固比4个因素进行了单因素试验分析。结果表明预处理的最佳条件为：微波-硫酸预处理时,温度190℃,硫酸质量浓度为10 g/L,预处理时间3 min,液固比20(硫酸体积(mL)与玉米秸秆质量(g)之比)条件下,预处理得糖率及酶解得糖率分别为44.6%和30.3%;微波-氢氧化钠预处理时,温度130℃,氢氧化钠质量浓度15 g/L,预处理时间7 min,液固比30(氢氧化钠溶液体积(mL)与玉米秸秆质量(g)之比)条件下,预处理得糖率及酶解得糖率分别为1.5%和80.0%。     

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%。     

废旧镍氢电池正极材料中镍和钴的回收

研究了在硫酸体系中回收废旧镍氢电池正极材料中的金属镍和钴. 用正交实验方法考察了浸出温度、浸出时间、硫酸初始浓度以及氧化剂用量对镍、钴浸出率的影响. 实验结果表明,各因素对镍和钴浸出率的影响程度排序均为:氧化剂用量>浸出时间>温度>硫酸初始浓度. 在实验得出的最佳浸出条件下,Co的浸出率为99.7%,Ni的浸出率为99.1%.     

某难处理多金属矿石综合浸出铀、铜、银试验研究

针对某难浸铀矿石,采用“氯化焙烧-硫酸浸出”工艺进行处理提取铀、铜、银。研究结果表明,最佳氯化焙烧实验条件为氯化钠用量6%,氯化焙烧温度 460 ℃,氯化焙烧时间2 h,焙烧液固比0.2∶1。对氯化焙烧后的矿样进行硫酸浸出,浸出条件为:硫酸浓度30 g/L、浸出时间30 min、浸出温度70 ℃、液固比2∶1,此时金属离子铀、铜、银的浸出率分别为铀85.08%、铜95.82%、银91.80%。     

预处理方法对细菌降解玉米秸秆产氢能力的影响

为提高细菌降解玉米秸秆产氢能力,实验研究了酸化汽爆预处理、硫酸预处理、氢氧化钠预处理和氨水预处理4种预处理方法对细菌Clostridium sp.X9降解玉米秸秆发酵产氢能力的影响.结果表明,酸化汽爆为最佳的预处理方式.在酸化汽爆预处理条件为硫酸体积分数1%、汽爆温度121℃和汽爆时间2 h时,纤维素降解产氢细菌Clostridium sp.X9利用酸化汽爆玉米秸秆产氢获得的最大产氢率和玉米秸秆降解率分别为6.4 mmol/g和47.8%.液相代谢末端产物主要为丁酸、乙酸和乙醇.     

镍钼矿提钼渣中镍的浸出工艺

在硫酸溶液中,使用常压氧化浸出法处理镍钼矿提钼渣以回收有价金属镍。考察搅拌速度、液固比、硫酸用量、氧化剂用量以及浸出时间对镍浸出过程的影响。试验结果表明:搅拌速度与液固比对浸出过程影响不明显;在未加入氧化剂时,主要发生镍氢氧化物简单的酸溶反应,而添加氧化剂后硫化物也被氧化浸出;此外,镍浸出率随浸出时间、温度及硫酸用量的增加而增大。最佳工艺条件如下:搅拌速度为500 r/min,液固比为4:1,氧化剂加入量为矿量的0.2倍,浸出温度为90℃,硫酸浓度为0.4 mol/L,浸出时间为8 h,镍浸出率可达95%左右。     

响应面法优化葡萄糖还原浸出半氧化锰矿的研究

采用响应面法优化葡萄糖还原浸出半氧化锰矿的工艺,以锰浸出率为响应值,对硫酸用量/矿量、葡萄糖用量/矿量、氟化铵用量/矿量和浸取时间四因素进行建模。结果表明,这些因素与锰浸出率的关系符合二次模型,各个因素对锰浸出率影响均极其显著,各个因素的二次方以及硫酸用量/矿量与葡萄糖用量/矿量的交互作用对锰浸出率影响较显著。最优工艺条件为：硫酸用量/矿量0.880 g/g、葡萄糖用量/矿量0.059 g/g、氟化铵用量/矿量0.04 g/g、浸取时间6 h。在此条件下,锰浸出率为93.09%,与模型预测值93.18%无显著差异,而相同条件下未加氟化铵的锰浸出率为82.37%。     

不锈钢酸洗污泥中重金属的浸出试验研究

采用无机酸作为浸出剂对不锈钢酸洗污泥中的重金属进行浸出,在相同条件下,各种酸的浸出效率顺序为：硫酸 >盐酸 >硝酸.讨论了硫酸浸出酸洗污泥时浸出时间、硫酸浓度、液固比和温度等条件对金属浸出率的影响.结果表明,硫酸浓度和液固比对镍铬的浸出率有较大的影响,而温度的影响较小.在液固比为6：1、温度为30℃、硫酸浓度为3 mol/L以及浸出时间为90 min的条件下,污泥中镍、铬、铁和锰的浸出率分别为99.3%,99.2%,99.8%和93.2%,残余污泥中镍铬含量符合排放标准.     

助溶酸浸硫铁矿烧渣的研究

采用常压下助溶酸浸的方法对提取硫铁矿烧渣中的铁进行了研究,得到硫铁矿烧渣中铁浸出率的影响因素及规律。结果表明,影响铁浸出率的主要因素为硫酸浓度、反应时间和温度、硫酸用量系数、助溶剂用量及热水用量;当硫酸用量系数为1.05、硫酸浓度为65%-70%、反应温度为125℃、反应时间为3-4 h、助溶剂用量为烧渣量的16%-20%、热水用量为烧渣量的1倍或1.8倍时,铁的浸出率可达95%以上。     

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.     

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%.     

Preparation of manganese sulfate from low-grade manganese carbonate ores by sulfuric acid leaching

In this study, a method for preparing pure manganese sulfate from low-grade ores with a granule mean size of 0.47 mm by direct acid leaching was developed. The effects of the types of leaching agents, sulfuric acid concentration, reaction temperature, and agitation rate on the leaching efficiency of manganese were investigated. We observed that sulfuric acid used as a leaching agent provides a similar leaching efficiency of manganese and superior selectivity against calcium compared to hydrochloric acid. The optimal leaching conditions in sulfuric acid media were determined; under the optimal conditions, the leaching efficiencies of Mn and Ca were 92.42% and 9.61%, respectively. Moreover, the kinetics of manganese leaching indicated that the leaching follows the diffusion-controlled model with an apparent activation energy of 12.28 kJ·mol-1. The purification conditions of the leaching solution were also discussed. The results show that manganese dioxide is a suitable oxidant of ferrous ions and sodium dimethyldithiocarbamate is an effective precipitant of heavy metals. Finally, through chemical analysis and X-ray diffraction analysis, the obtained product was determined to contain 98% of MnSO₄·H₂O.     

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.     

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.     

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.     

氧化铝赤泥酸浸提取镓的新工艺研究

研究了拜耳法赤泥硫酸浸出镓的过程。硫酸浸出镓的溶液,用氢氧化钠反应生成沉淀,再用盐酸溶解沉淀提取镓的过程。采用正交试验考察浸出过程中温度、时间、液固比、浓度对镓浸出率的影响的主次顺序以及最佳条件。结果表明,该方法比单纯用盐酸浸出镓的浸出率高。镓的高浸出率是保证高的回收率的基础。     

斑铜矿在酸性溶液中的浸出动力学行为

以斑铜矿为研究对象,在H₂SO₄酸性体系中,以NaS₂O₈为氧化剂,详细考察浸出时间、温度、矿物尺寸、液固比、H₂SO₄浓度和NaS₂O₈浓度对铜浸出率的影响.浸出行为表明,斑铜矿浸出动力学行为符合固体膜层的界面传质和扩散的混合控制,表观反应活化能为33.97 kJ/mol,浸出动力学方程为（ln(1-x)）/3-1+(1-x)^-1/3=k_mt.