Optimization of the Dissolution of Tincal Ore in Phosphoric Acid Solutions at High Temperatures

The aim of the study was to investigate the optimization of the dissolution of tincal ore in phosphoric acid solutions at high temperatures in a batch reactor. The effect of the following parameters on the dissolution process was investigated: the reaction temperature, the phosphoric acid concentration, the particle size, and the solid-to-liquid ratio. The best conditions for the dissolution were determined using the 2⁴ factorial experimental design method. The optimum values of the parameters were experimentally determined. The effective parameters were the reaction temperature, the phosphoric acid concentration, the particle size, and the solid-to-liquid ratio. The optimum conditions resulted in the maximum boron dissolution at an acid concentration of 1 M, reaction temperature of 85°C, particle size of 4.75 mesh, and solid-to-liquid ratio of 1/6 g · mL^?1. Under these optimum conditions, the best dissolution yield was 98.26%.     

OPTIMIZATION OF LEACHING OF COPPER FROM OXIDIZED COPPER ORE IN NH3-(NH4)2SO4 MEDIUM

Studies were carried out for selective leaching of Cu with simultaneous avoidance of iron dissolution during leaching of oxidized copper ore in an aqueous NH₃-(NH₄)₂SO₄ system. The effects of leaching parameters, such as ammonia concentration, ammonium sulphate concentration, leaching time, and solid-to-liquid ratio, were investigated on leaching of copper. A 2ⁿ factorial experimental design method in the dissolution experiments was used. In addition, the “Steepest Ascent” method was also applied to determine the optimum leaching conditions. It was observed that the most effective parameters on the leaching of copper were ammonia concentration and leaching time. Only 0.17% of iron in ore was dissolved in ammonia and ammonium sulphate medium. The optimum conditions established for maximum copper recovery were: ammonia concentration 2.824 mol L^?1, ammonium sulphate concentration 0.236 mol L^?1, solid-to-liquid ratio 0.167 g mL^?1, leaching time 2 h. Fixed parameters chosen in the experiments were: room temperature, average particle size 2.8 mm, stirring speed 500 rpm. Under the optimum conditions established for maximum copper recovery, the percentage of leached copper was 98.87.     

Determination of the Optimum Conditions for Copper Leaching from Chalcopyrite Concentrate Ore Using Taguchi Method

The optimum conditions for the extraction of copper from chalcopyrite concentrate into SO₂-saturated water were evaluated using the Taguchi optimization method. High level copper recovery was obtained in an environmentally friendly process that avoids sulfur dioxide emission into the atmosphere because SO₂ forming in the roasting is used in the dissolution. Experimental parameters and their ranges were chosen as follows: reaction temperature, 293–333 K; solid-to-liquid ratio, 0.025–0.15 g/mL; roasting time, 30–90 min; roasting temperature, 773–973 K; stirring speed, 400–800 rpm; and reaction time, 10–60 min. The particle size and gas flow rate were 63 µm and 10 cm³/min, respectively. The optimum conditions of the dissolution process were determined to be reaction temperature of 318 K, a solid-to-liquid ratio of 0.025 g mL^?1, a roasting time of 75 min, a roasting temperature of 773 K, a stirring speed of 400 rpm, and a reaction time of 30 min. Under optimum conditions, dissolution yield of copper was 91%.     

OPTIMIZATION OF LEACHING OF COPPER FROM OXIDIZED COPPER ORE IN NH3-(NH4)2SO4 MEDIUM

Studies were carried out for selective leaching of Cu with simultaneous avoidance of iron dissolution during leaching of oxidized copper ore in an aqueous NH₃-(NH₄)₂SO₄ system. The effects of leaching parameters, such as ammonia concentration, ammonium sulphate concentration, leaching time, and solid-to-liquid ratio, were investigated on leaching of copper. A 2ⁿ factorial experimental design method in the dissolution experiments was used. In addition, the “Steepest Ascent” method was also applied to determine the optimum leaching conditions. It was observed that the most effective parameters on the leaching of copper were ammonia concentration and leaching time. Only 0.17% of iron in ore was dissolved in ammonia and ammonium sulphate medium. The optimum conditions established for maximum copper recovery were: ammonia concentration 2.824 mol L^-1, ammonium sulphate concentration 0.236 mol L^-1, solid-to-liquid ratio 0.167 g mL^-1, leaching time 2 h. Fixed parameters chosen in the experiments were: room temperature, average particle size 2.8 mm, stirring speed 500 rpm. Under the optimum conditions established for maximum copper recovery, the percentage of leached copper was 98.87.     

Investigation of selective leaching and kinetics of copper from malachite ore in aqueous perchloric acid solutions

In this study, the leaching kinetics of malachite in perchloric acid solutions was investigated. The dissolution behaviors of copper, zinc, and iron in the ore matrix were determined at different acid concentrations and reaction temperatures. It was observed that the concentration of perchloric acid had a major effect on the dissolution of copper, zinc, and iron. It was determined that the effect of temperature on the dissolution of these species was not as significant as concentration impact. The results obtained shown that copper in the ore matrix was completely leached while zinc and iron were partially dissolved in perchloric acid solutions. In addition, the effects of the acid concentration, reaction temperature, stirring speed, particle size, and solid-to-liquid ratio on the leaching of malachite were researched. In these experiments, it was observed that the leaching rate of copper increased with increasing solution concentration, stirring speed, and reaction temperature, and with decreasing solid-to-liquid ratio and particle size. A kinetic analysis was performed, and it was found that the rate of leaching reaction obeyed the mixed kinetic control model in the unsteady state. The activation energy of the leaching process was calculated to be 34.69 kJ/mol.     

硫铁矿烧渣酸浸铜反应动力学研究

研究了硫酸烧渣的硫酸浸铜过程中,搅拌速率、浸出剂初始质量浓度、固液比、浸出温度和矿物粒径对浸出率的影响,并对硫铁矿烧渣浸取铜过程动力学进行了分析。研究结果表明,该浸出过程符合收缩芯模型,与化学反应控制动力学方程式相吻合,浸出反应的表观活化能为39.19 kJ/mol,浸出过程控制步骤为化学反应控制。     

Dissolution kinetics of ulexite in acetic acid solutions

Ulexite is an important boron mineral used for the production of boron compounds. The aims of this study are to examine the dissolution kinetics of ulexite in acetic acid solutions, and to present an alternative process to produce boric acid. In order to investigate the dissolution kinetics of ulexite in acetic acid solutions, the concentration of solution, reaction temperature, solid-to-liquid ratio, and particle size were selected as experimental parameters. It was determined that the dissolution rate of ulexite increased with increasing solution concentration and temperature and decreasing particle size and solid-to-liquid ratio. The activation energy of the process was found to be 55.8 kJ/mol.     

Determination of the Optimum Conditions for Leaching of Malachite Ore in H2SO4 Solutions

The Taguchi method has been used to determine the optimum conditions for the dissolution of malachite ore in H₂SO₄ solutions. The chosen experimental parameters and their range were (i) reaction temperature: 15 to 45 °C, (ii) solid‐to‐liquid ratio: 1/10 to 1/3 g cm^–3, (iii) acid concentration (in weight): 2 % to 10 %, (iv) particle size: –40 to –3.5 mesh, (v) stirring speed: 240 to 720 rpm, and (vi) reaction time: 5 to 45 minutes. The optimum conditions were found to be reaction temperature: 40 °C, solid‐to‐liquid ratio: 1/3 g cm^–3, acid concentration (in weight): 10 %, particle size: –30 mesh, stirring speed: 480 rpm, and reaction time: 45 minutes. Under these optimum working conditions, the dissolution of copper and iron in malachite ore was 100 % and 58 %, respectively. Besides, alternative working conditions reducing the total cost and dissolution of iron were found.     

Application of Taguchi method in the optimization of dissolution of ulexite in NH4Cl Solutions

The Taguchi method was used to determine optimum conditions for the dissolution of ulexite in NH₄Cl solutions. The ranges of experimental parameters were between 50–87 ‡C for reaction temperature, 0.05-0.20 gmL^-1 for solid-to-liquid ratio, 1–4 M for NH₄Cl concentration, 5–25 min for reaction time, and (-850+600)-(-90) Μm for particle size. The optimum conditions for these parameters were found to be 87 ‡C, 0.05 gmL^-1, 4M, (-300+212) Μm, and 18 minutes, respectively. Under these conditions, the dissolution percentage of ulexite in NH₄Cl solution was 98.37. Reaction products were found to be boric acid, ammonium tetraborates, sodium tetraborate decahydrate, calcium chloride, and sodium chloride.     

废弃葡萄籽中原花青素提取及测定研究

对原花青素的提取及测定进行了系统研究。考察了料液比、乙醇浓度、提取温度、提取时间等因素对原花青素提取的影响,并通过正交实验确立了最适合的提取条件为:料液比为1∶6、乙醇浓度为60%、提取温度50℃、提取时间60 min。极差分析表明提取温度对原花青素提取影响最大,其次是乙醇浓度、提取时间和料液比。铁盐催化比色法系统考察了反应时间、反应温度、反应介质的种类、酸的种类、酸的浓度、金属离子的种类及Fe3+的含量等因素对吸光度的影响,确立最适测定条件为:以正丁醇及5 mL的浓盐酸的混合液作为反应介质,浓度0.415 mol/L的Fe3+作为催化剂,60℃下反应60 min,测得的吸光度最大。     

银铟在复杂硫化锌精矿加压酸浸中的行为

实验研究了银铟在复杂硫化锌精矿加压酸浸过程中的行为,考察了浸出温度、浸出时间、硫酸浓度、氧压、精矿粒度及液固比对铟浸出率和银入渣率的影响,分析了铟在浸出初期的动力学. 结果表明,在浸出温度150℃、浸出时间90 min、硫酸浓度152 g/L、氧分压1.2 MPa、精矿粒度<45 mm及液固比5 mL/g的条件下,铟浸出率达76%以上,银入渣率达98%以上. In的初期浸出符合核收缩模型,受界面化学反应控制,表观活化能为70.67 kJ/mol.     

含铟氧化锌烟尘加压硫酸浸出工艺优化

对含铟氧化锌烟尘加压浸出进行正交实验及单因素实验,考察各因素对浸出的影响. 结果表明,各因素对铟浸出率的影响显著程度为初始硫酸浓度>液固比>压力>温度>时间,对锌浸出率为初始硫酸浓度>液固比>温度>时间>压力. 优化工艺条件为温度140℃,釜内压力0.6 MPa,时间90 min,液固比8 mL/g,初始硫酸浓度160 g/L,搅拌速率500 r/min. 该条件下锌和铟浸出率分别达99%和91%以上,锌与铟可同时高效浸出,浸出液残酸低,工艺稳定性好     

Dissolution kinetics of lead from a lead-oxide ore that consists mainly of cerussite by trichloroacetic acid and optimization of dissolution conditions

The dissolution kinetics of lead-bearing ore in trichloroacetic acid (TCA) solution were investigated. The effects of various parameters were studied to optimize the dissolution conditions and to determine the leach kinetics. An increase in leaching time, temperature, and TCA concentration, and a decrease in particle size enhanced the conversion rate. The results show that 99.26% of lead content was extracted from the samples with particle size range of –90 + 75 µm after 24 min leaching in 0.4 mol/L TCA at 800 rpm and 40°C. The following expression based on the Jander (three-dimensional) model can be described: [1–(1–x)^1/3]2 = 22.36 × 10^?3 (C_TCA)^1.1516(P)^0.55117(r)^0.92609exp (–20899/RT) t.     

Recovery of nickel from spent catalyst from palm oil hydrogenation process using acidic solutions

In this study, recovery of nickel from spent catalyst from palm oil hydrogenation process is carried out via extractive leaching process using sulfuric and hydrochloric acids. The effects of acid concentration, solid-liquid ratio, temperature and digestion time on the recovery (acid dissolution) process are investigated. It is found that sulfuric acid is the better leaching solution as compared to hydrochloric acid for recovery (dissolution) of nickel from the spent catalyst. Results from speciation modelling using VMINTEQ further imply that nickel can form sulfate complexes which are more stable than chloride complexes at concentrations higher than 1 M. The optimum conditions for maximum recovery at 85% are achieved at 67% sulfuric acid concentration, digestion time of 140 min, solid-to-liquid ratio of 1:14 and reaction temperature of 80 °C. At solution temperatures higher than 80 °C, the percentage nickel extraction is reduced. The optimization study presented here is useful for spent catalyst generators in the palm oil industry intending to recover valuable metals which may assist in reducing palm oil processing costs.     

铁闪锌矿浮选精矿生物浸出

研究了氧化亚铁硫杆菌浸出铁闪锌矿浮选精矿的过程, 考察了正无菌、原菌种与驯化菌等条件下铁闪锌矿的浸出效果和矿浆浓度对矿物中有价金属浸出速率的影响. 摇瓶试验表明: pH值2.0、温度35 ℃、细菌接种量10%、矿浆浓度5%、矿石粒度<35.5μm(90%以上)和摇床转速160r&#8226;min^-1浸出条件下, 经过驯化的氧化亚铁硫杆菌能够显著地提高铁闪锌矿的溶解速率和浸出率;提高矿浆浓度导致铁闪锌矿中有价金属浸出率降低, 但单位时间内总的锌离子浸出量相应提高.     

NaOH亚熔盐法分解钾长石矿

以高浓度NaOH溶液为亚熔盐介质分解钾长石矿精粉,考察了矿物粒径、NaOH溶液浓度、搅拌速度、反应时间、反应温度、液固比对K+溶出率的影响,并对分解过程动力学进行分析. 结果表明,100 mm粒径钾长石矿精粉的最佳反应条件为：NaOH初始浓度60%(w)、反应温度约160℃、搅拌速度400 r/min、液固质量比4:1、反应140 min,该条件下K+溶出率大于98%. 钾长石的分解符合粒径恒定的缩核模型,反应初期固相产物层内扩散为速控步骤. 80~140℃下,反应的表观活化能为110.42 kJ/mol.     

Kinetic Investigation of Reaction Between Colemanite Ore and Methanol

In the field of industry, it is very important that boron compounds are produced from boron ores. The aim of this study was to investigate the dissolution kinetics with carbon dioxide of colemanite in methanol medium in a pressure reactor and to derive an alternative process for producing boron compounds. Reaction temperature, stirring speed, solid/liquid ratio, pressure, and particle size were selected as parameters for the dissolution rate of colemanite. It was found that the dissolution rate increased with increase in pressure and reaction temperature, and with decrease in particle size and solid/liquid ratio. No effect of stirring speed was observed on conversion. The dissolution kinetics of colemanite were examined using both heterogeneous and homogeneous reaction models, and it was determined that the reaction rate can be described by a second-order pseudo-homogeneous reaction model. The activation energy was found to be 51.4 kJ/mol.     

Oxidative leaching kinetics of molybdenum-uranium ore in H2SO4 using H2O2 as an oxidizing agent

The processing of molybdenum-uranium ore in a sulfuric acid solution using hydrogen peroxide as an oxidant has been investigated. The leaching temperature, hydrogen peroxide concentration, sulfuric acid concentration, leaching time, particle size, liquid-to-solid ratio and agitation speed all have significant effects on the process. The optimum process operating parameters were: temperature: 95°C; H₂O₂ concentration: 0.5 M; sulfuric acid concentration: 2.5 M; time: 2 h; particle size: 74 μm, liquid-to-solid ratio: 14 ∶ 1 and agitation speed: 600 rpm. Under these experimental conditions, the extraction efficiency of molybdenum was about 98.4%, and the uranium extraction efficiency was about 98.7%. The leaching kinetics of molybdenum showed that the reaction rate of the leaching process is controlled by the chemical reaction at the particle surface. The leaching process follows the kinetic model 1 ? (1?X)^1/3 = kt with an apparent activation energy of 40.40 kJ/mole. The temperature, concentrations of H₂O₂ and H₂SO₄ and the mesh size are the main factors that influence the leaching rate. The reaction order in H₂SO₄ was 1.0012 and in H₂O₂ it was 1.2544.     

硫铝酸钙的氧化铝溶出性能

使用分析纯CaCO₃、Al₂O₃与CaSO₄·2H₂O配料,在1375℃、保温2 h的条件下合成了纯物相硫铝酸钙3CaO·3Al₂O₃·CaSO₄（C₄A₃S）,对其物相组成和微观形貌进行了表征。并探究了碳碱浓度、苛碱浓度、溶出温度、溶出时间、粒度等因素对C₄A₃S氧化铝溶出性能的影响。结果表明：C₄A₃S的氧化铝溶出性能随着碳碱与苛碱浓度的增加先提高,之后趋于稳定。粒度越小,溶出率越高。与七铝酸十二钙12CaO·7Al₂O₃（C₁₂A₇）相比,C₄A₃S的孔洞状结构使其氧化铝更易溶出,在10 min时氧化铝溶出率即达到98%以上,且溶出所需的碳碱浓度与溶出温度均低于C₁₂A₇。在最佳条件：碳碱80 g·L^-1、苛碱10 g·L^-1、溶出温度80℃、溶出时间10 min下,C₄A₃S的氧化铝溶出率为98.76%。     

Optimization of desulphurization of Artvin–Yusufeli lignite with acidic hydrogen peroxide solutions

In this study in which the Taguchi method was used, the optimization of sulphur removal by H₂O₂/H₂SO₄ solutions was carried out over lignite with higher content of sulphur from Artvin/Yusufeli, Turkey. In experiments, the ranges of experimental parameters were between 0.25 and 6.0 mol L⁻¹ for H₂O₂ concentration, 0.25–4 mol L⁻¹ for H₂SO₄ concentration, 10–60 °C for reaction temperature, 0.01–0.08 g mL⁻¹ for solid-to-liquid ratio, 15–120 min for reaction time, 200–300 rpm for stirring speed and 710–120 μm for particle size. The optimum conditions for these parameters have found to be 60 °C of temperature, 0.06 g mL⁻¹ of solid-to-liquid ratio, 60 min of reaction time, 250 rpm of stirring speed and −250 + 180 μm of particle size.A statistical experimental arrangement, L₂₅(5⁶) was prepared to determine optimum sulphur removal and ash removal ratios. The obtained yields were 97.85% in removal of total sulphur, 56.54% in removal of pyritic sulphur, 21.33% in removal of organic sulphur and 61.52% in removal of ash. According to variance analysis, it was seen that all parameters were effective in removal of pyritic and total sulphur, reaction temperature, solid-to-liquid ratio, reaction time, stirring speed, H₂O₂ and H₂SO₄ concentrations in removal of organic sulphur, and other parameters except acid concentration in removal of ash.