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81.
Nathália Vieceli Carlos A. Nogueira Manuel F. C. Pereira Fernando O. Durão Carlos Guimarães Fernanda Margarido 《Mineral Processing and Extractive Metallurgy Review》2017,38(1):62-72
The lithium extraction from a lepidolite concentrate using roasting, followed by water leaching, was studied. Several alternative additives were initially tested. The use of sodium and calcium sulfates as additives was evaluated in more detail. The influence of some process variables, namely the roasting time, roasting temperature and the additive/concentrate mass ratio, was studied applying a design of experiments. The lithium extraction was modelled and the fitted and validated model was used to optimize the process response. The increase in the additive/concentrate mass ratio, roasting time and temperature seems to result in solid state reactions and transformations that lead to phase, morphological and particle size distribution modifications, which were assessed by XRPD, SEM, and particle size analyses. In this process, lithium sodium sulfate formation constitutes a crucial step enabling the Li water leaching. High lithium extractions were estimated for several combinations of factors. At 850°C, lithium extractions over 90% are obtained when the roasting time is above 1.90 hour and the additive/concentrate mass ratios are over 0.77. An increase in the temperature to 875°C also leads to lithium extractions over 90% for a roasting time of 1 hour and an additive/concentrate mass ratio of 0.60. 相似文献
82.
G. Tiburcio Munive M.A. Encinas Romero A. Valenzuela Soto V. Vázquez Vázquez J. H. Coronado López 《Canadian Metallurgical Quarterly》2018,57(3):312-318
A novel process was used to extract manganese from minerals that are refractory to cyanidation and ammonium thiosulphate. These minerals, known as mangano-argentiferous compounds, are principally composed of manganese, silver, and iron and exhibit low recovery. The mineral of interest was obtained from the leaching tails procured in Monte del Favor, Hostotipaquillo, Jalisco, Mexico. The tailings were characterised by X-ray powder diffraction (XRD), atomic absorption, and energy dispersive X-ray spectroscopy (EDS) microanalysis. After mineralogical characterisation, the tailings were screened through a mesh (mesh number 100, 0.147?mm); later, they were subjected to a reductive leaching process, where the solid–liquid ratio was varied from 2:1 to 10:1. A 5:1 ratio yielded the highest manganese content. With sulphuric acid and sodium sulphite as the reducing agents, 96.05% of Mn could be extracted during the first 3?h, with a head grade of 3.58% and an acid consumption of 49.31?kg/t. The sulphite consumption was found to be 9.81?kg/t. 相似文献
83.
84.
Luis A. Cisternas Edelmira D. Gálvez 《Mineral Processing and Extractive Metallurgy Review》2018,39(1):18-33
This article reviews the use of seawater in mining with an emphasis on its use in Chile. The importance of the use of seawater in mining is highlighted in the introduction, then the main characteristics of seawater are reviewed, especially its potential effects on its use in mining. Subsequently, the consumption of seawater in Chile, especially in the regions located in the Atacama Desert, is analyzed based on statistics developed by Cochilco (Chilean Copper Commission). Later, the alternatives for the use of seawater and the distribution system are considered. The effect of seawater on the sulfide minerals flotation, the sulfide copper minerals leaching, and Caliche leaching is analyzed. We can conclude that the use of seawater has been increasing in Chile, which is already a reality, but there are challenges and opportunities that arise from the need to use seawater as a water resource. 相似文献
85.
A new method, the concentrated sulfuric acid acidolysis and water leaching (SAWL) of nickeliferous oxide ores, is proposed and the optimal conditions for recovery of nickel, cobalt and copper from a low-grade Chinese nickeliferous oxide ore are presented. A series of experiments were conducted which examined the effect of acid charge, acid curing temperature and acid curing time. Recoveries of up to 95%, 83% and 95% for Ni, Cu and Co, respectively were obtained with only the sulfuric acid at ambient temperature and atmospheric pressure. Comparing the percolation leaching with agitation leaching showed that percolation leaching was capable of extracting the valuable metals with water. The SAWL method was scaled to three-stages counter-current leaching tests using 1 kg of ore. The results indicate greater than 90% extraction for nickel and cobalt. 相似文献
86.
An extensive investigation of the influence of aliphatic alcohols on the metabolic activity of a heterogeneous culture has been carried out using flow microcalorimetry as a monitoring technique. The response of the culture to the addition of alcohols (n-C3 to n-C8, t-C4) has been examined for the microorganisms under endogenous conditions and substrate saturation conditions, and IC50 values were determined for each state. For the n-alcohols, the inhibitory behavior was further examined through systematic variations of substrate and alcohol concentrations; the results yield inhibition patterns which show specific behavior both as function of alcohol concentration and alcohol chain length. Generally, the toxicity results obtained with the heterogeneous culture follow rather closely those found in homogeneous cultures. However, the initial effect of alcohols at low concentration show marked variations among various types of culture or when compared to other reference systems. 相似文献
87.
Algal assays, using the marine diatom Nitzschia closterium, have established that humic acid (5 mg kg−1) can ameliorate the toxicity of the lipophilic complex Cu(oxine)2 (3 × 10−8 mol l−1 in unsupplemented seawater). The toxicity of Cu(PAN)2 is not ameliorated [PAN = 1-(2-pyridylazo)-2-napthol]. In conjunction with previous visible absorption spectrophotometry and polarographic measurements it was established that humic acid sequesters copper(II) from the hydrophobic complexes, releasing a ligand molecule. The copper(II) toxicity may be ameliorated provided the ligand itself is not toxic.Fulvic acid was significantly less effective in ameliorating toxicity. Because of the significant competition from Ca(II) and Mg(II) in seawater, it is inferred that humic substances may be more effective in ameliorating toxicity of hydrophobic copper complexes in fresh water. 相似文献
88.
The effect of sulfide on the formation of methane from acetate in granular sludge originating from a UASB reactor has been determined using a new batch anaerobic toxicity assay. The assay is based on measurement of the methane concentration in the closed head space of a serum bottle, thus allowing operation at constant pH and without loss of sulfide via off-gases.
Sulfide toxicity appeared to be correlated with the free hydrogen sulfide concentration in the pH range 6.4–7.2. However this correlation did not hold at pH = 7.8–8.0. Free hydrogen sulfide concentrations leading to 50% inhibition were 250 mgS l−1 in the pH range 6.4–7.2 and 90 mgS l−1 at pH = 7.8–8.0.
The high tolerance for sulfide toxicity exhibited by the granular sludge can probably be attributed to the existence of a pH gradient in the sludge granules leading to an increased internal pH. 相似文献
89.
通过渗滤法考察模拟酸雨对河道淤泥气泡混合土的侵蚀作用,试验过程中测定混合土试样的物理力学指标、渗滤液的pH值和Ca2+浓度值以及矿物组分受酸雨渗滤影响后的变化规律,研究考察酸雨对混合土性质的影响。试验结果表明：酸雨导致河道淤泥气泡混合土中的矿物水解并以Ca2+离子形式析出,导致混合土中性化。酸雨的酸性越强,土体中性化程度越高,在中性化过程中又有新的矿物生成,使混合土中矿物相对含量发生改变,导致混合土物理力学性质的变化;与正常雨水作用相比,经酸雨作用后的河道淤泥气泡混合土含水率和密度升高,强度降低,破坏模式向脆性化发展,并且酸雨的酸性越强,物理力学性质的变化越明显。 相似文献
90.
每年因铜冶炼会产生非常多的脱硒渣浮选尾矿,其中含铅量很高,铅是有毒性金属,若直接作为废渣处理不仅污染环境也是对资源的一种浪费。本研究以云南某企业的脱硒渣浮选尾矿为原料,利用湿法冶金的原理进行浸出实验,使矿料中的铅得到合理的回收利用。研究了在矿浆中加入不同浓度的NaOH、以及改变实验温度、固液比和反应时间等因素对铅浸出效果的影响;同时探究了C还原预处理对铅浸出效果的影响。实验结果表明：通过C还原预处理之后的矿料的铅浸出率有明显的提高,碳还原预处理时的最佳条件为：焙烧温度550℃、焙烧时间6h、碳粉与物料的比例为5:100;浸出实验的最佳条件为：浸出温度为90℃、固液比为1:10、NaOH浓度为180g/L、反应时间为1h。在此条件下矿料的浸出效果最好,最高浸出率为95.8%。 相似文献