The effects of mineralogy on the biological leaching of nickel laterite ores

The amenability of limonite ore, the iron rich nickel laterite phase, was observed to be less than saprolite, the silicate rich phase, when subjected to biological leaching with heterotrophic microorganisms. To understand this difference, controlled leaching of the various nickel laterite minerals was conducted using citric acid to mimic the chemical action of the organisms and subsequent characterisation of the leached residues. The raw ore and the leached mineral residues were examined using high-resolution synchrotron based X-ray diffraction and optical microscopy. The possible contribution of electrosorption and solid porosity was also considered. The results suggest that although electrosorption contributes to nickel and cobalt losses, it is the structural changes induced by the acid in the minerals which effects the recovery of the metals. Citric acid was found to dehydroxylate saprolite minerals resulting in an unstable nickel oxide and thus making it susceptible to acid attack. This behaviour was not observed in the limonite ore, which was found to be poorly leached by citric acid.     

黏土型钒矿分级富集浸出试验的研究

将黏土型钒矿进行分级富集,对直接分级得到的精矿及未经分级富集的原矿进行了对比浸出试验研究,考察了硫酸用量、助浸剂A及B对V2 O5浸出率的影响．结果表明,精矿较原矿难浸出,需适当增加硫酸、助浸剂A及B的用量以达到理想的浸出率;浸出1 t的V2 O5所用的硫酸量,精矿的用量比原矿的约节省1／5．     

无氰工艺回收利用黄金尾矿试验研究

为了综合回收利用内蒙古某黄金矿山堆浸尾矿中的金、银,采用无氰浸出工艺,选用新型无氰环保药剂作浸出剂,在矿浆质量浓度33%、pH=11、浸出剂用量2.0 kg/t、浸出时间24 h的条件下,金浸出率达52%,银浸出率约59%,浸出指标稳定。该工艺简单易行,可实现尾矿资源的二次利用,并能取得较大的经济效益。     

某矿床铀矿石浸出工艺参数的选择

分析江西某矿床铀矿石的组成和铀矿物形式,并通过试验研究确定处理该铀矿石的工艺流程和工艺参数.     

铀矿堆浸工艺中助渗剂应用的研究

在某些铀矿堆浸工艺中,由于矿石的泥化、膨胀和细颗粒迁移等原因,经常出现通道堵塞、渗透率低的问题,为此,提出了添加助渗剂的方案。助渗剂以表面活性剂为主体,目的是提高溶浸剂的渗透性和浸出工艺的效率。经对多种硬岩矿和泥矿的试验,证明其效果明显。还对助渗剂的作用机理作了初步探讨。     

The mechanism of leaching of gold from refractory ores

Refractory gold ores commonly contain free gold, submicroscopic gold, base metal sulphides, pyrite, pyrrhorite, labile sulphides and carbonaceous material. The analysis of gold deportment with the diagnostic leaching technique has opened a research field to gain more insight into the fundamentals of the kinetic behaviour of gold dissolution from refractory ores. Hence, more detailed studies on the kinetics of the reactions that occur during leaching with cyanide are now possible.Previous research work has indicated that the dissolution rate of gold during cyanidation becomes depressed after a certain time with no further increase in the rate. However, a second noticeable increase in the gold dissolution rate has been observed after a leaching time of 5 to 12 hours during some of the cyanidations, following the destruction of a mineral with the diagnostic leaching technique. If such a second increase in dissolution rate does not occur, the re-leaching of the filtered solids with a fresh cyanide solution yields an additional gold extraction of 4 to 8 %.Various experimental results have indicated that a passivative film forms on the surface of some of the liberated gold. The selective destruction of the various minerals with oxidative acid leaches destroys and/or decomposes certain minerals which may form films on the gold surface by precipitation. The chemical composition of these films and precipitates depends on the mineralogy of the sample. These films may be oxides, sulphides, carbonates and cyanide complexes.The complexes can be destroyed, depending on the nature of the film, by interstage dilute acid and/or cyanide washes in an agitated vessel. The destruction of the films exposes the gold surface for cyanidation. Whereas most of the previous studies on the leaching of gold have focused on the whole ore, the emphasis in this study was on the leaching behaviour of gold from various ore constituents. This approach of studying the leaching behaviour of different gold bearing minerals has provided reasons why some ores leach better than others.     

山东某风化壳型金矿氰化浸出试验研究

针对山东某风化壳型金矿进行了氰化浸出试验研究,考察了磨矿细度、氰化钠用量、石灰用量、液固比、搅拌时间等对金浸出效果的影响规律。试验结果表明,较粗的磨矿细度和较低的矿浆浓度对浸出更有利,在最佳的试验条件下,该矿石的金浸出率可达到95.87%,炭吸附率可达到99.58%。     

Agglomeration and column leaching behaviour of goethitic and saprolitic nickel laterite ores

Processability of complex, low-grade nickel (Ni) laterite ores via heap leaching is very limited due to some intractable geotechnical and hydrological challenges such as poor heap porosity/permeability and structural stability. This work presents some investigations on laboratory batch drum agglomeration and continuous column leaching behaviour of saprolitic (SAP) and goethitic (G) Ni laterite ores as part of the quest for an effective ore pre-treatment process for enhanced heap leaching. As a focus, the effect of ore mineralogy/chemistry on the agglomeration and column leaching behaviour of −2 mm (crushed from −15 mm run-of-mine) G and SAP Ni laterite ores was examined. To produce ∼5–40 mm agglomerates in <15 min, the SAP ore required a higher H₂SO₄ (30 wt.%) binder dosage compared with the G ore, although both ores displayed substantially similar, coalescence-controlled agglomeration mechanism. The resulting G agglomerates were more robust than the SAP ones based upon their compressive strength and acidic solution soak test measurements. However, over 100 days of continuous column leaching, the structural stability of the SAP agglomerate bed was slightly greater than that of G agglomerates, reflecting a lesser slump of the former. The pregnant leach solution analysis revealed greater Ni/Co extraction rates from the SAP than the G agglomerates. Whilst the total mass of acid consumed per ton dry ore processed was greater for the SAP ore, the total kg acid per kg Ni extracted was markedly lower. Incongruent leaching of gangue minerals’ constituent elements (e.g., Fe, Mn, Mg, Al and Si) occurred and contributed significantly to the overall acid consumption. The findings show the relevance of agglomeration and column leaching tests for providing useful information for plant designing and optimization of Ni laterite heap leaching operations.     

铜矿峪低品位矿石地下生物溶浸可行性研究

本文详细阐述了利用生物浸出技术回收铜矿峪矿崩落区、毛石台及5#E矿体上部存留的大量低品位氧化矿及表外矿的可行性。     

某砂岩铀矿床不同岩性铀矿石浸出性能研究

某矿床发育有砂岩和泥质砂岩2种类型铀矿体,铀资源主要存在于泥质砂岩型铀矿体中。工艺矿物学和室内酸法搅拌浸出试验结果表明:原矿铀品位与黏土矿物含量呈正比,以蒙脱石为主的黏土矿物既是铀富集的重要吸附剂,也是导致矿石渗透性较低的主要因素;在液固体积质量比为5L/kg,硫酸质量浓度≥5g/L条件下,砂岩铀矿石和泥质砂岩铀矿石的浸出性能均较好,其四价铀和六价铀均能达到较好的浸出效果,总铀浸出率均可达75%以上。     

Interactions between sulphides and manganese dioxide in thiosulphate leaching of gold ores

The interactions between manganese dioxide and pyrite or chalcopyrite were investigated in both the ammoniacal and ammoniacal thiosulphate leaching systems. Pyrite and chalcopyrite dissolved at enhanced rates in the presence of manganese dioxide in both ammoniacal and ammoniacal thiosulphate solutions. The interactions between manganese dioxide and sulphides were also applied in the thiosulphate leaching of gold from a pyrite concentrate and a sulphide ore. The addition of a small amount of manganese dioxide in the thiosulphate leaching of the sulphide bearing gold ores improved both the kinetics and the overall gold extractions without much impact on thiosulphate consumption.A pre-treatment process with copper ammoniacal solutions enhanced gold extractions from the sulphide bearing ores and reduced thiosulphate consumption to a large extent. The sulphides partially degraded in the pre-treatment process likely exposing gold to leach solutions. SEM images of the surface corrosion of pyrite and chalcopyrite in contact with manganese dioxide showed that the pre-treatment with manganese dioxide enhanced the degradation of the sulphide matrices, thus achieved a better gold leaching from the sulphide bearing ores.     

金川低品位氧化镍矿的酸法制粒堆浸工艺研究

对于金川有色金属公司低品位的氧化镍矿,目前的火法和湿法冶金工艺,生产成本高,难以回收利用。通过制粒预处理,加入润湿液与矿石中的耗酸组分作用,可以预先破坏碳酸盐和Ca、Mg的氧化物,降低硫酸浸出过程中CO2气体逸出对颗粒的损害。选择N603作为低品位氧化镍矿的黏合剂,有效地改善了堆浸的渗透性,浸出过程中,矿石颗粒未发现严重的破裂和泥化现象。预处理后矿石浸出,每t矿石总用酸量258.8kg,镍浸出率85%以上。如果利用该公司硫酸厂大量的低浓度硫酸来堆浸,则在经济上和环境保护方面都比较合理。     

以风化煤为底物制取生物甲烷的潜力分析

我国拥有丰富的风化煤储量,因其高度被氧化的独特性质,可应用的领域极为有限,目前主要被作为改善土壤性质的肥料和制取腐殖酸的来源。以风化煤为底物制取生物甲烷是一种具有探索性的全新生物发酵工艺,探究其可行性及模拟实验过程中风化煤的物性特征变化有利于拓宽风化煤的资源利用和环境改善,并可以进一步丰富煤生物产气理论。实验选取内蒙古乌海和山西晋城两地不同风化程度煤样,以煤层矿井水为菌种来源,在适宜环境条件下开展模拟产气实验,通过生物产气模拟和红外光谱测试,分析不同风化程度煤的生物产气能力及其内在因素,以揭示其产气潜力及物性变化特征。结果表明:①随着煤的风化程度加深,可燃基CH 4产气量明显增加,两组煤样中可燃基CH 4生成量最高分别达到7.13,4.20 mL/g;②不同风化程度的煤样均出现了产气高峰,时间基本都出现在15~30 d,各组中随着煤样风化程度不断加深,产气高峰出现时间也越来越早;③随着煤的风化程度加深,煤中芳环被不断打开,大分子结构被破坏,同时煤中羟基、氨基等基团含量趋于降低,脂碳结构逐渐解体,含氧官能团成为主要结构,氧含量比例不断增高,更容易被微生物降解;④菌群鉴定表明风化煤不仅含有大量产生生物气所需的第1阶段和第2阶段细菌,更含有甲烷杆菌属、甲烷球菌属等多种类型的产甲烷菌群,具有把风化煤转化为生物甲烷的环境条件。实验结果最终反映了风化煤具有转化为生物甲烷的潜力,并有利于提高我国风化煤的资源利用率。     

响应曲面法优化氨浸低品位氧化铜的研究

探究在用氨水作为浸出剂的条件下浸取云南某碳酸盐型低品位氧化铜矿中铜工艺条件。采用响应曲面法对影响铜浸出率的3个主要影响因素,即氨水浓度、液固比和浸出时间进行优化。试验结果表明:在常温常压条件下,浸铜最佳工艺条件为氨水浓度2.23 mol/L,液固比为2.46∶1,浸出时间为2.99 h,其浸出率达到77.83%,实测结果与响应曲面拟合所得方程的预测值符合良好。     

Leaching of low grade limonite and nontronite ores by fungi metabolic acids

This study was designed to investigate the nature of nickel and cobalt dissolution from limonite and nontronite ores. Leaching was achieved using 0.2–3 M of citric, lactic and malic acids. The effect of acid type, acid activity, oxygen reduction potential and pulp density on metal dissolution was studied systematically. The effect of leaching on the mineralogy of the ore was investigated by optical microscopy and by synchrotron based X-ray diffraction. From the experiments, it was shown that nickel and cobalt dissolution were dependent on acid activity, oxygen reduction potential, pulp density and mineralogy. The extent of metal dissolution was less affected by the type of acids. The trend of selectivity in limonite and nontronite are Co > Mn > Mg. Metal selectivity was intimately associated with the host minerals containing nickel and cobalt.