Nb and Ta-ore minerals are exclusively oxide minerals, such as columbite-tantalite. • State of the art of Nb and Ta extraction from columbite and tantalite ore minerals. • Discussion of commonly used processes from leaching to extraction of Nb and Ta. • Novel ammonium fluoride process as an alternative to HF leaching.

Silver minerals are known to have slow leaching rates and low overall extraction and require a high concentration of cyanide and a long retention time to maximize leach extraction. Their response to cyanidation is considered mild to moderately refractory, largely due to complex mineralogical compositions. New research on …

Nowadays, due to fast global industrial progress and near diminution of high-grade ore reserves, there has been massive call to cost-effectively process the resources of low-grade ores and industrial effluents for metal extraction. However, conventional approaches cannot be used to process such resources due to high capital cost and …

Sulfuric acid solution containing ferric iron is the extractant for industrial heap bioleaching of copper sulfides. To start a heap bioleaching plant, sulfuric acid is usually added to the irrigation solution to maintain adequate acidity (pH 1.0–2.0) for copper dissolution. An industrial practice of heap bioleaching of secondary copper sulfide ore …

Cyanide is the most widely used substance for gold extraction due to its relatively low cost, effectiveness in dissolving gold and silver, and selectivity for these metals. Dissolution of gold and silver requires oxidation [2,3,4], most commonly in cyanide leaching. The cyanidation process under normal conditions involves two electrochemical ...

This type of gold ore is suitable for TU/ETU leaching. The highest Fe-bearing gold ore was the most difficult to extract Au in ETU/TU leaching. There are at least two detrimental factors in TU leaching of Fe-rich ... Electrochemical behavior of gold dissolution with a novel eco-friendly synthetic gold lixiviant. Minerals Engineering, Volume 191 ...

The current study focuses on alkali-assisted roasting, dissolution, and recovery of mixed oxides of niobium (Nb) and tantalum (Ta) from a ferro-columbite concentrate collected from Jos Plateau in Nigeria. Alkali-assisted roasting and water-based leaching to extract Nb and Ta using guanidine carbonate salt were adopted for …

Iridium is widely used in high-temperature corrosion protection, catalytic oxidation, and electroluminescence owing to its excellent catalytic activity, corrosion, and oxidation resistance at high temperatures. Considering the high value of iridium-containing secondary resources, scarcity of iridium, and low recovery yield, it is important to …

How? There are two plausible explanations. First, most of the copper extracted from ROM ore originates from the leaching of the fines. Second, large ore particles tend to fracture and break over time, thus exposing fresh mineral grains to the …

Potassium and phosphate were extracted at low temperature by acid hydrolysis process to decompose a new type of associated phosphorus and potassium ore. The main factors affecting the dissolution rate were investigated, such as grinding fineness, the amount of sulfuric acid and fluoride salt, reaction time and temperature, etc. …

Under optimal conditions, the extraction percentage of zinc was 99.22% and dissolution of silica was as low as 0.56%. XRD examination of the samples demonstrated that all the zinc-bearing minerals were transformed into ZnSO 4 ·H 2 O while combined silica and iron were changed to quartz and rhomboclase (FeH (SO 4 ) 2 ·H 2 O) after acid …

extraction, dissolution, and functional materials of chitin: research progress and prospects Jiake Wang, Changchang Teng and Lifeng Yan * As a recyclable and inexhaustible renewable resource, chitin is one of the most abundant polysaccharides in nature. It has excellent biocompatibility, biodegradability, and non-toxicity and has been widely ...

For instance the nickel dissolution rate increased from 8.1 to 26.4% upon the application of pretreatment of a nickel laterite sample . With increasing microwave power and preheating time Ni-laterite ore, Ni extraction has been also increased about 80% .

In this study, the extraction of different metals from bauxite ore was investigated with a two-stage leaching process. At the first stage of leaching, the conditions of the selective removal of iron from bauxite and dissolution of titanium in the ore were identified in the presence of oxalic acid under atmospheric conditions.

Complete dissolution is critical for the accurate determination of the elemental and isotopic compositions. Sample digestions must be very effective and completed in the shortest time with minimal contamination, low reagent consumption, …

In a study by Stuurman et al. [11], sulphuric acid in the presence of hydrogen peroxide as a reducing agent was able to extract about 95% copper and 80% cobalt from a copper-cobalt oxide ore ...

Chalcopyrite (CuFeS2) is commonly used ore in production of copper, but leaching of this ore is very slow and inefficient due to "passivation" during leaching at atmospheric conditions. ... 30, 59] can be used to increase the dissolution kinetic and copper extraction recovery by eliminating the effect of this passivation layer forms, …

The oxidation of sulfide-based ores is industrially relevant as it facilitates the extraction of valuable metals and eliminates undesired elements from an ore. Even though oxidation can be done thermally (pyrometallurgy), solution-based (hydrometallurgical) methods are currently sought as they represent a more sustainable option. Here, the …

In the present case, the dissolution behaviour of copper and cobalt from Cu–Co oxidized ore using synthetic organic acids (independent of microorganisms) was studied. The effect of leaching

Thus, for successful extractions, the impurity content in the oxide mineral ore and choice of extraction method and/or extraction agents are key [11]. ... dissolution and extraction techniques suitable for complex Nb-Ta mineral ore matrices or concentrates largely depend on certain factors. Apart from the physicochemical properties, such as ...

Solvent extraction (SX)Solvent extraction of zinc (Zn)Zinc can be used to recover high-purity Zn from sulphide mineral leaching solutions, low-grade ores, and secondary resourcesSecondary resources. ... After the dissolution of the ore/waste into an aqueous medium (i.e., leaching), the metal to be recovered can be separated and …

Due to the high sulfuric concentration during dissolution, a local saturation zone close to the dissolution front caused the precipitation of iron oxyhydroxides. The calcium-rich sample shows lower REE extraction by leaching (63% maximum) mainly due to the entrapment of REE-bearing minerals by a gypsum layer, and lanthanide's uptake …

The results indicated that the temperature, acid concentration, and liquid–solid ratio were positively correlated with nickel extraction. Additionally, the dissolution process of goethite from a microscopic perspective was observed and confirmed, that the dissolution of goethite and the hydrolysis to produce hematite occurred simultaneously.

The overall process of dissolution, solvent extraction and electrowinning is known as SX-EW. Fig. 3 shows a typical flow diagram of LX/SX/EW. Figure 3. ... The dissolution of mineral ore takes place through the following stages: (1) diffusion of reactant through the diffusion layer, (2) adsorption of the reactant on the solid, (3) chemical ...

Weeklong leaching experiments with 0.5 M H 2 SO 4 revealed a higher copper extraction rate (≥73%) from coarse ore particles (5.6–11.2 mm). Along with the copper extraction, iron (29.6 wt%), aluminum (70.2 wt%), magnesium (85.4 wt%), and calcium (44.4 wt%) were also leached out considerably through the dissolution of …

Biomining is a well-established global biotechnology which uses aerobic, acidophilic microorganisms to catalyze the oxidative dissolution of sulfide minerals present in ores, concentrates, and mining wastes. Mineral bioprocessing at commercial scale is currently restricted to sulfide ores where the target metal is either surrounded by sulfide ...

This assumption was supported by observing 72% extraction of gold from ore into the solution in the CIL-1 test, while longer retention time (36 h) enhanced the dissolution of gold to 83% (CIL-2). Fleming et al. (2011) also demonstrated that in a CIP plant, all the leachable gold is already present in solution before the first carbon …

Results of dissolution studies showed that the copper oxide ore leaching in H 2 SO 4 solution increase with increasing time, pH, stirring speed and temperature at fixed H 2 SO 4 concentration of 0 ...

Then their further analysis showed that temperature and reaction time are the main factors affecting the dissolution of lithium minerals ... Taking global warming potential as an example, the intensity of lithium extraction from ore is 15.69 tCO 2eq /t, 47.7 times that from brine (0.33 tCO 2eq /t) (Jiang SY et al., 2020).

In contrast, the Ga extraction and Fe dissolution have an obvious decline. Especially, the dissolution efficiency of Fe is only 2.1% at 2 h, indicating the hydrolysis of Fe 3+ has completed at this juncture. Therefore, the optimal leaching time is determined to be 2 h. ... The raw ore, as well as the activated product and leach residue obtained ...