Leaching chalcopyrite with sodium chlorate in hydrochloric acid solution

Investigation of thermodynamic and kinetic regularities of asbestos waste leaching processes

Cobalt and molybdenum are valuable metals whose presence in nature is very limited. The consumed catalyst, which is abundantly available in the petroleum refinery industry, is a potential source of those metals. A hydrometallurgical process using acid as a leaching agent is usually used to extract and separate the metals more effectively. This method is considered capable of yielding recovery of a higher percentage of metal. In this study, hydrochloric acid solutions at various concentrations of 1.0, 1.5 and 2 M were used. The consumed catalyst was obtained from Pertamina Refinery Unit IV, Cilacap, Indonesia. Leaching experiment was carried out for 300 minutes and sampling was undertaken at 1, 3, 5, 15, 30, 90 and 300 minutes. The particle size and agitation speed were fixed at 200 mesh and 400 rpm. Samples of consumed catalyst were analyzed using EDXRF before the leaching process. Samples of solution were analyzed using ICP-EOS. Experimental results have shown that the recovery of cobalt and molybdenum increases with the increase of either concentration of hydrochloric acid or temperature. The highest recoveries in cobalt and molybdenum were 34.66% and 5.03%, respectively, obtained at a concentration of hydrochloric acid of 2 M and temperature 60°C.

Mechanism and leaching kinetics of silver recovery from zinc leaching residues by ultrasonic synergism with sodium chlorate

Determination of solubility of ZnCl2 in hydrochloric acid solutions for 68Ga production in liquid target

Objective. To investigate the pressure in the proximal duodenum after intraduodenal injection of 0.1 M hydrochloric acid and sunflower oil solution in patients with chronic biliary pancreatitis and postcholecystectomy syndrome depending on the state of excitation and inhibition in the pancreas. Materials and methods. We examined 316 patients with a clinical diagnosis of chronic biliary pancreatitis and 53 patients with postcholecystectomy syndrome. The pancreatic function was assessed by the method of complex fractional gastroduodenal probing. To assess the state of excitation and inhibition processes in the pancreas, the pressure in the antrum of the stomach was measured during stimulated pancreatic secretion using an open catheter. Results. In patients with chronic biliary pancreatitis and postcholecystectomy syndrome after intraduodenal administration of 0.1 M hydrochloric acid solution and sunflower oil, 4 pressure ranges in the duodenal cavity were observed: 0 – 5, 6 – 13, 14 – 18 and 19 – 42 mm Hg. After intraduodenal injection of 0.1 M hydrochloric acid solution among patients with chronic biliary pancreatitis at a pressure in the antrum of the stomach of 0 – 5 mm Hg. statistically significantly increased the proportion of patients with a pressure of 6 – 13 mm Hg (48.09%) and decreased the proportion of patients with a pressure of 19 – 42 mm Hg. (19.85%) in the duodenal cavity compared to the corresponding figures for unstable pressure in the antrum – 35.59 and 30.51% (p < 0.05) and for pressure in the antrum of the stomach 6 – 9 mm Hg – 32 and 36% (p < 0.025). Among patients with postcholecystectomy syndrome with a pressure in the antrum of the stomach of 0 – 5 mm Hg, the proportion of patients with a pressure of 6 – 13 mm Hg increased statistically significantly (52.94%) and the proportion of patients with a pressure of 19 – 42 mm Hg (11.76%) decreased compared with the corresponding figures for unstable pressure in the antrum – 19.35 and 51.61% (p < 0.01). After intraduodenal administration of sunflower oil among patients with chronic biliary pancreatitis with a pressure in the antrum of the stomach of 0 – 5 mm Hg, the proportion of patients with a pressure of 14 – 18 mm Hg increased statistically significantly (47.33%) and decreased the proportion of patients with a pressure of 19 – 42 mm Hg (40.46%) compared with the corresponding figures for unstable pressure in the antrum – 32.2 and 64.41% (p < 0.01), 6 – 9 mm Hg – 36 and 64% (p < 0.01) and 10 and above mm Hg – 17.65 and 82.35% (p < 0.025). Conclusions. The pressure in the proximal duodenum after administration of 0.1 M hydrochloric acid solution and sunflower oil depends on the state of the excitation process in the pancreas: the pressure in the range of 0 – 5 and 6 – 13 mm Hg after administration of 0.1 M hydrochloric acid solution and 6 – 13 and 14 – 18 mm Hg after administration of sunflower oil indicates normal or reduced pancreatic excitability, pressure in the range of 14 – 18 and 19 – 42 mm Hg after administration of 0.1 M hydrochloric acid solution and 19 – 42 mm Hg after administration of sunflower oil – increased pancreatic excitability.

Microgram amounts of iron(III), gallium(III), thallium(III), antimony(V), and antimony(III) were collected by adsorption on activated carbon from hydrochloric acid solutions. The extent of adsorption was determined radiochemically or spectrophotometrically. The hydrochloric acid concentrations that gave the highest recoveries (_??_90%) were: 7M for gallium, 1M for thallium(III), 9M for antimony(V), and 3M for antimony(III). Thallium(I) was not adsorbed, but it was oxidized to thallium(III) by air in the presence of activated carbon. Iron(III) was adsorbed more satisfactorily from 0.1M hydrochloric acid-(6-12)M lithium chloride solutions than 6-10M hydrochloric acid solutions. Probably the metals are adsorbed as chloro-complexes. Iron and gallium in aluminum alloys were determined spectrophotometrically after adsorptive separation.

Calcium ion selectivity and isotope effects studied by using benzo-18-crown-6 resins

The partitions of uranium (vi) and thorium between hydrochloric acid solutions and solutions of tri‐n‐butyl phosphate (TBP) in benzene or kerosene have been investigated at different concentrations of hydrochloric acid and solvent, and at different temperatures. An infra‐red spectral study has also been made of the organic solutions obtained in the extraction of uranium. The effect of organic solvent on the extractions has also been examined.

Red mud as the main byproduct generated during alumina extraction from bauxite. Owing to the high iron content in the red mud and the high correlation between iron and scandium during the leaching process, it is necessary to extract the iron from the red mud and to further enrich the scandium in advance for the acid leaching extraction of scandium. In this research, the theory of red mud segregation roasting ore phase reconstruction is proposed, so that the iron and scandium in the red mud undergo a corresponding transformation, thereby achieving iron recovery in magnetic separation concentrate by magnetic separation, and enrichment of scandium in magnetic separation tailings. On this basis, the effects of temperature, leaching time, solid to liquid ratio and hydrochloric acid concentration on the leaching of scandium in magnetic separation tailings were studied optimal leaching process conditions and determine the leaching kinetics. A maximum Sc leaching efficiency of 83.94% was obtained at optimum leaching conditions of 200 rpm agitation speed, hydrochloric acid solution 20%, 80°C for 3 h, and solid/liquid ratios 1:10 (g/mL), −74 µm sample particle size. The process of leaching scandium with magnetic separation tailings conforms to the kinetic characteristics of multiphase liquid-solid region reaction, the apparent activation energy of scandium is 26.77 kJ/mol, and the leaching efficiency of scandium is controlled by the chemical reaction step.

One-step leaching mechanism for total elemental recovery from spent lithium-ion batteries utilizing ethylene diamine tetraacetic acid

Investigation into the effect of mechanical activation on the leaching of chalcopyrite in a glycine medium

In this research, we extracted silicon and iron oxides from the waste ash of the Mongolian fourth thermal power plant by a precipitation method. The samples were analyzed using XRD, XRF, BET, and SEM, and the following conclusions were reached. From the quantitative analysis of the chemical composition, the bottom and fly ash of the Mongolian fourth thermal power plant belong to the acid ash. The results of instrumental analysis of iron oxide obtained from the waste ash (XRF, XRD, BET, SEM), the ratio of ash to hydrochloric acid is 1:6, the hydrochloric acid concentration is 20%, the reaction temperature is 75°C, stirring speed is 250 rpm. The properties of the prepared iron oxide are the best and yield 20%, purity of 41.587%, average pore diameter of 7.5379 nm, and specific surface area of 38.87 m2 /g.The results of instrumental analysis of silicon dioxide obtained from the waste ash (XRF, XRD, BET, SEM) show the ratio of ash to hydrochloric acid is 1:6, the hydrochloric acid concentration is 20%, the reaction temperature is 75°C, stirring speed is 200 rpm. The yield is about 75%, the purity is 99.999%, the average pore diameter is 27.96 nm, and the specific surface area is 353.59 m2 /g.

Recovery of palladium(II) and gold(III) from diluted liquors using the resin duolite GT-73

Although ammonia leaching of copper from slags has been reported generally as a part of copper slag utilization methods, but no detailed studies have been reported in the literature. In this research, we tried to investigate the effect of different parameters on ammonia leaching of copper from copper smelting slag by identifying different copper-bearing phases and following them during leaching time. Mineralogical characterization of the smelting slag (1.7 pct Cu) was done using X-ray fluorescence, X-ray diffraction, optical microscopy, diagnostic leaching tests, and scanning electron microscopy. The characterization studies indicated that main copper-bearing species are soluble copper oxides and chalcocite along with minor amount of covellite, bornite, blister copper particles, and chalcopyrite. It was also found that only approximately 0.2 pct Cu was present in the insoluble bulk silicate phases. These results suggest that approximately 88 pct of the total copper of slag could be extracted by ammonia sulfide leaching. Leaching tests were carried out and the effects of various parameters, namely pH, ammonia concentration, temperature, presence of oxygen, stirring speed, and pulp density were examined on copper leaching. The temperature and stirring speed had the most pronounced effect on the copper leaching, whereas ammonia affected the leaching yield at low concentrations of ammonia. It was found that 78 pct of Cu could be extracted within 4 hours and under optimum conditions: T = 343 K (70 °C), 2M ammonia, pH 10.5, stirring speed = 900 rpm, pulp density = 10 pct (ws/v). The kinetic data were analyzed with the shrinking core models, and it was found that the leaching process is controlled by both the interfacial transfer and diffusion across the product layer and the activation energy is calculated to be 49.4 kJ mol−1.

Chalcopyrite leaching rate in atmospheric pressure and in sulfate media with ferric ion is low because of passive layer formation around chalcopyrite particles. In this investigation pyrite is used as a catalyst of chalcopyrite leaching. Because of galvanic interaction between chalcopyrite and pyrite, the chalcopyrite leaching rate is increased. Effects of parameters such as stirring speed, pyrite to chalcopyrite ratio, solution potential, temperature, and initial acid concentration were investigated. Results showed that maximum copper recovery (more than 95%) is obtained in less than 24 h, stirring speed of 1150 rpm, pyrite to chalcopyrite ratio 4, solution potential 410 mV, temperature 85 °C, and initial sulfuric acid concentration 45 g/L. Also, kinetic investigation showed that chalcopyrite dissolution in the presence of pyrite followed the shrinking core model and the reaction was controlled by the surface reaction. Activation energy (Ea) was calculated at 77.79 kJ/mol. Surface studies showed that in the absence of pyrite, the surface of chalcopyrite particles was covered by passive layer.