稀硫酸浸出处理铅阳极泥

采用焙炒氧化—稀硫酸浸出处理铅阳极泥,技术可行,流程合理,银、铜的直收率均在98％以上。

Enrichment of ferric iron on mineral surface during bioleaching of chalcopyrite

In order to investigate the enrichment of ferric iron bound by extracellular polymeric substance （EPS） on the mineral surface during bioleaching of chalcopyrite, several methods including sonication, heating and vortexing were used and sonication at 48℃ was shown as a good way to extract ferric iron. Scanning electron microscope （SEM） and energy dispersive X-ray spectrometer （EDX） analysis showed that lots of cracks and pits can be found on the chalcopyrite surface after bioleaching and that iron oxide was filled in these cracks and pits. The variations of contents of ferric iron and EPS on the chalcopyrite surface were investigated. The results indicated that the content of EPS increased rapidly in the first 10 d and then maintained at a stable level, while ferric iron content increased all the time, especially in the later stage of bioleaching.

Treatment of copper-rich gold ore by cyanide leaching, ammonia pretreatment and ammoniacal cyanide leaching

The treatment of a copper sulphide-bearing gold ore by direct cyanide leaching, ammonia pretreatment and ammoniacal cyanide leaching was investigated. Dissolution behaviour of gold and copper in these leaching systems was demonstrated. Severe interference by the copper containing sulphides with cyanide leaching of gold is observed at p（NaCN）〈5 g/L. This is consistent with speciation calculations. Ammonia pretreatment is shown to readily eliminate the copper interference, allowing almost complete extraction of gold with concomitantly low reagent consumption in subsequent cyanide leaching. In ammoniacal cyanide system, Box-Behnken experimental design shows the main and interaction effects of NH3, NaCN and Pb（NO3）2. The concentrations of NH3 and NaCN are statistically confirmed to be significant factors affecting extraction of gold while the effect of Pb（NO3）2 is limited. Increasing the concentration of NH3 improves the selectivity and extent of gold extraction and reduces the cyanide consumption. The contribution of reagent interactions to gold extraction is statistically insignificant. These findings highlight that ammonia pretreatment and ammonia-cyanide leaching are promising approaches for the treatment of gold ores with high copper sulphide content.

Pressure leaching of bismuth sulfide concentrate containing molybdenum and tungsten in alkaline solution

The leaching results of bismuth sulfide concentrate containing molybdenum and tungsten in air-H2O2-NaOH system, pressure-O2-Na2CO3 system and pressure-O2-NaOH system were investigated. The results show that the extraction of molybdenum, tungsten and sulfur goes up with the increase of NaOH concentration, oxygen partial pressure and reaction time. The extraction of molybdenum and tungsten also rises up with temperature, but the leaching ratio of sulfur increases initially to a peak of 98% at 150℃ and then decreases with the increase of temperature. Under the optimal conditions, the extraction of molybdenum, tungsten and sulfur is more than 95.6%, 93.8% and 96.0%, respectively, and the main phases of residue are Bi2O3 and Fe2O3. Therefore, the method of pressure leaching in alkaline solution is provided as an effective separation of molybdenum, tungsten and sulfur from bismuth and a beneficial pretreatment for consequent process.

Effect of mixed moderately thermophilic adaptation on leachability and mechanism of high arsenic gold concentrate in an airlift bioreactor

A refractory gold concentrate with 19% arsenic was treated by a mixed moderately thermophiles in an airlift bioreactor through an adaptation protocol. The moderately thermophiles could respond well to 20%(w/v) pulp density with less than 10% loss of productivity, and resist arsenic up to 15 g/L. There were a lot of jarosite, arsenolite and sulfur, but not scorodite and ferric arsenate in the bioleached residue. Jarosite passivation and lower sulfur-oxidizing activity of the cells due to the toxicity of the high concentrations of soluble arsenic and iron ions at low p H value should mainly response for the incomplete extraction at high pulp density. The initial bacterial community did not change in nature except for new found P aeruginosa ANSC, but sulfur-oxidizing microorganisms have been dominant microorganisms after a long time of adaptation. Pseudomonas aeruginosa originating from the gold concentrate should be closely relative to the metabolism of the organic matters contained in the refractory gold concentrate.

Combined treatment of landfill leachate with fecal supernatant in sequencing batch reactor

A laboratory-scale sequencing batch reactor (SBR) is used to treat landfill leachate containing high concentration of ammonium nitrogen with municipal fecal supernatant. The SBR system is operated in the following sequential phases: fill period, anoxic period, aeration period, settling period, decant and idle period. The results indicated that the average removal efficiencies of COD, BOD5, TN, NH 4+-N were 93.76%, 98.28%, 84.74% and 99.21%, respectively. The average sludge removal loading rates of COD, BOD5, TN and NH 4+-N were 0.24 kg/(kg SS?d), 0.08 kg/(kg SS?d), 0.04 kg/(kg SS?d) and 0.036 kg/(kg SS?d), respectively. Highly effective simultaneous nitrification and denitrification was achieved in the SBR system. The ratio of nitrification and denitrification was 99% and 84%, respectively. There was partial NO?2 denitrification in the system.

Microwave pretreatment for enhanced selective nitric acid pressure leaching of limonitic laterite

As clean energy,the microwave is commonly used to pretreat various ores.In this work,the microwave dielectric properties of limonitic laterite ore were measured by resonant cavity perturbation technique and the effects from microwave were systematically investigated.Results indicated that limonitic laterite had high microwave absorbance.After microwave pretreatment,the microstructure of the laterite became less aggregated and more porous and the main phase transformed from goethite to hematite that improved leaching in nitric acid(1.2 kg HNO3/kg ore);Ni,Co,Fe,and Mg extraction ratios were 95.2%,98.1%,1.8%and 15%,respectively,after leaching for 60 min at 200°C and 500 r/min.Furthermore,in the process of goethite to hematite by microwave pretreatment,the nickel-containing mineral is activated,which makes nickel be leached easily.The leaching process has high Ni extraction ratio compared to that without microwave(82%)and conventional pretreatment(90.4%).Therefore,microwave pretreatment of limonitic laterite before nitric acid pressure leaching is an effective way to improve the selectivity and extraction of the leach.

UV-Catalytic Treatment of Municipal Solid-Waste Landfill Leachate with Hydrogen Peroxide and Ozone Oxidation

The performance of UV/H_2O_2, UV/O_3, and UV/H_2O_2/O_3 oxidationsystems for the treatment of municipal solid-waste landfill leachatewas investigated. Main objective of the experiment was to removetotal organic carbon (TOC), non-biodegradable organic compounds(NBDOC) and color. In UV/H_2O_2 oxidation experiment, with theincrease of H_2O_2 dosage, removal efficiencies of TOC and coloralong with the ratio of biochemical oxygen demand (BOD) to chemicaloxygen demand (COD) of the effluent were increased and a betterperformance was obtained than the system H_2O_2 alone.

Well-controlled stirring tank leaching to improve bio-oxidation efficiency of a high sulfur refractory gold concentrate

For the high sulfur refractory gold concentrate with 41.82%sulfur and 15.12 g/t gold,of which 82.11%was wrapped in sulfide,a well-controlled stirring tank leaching was carried out to improve the bio-oxidation efficiency.Results show that bio-oxidation pretreatment can greatly improve the gold recovery rate of high-sulfur refractory gold concentrate,and at the optimum pH 1.3 in this study,compared with the process without pH control,the oxidation rate of sulfur increased from 79.31%to 83.29%,while the recovery rate of gold increased from 76.54%to 83.23%;under this condition the activity of mixed culture could be sustained and the formation of jarosite could diminish.The results also displayed that for the high sulfur refractory gold concentrate,the recovery of gold is positively correlated with the oxidation rate of sulfur,and the recovery rate of gold increases with the increase of sulfur oxidation rate within a certain range.

Effects of Traditional Chinese Medicine Leaching Solutions on Rice Yield

[Objective] The aim was to explore the effects of different leaching solu- tions on yield increasing of rice. [Method] Three rice parents were chosen from dif- ferent areas to treat with leaching solutions and rice leaves were sprayed with leaching solutions in seedling stage and tillering stage, respectively. The test data were recorded. Horizontal and vertical researches were carried out on agronomic traits of rice in different varieties in test or control groups. [Result] The horizontal test showed that hybrid rice parents, submerged with traditional Chinese medicines increased significantly in rice yield and vertical research indicated that rice in control group decreased sharply in yield and in test group improved in both yield and quality, which was also true for following generations. [Conclusion] The test provides references for hybrid rice maintaining rice traits.

Influence of Magnetic Treatment on Salts Leaching： From Soils of Different Salinity Levels

Leaching behavior of individual ions from three saline soils （S1 = 85.0 dS/m, S2 = 53.92 dS/m and S3 = 38.14 dS/m） under magnetic water （MW） treatment or non-magnetized well water （WW） was investigated in column study. After five pore volumes, soil electrical conductivity （EC） decreased to a range between 2.99-3.29 dS/m under the two water treatments. The rate of soluble cations leached was Na＋ 〉 Ca2＋ 〉 Mg2＋ 〉 K＋ and CI- 〉 SO42- 〉 HCO3- for anions under the two water treatments. The greater amount of salt leached was during the first two pore volumes and was higher under MW treatment. Among soils, the higher the initial EC, the greater the amount of the salt leached. Measurements of the exchangeable Na~ performed at the end of leaching experiment showed a high decrease in soil exchangeable Na＋ compared to the initial values of sodium adsorption ratio （SAR） and exchangeable sodium percentage （ESP） in the soil indicated that there was no prospects of soil sodification after leaching with five pore volumes.

Leaching kinetics of antimony-bearing complex sulfides ore in hydrochloric acid solution with ozone

The leaching kinetics of Sb and Fe from antimony-bearing complex sulfides ore was investigated in HCl solution by oxidation?leaching with ozone.The effects of temperature,HCl concentration,stirring speed and particle size on the process were explored.It is found that the recoveries of Sb and Fe reach86.1%and28.8%,respectively,when the reaction conditions are4.0mol/L HCl,900r/min stirring speed at85°C with<0.074mm particle size after50min leaching.XRD analysis indicates that no new solid product forms in the leaching residue and the leaching process can be described by shrinking core model.The leaching of Sb corresponds to diffusion-controlled model at low temperature(15?45°C)and mixed-controlled model at high temperature(45?85°C),and the apparent activation energies are6.91and17.93kJ/mol,respectively.The leaching of Fe corresponds to diffusion-controlled model,and the apparent activation energy is1.99kJ/mol.Three semi-empirical rate equations are obtained to describe the leaching process.

Oxygen pressure acid leaching of Gacun complex Cu concentrates

The treatment of the Gacun complex Cu concentrate with high contents of Pb,Zn,Ag,etc by oxygen pressure acid leaching was studied.It is unusual that tetrahedrite,whose treatment was rarely studied,is the primary copper mineral of the concentrates.Most of silver also occurs in the mineral.The optimum operating parameters of oxygen pressure acid leaching were established by conditional tests.Pilot scale test was carried out under the parameters,and the leaching rates of copper and zinc are as high as 97.10% and 89.83% while lead and silver are transformed into sulfate and sulfide respectively and stay in leaching residue.The copper and zinc in lixivium were reclaimed by extraction-electrowinning and purification-electrowinning,respectively,and the lead and silver in the residue were reclaimed separately by chloride leaching and thiourea leaching.The extraction rate of copper achieves 96%,and the leaching rates of lead and silver reach 90% and 95%,respectively.