Alkaline leaching of metal melting industry wastes and separation of zinc and lead in the leach solution

In this work, a thorough examinations on the extractability of zinc and lead present in the steelmaking dusts using alkaline leaching process and the effectiveness of the zinc and lead separation in the resultant leaching solutions using sulfide precipitation method were made. It was found that only about 53% of zinc and over 70% of the lead could be leached out of the dusts, while the other 47% of zinc and 30% of lead were left in the leaching residues. The zinc and lead in the resultant leaching solution can be effectively and selectively separated. When the weight ratio of sodium sulfide (M.W. = 222-240) to Pb was kept at 1.8, the lead in the solution could be precipitated out quantitatively while all the zinc was remained in the solution. The zinc left in the solution can be further recovered by the addition of extra sodium sulfide with a weight ratio of sodium sulfide to the zinc over 2.6. The resultant filtrate can be recycled to the leaching of dust in the next leaching process.

The mechanisms of paragenesis and separation of silver, lead and zinc in hydrothermal solutions

On the basis of an experimental study and thermodynamic calculation, the mechanisms of paragenesis and separation of silver, lead and zinc in the hydrothermal system have been studied. At acidic to nearly neutral pH, their chloride complexes are stable, and among them the chloride complexes of zinc are most stable. And the sulfide complexes are the dominant species at nearly neutral to alkaline pH, while the sulfide complexes of silver are most stable. With decreasing temperature, , f-{O-2} and increasing pH, the solubilities of silver, lead and zinc will decrease, leading to their deposition and separation. For sulfide complexes, the concentrations of reduced sulfur and pH are two important factors affecting their stabilities. Complexes of different forms and stabilities respond to the variation of conditions to different extents, which gave rise to the paragenesis and separation of silver, lead and zinc in the whole ore-forming process of dissolution, transport and deposition.

Interphase migration and enrichment of lead and zinc during copper slag depletion

An interphase migration and enrichment model of lead and zinc during molten copper slag depletion was established.The occurrence of various components in copper slag was predicted using sulfur-oxygen potential calculations and confirmed through high-temperature experiments.The recovery rate of copper can reach 90.13%under the optimal conditions of 1200°C,an iron to silicon mass ratio of 1.0,3 wt.%ferrous sulfide,and a duration of 45 min.Lead(54.07 wt.%)and zinc(17.42 wt.%)are found in the flue dust as lead sulfate,lead sulfide,and zinc oxide,while copper matte contains lead(14.44 wt.%)and zinc sulfide(1.29 wt.%).The remaining lead and zinc are encapsulated as oxides within the fayalite phase.

Analysis of Oxygen Consumption in Lead and Zinc Metallurgy

This article analyzes the role of oxygen in lead zinc metallurgy,including shortening the metallurgical process,promoting energy conservation and environmental protection,improving metallurgical strength,enhancing raw material adaptability,and enhancing comprehensive recovery efficiency.This article introduces different lead zinc metallurgical processes and their oxygen consumption characteristics,including oxygen enriched side blowing lead smelting,oxygen bottom blowing lead smelting,oxygen enriched top blowing lead smelting,flash smelting lead,oxygen pressure leaching zinc smelting,and atmospheric pressure oxygen leaching zinc smelting.It is pointed out that oxygen enhanced metallurgy is the direction for the transformation and upgrading of lead zinc metallurgy.

Effects of field application of phosphate fertilizers on the availability and uptake of lead, zinc and cadmium by cabbage (Brassica chinensis L.) in a mining tailing contaminated soil

A field trial was conducted to evaluate the reduction of bioavailability of heavy metals including lead (Pb), zinc (Zn) and cadmium (Cd) in a soil contaminated by mining tailings in Shaoxing, Zhejiang, China. Three commercial phosphate (P) fertilizers including phosphate rock (PR), calcium magnesium phosphate (CMP), and single superphosphate (SSP) were applied to the plot at three P application rates, 50, 300, and 500 g/m2 with 9 treatments and control (CK). Plants, water soluble and exchangeable (WE) extra...

Recovery of zinc and lead from Yahyali non-sulphide flotation tailing by sequential acidic and sodium hydroxide leaching in the presence of potassium sodium tartrate

The recovery of zinc and lead from Yahyali non-sulphide flotation tailing using sulfuric acid followed by sodium hydroxide leaching in the presence of potassium sodium tartrate was experimentally investigated.In the acidic leaching stage,the effects of pH,solid-to-liquid ratio and temperature on the dissolution of zinc from the tailing were explored.82.3%Zn dissolution was achieved at a pH of 2,a temperature of 40°C,a solid-to-liquid ratio of 20%and a leaching time of 2 h,whereas the iron and lead dissolutions were determined to be less than 0.5%.The sulfuric acid consumption was found to be 110.6 kg/t(dry tailing).The leaching temperature had no beneficial effect on the dissolution of zinc from the tailing.The acidic leach solution was subjected to an electrowinning test.The cathode product consisted of 99.8%Zn and 0.15%Fe.In the alkaline leaching stage,the Pb dissolution increased slightly in the presence of potassium sodium tartrate.More than 60%of Pb was taken into the leach solution when the leaching temperature increased from 40 to 80°C.The final leach residue was analyzed by XRD and XRF.The XRD results indicated that the major peaks originated from the goethite and quartz while minor peaks stem from smithsonite and cerussite.The XRF analysis demonstrated that the residue contained 70.3%iron oxide.Based on the sequential leaching experiments,the zinc and lead were excellently depleted from the flotation tailing,leaving a considerable amount of iron in the final residue.

Study on the response of wheat to lead, cadmium and zinc

The effect of lead, cadmium and zinc on the transcriptions and structures of 5 DNA fragments was studied by RNA slot blot hybridization and the analysis of restriction fragment length polymorphism (RFLP). The seeds of three wheat strains (Yunmai29, 1257, 5118) which had grown in contaminated area, Huize Lead Zinc Mine, Yunnan Province of China and in uncontaminated area were taken as the experimental materials. No obvious change of DNA structure was detected, but there were many differences in the DNA transcription levels. These results implied that lead, cadmium and zinc might inhibit DNA transcription and had much more effect on gene expression than structure in wheat, which might acclimate to metal pollution after having grown in pollution area for a long time and the interference of these metal ions in gene expression might be one of main mechanisms of metal toxicity and plant adaptation. The results also showed the microevolution of wheat in the lead zinc mine.

Heavy metal concentrations in soils and plants in the vicinity of Arufu lead-zinc mine, Middle Benue Trough, Nigeria

This study focused on the influence of base metal mining on heavy metal levels in soils and plants in the vicinity of Arufu lead-zinc mine, Nigeria. Soil samples (0-15 cm depth) and plant samples were collected from cul-tivated farmlands in and around the mine, the unmineralized site and a nearby forest (the control site). The samples were analyzed for heavy metals (Fe, Zn, Mn, Cu, Pb, Cr and Cd) by Atomic Absorption Spectrophotometry (AAS). The physical properties of soils (pH and LOI) were also measured. Results showed that soils from cultivated farm-lands have neutral pH values (6.5-7.5), and low organic matter contents (<10%). Levels of Zn, Pb and Cd in culti-vated soils were higher than the concentrations obtained from the control site. These heavy metals are most probably sourced from mining and agricultural activities in the study area. Heavy metal concentrations measured in plant parts decreased in the order of rice leaves>cassava tubers>peelings. In the same plant species, metal levels decreased in the order of Zn>Fe>Mn>Cu>Pb>Cr>Cd. Most heavy metals were found in plant parts at average concentrations normally observed in plants grown in uncontaminated soil, however, elevated concentrations of Pb and Cd were found in a few cassava samples close to the mine dump. A stepwise linear regression analysis identified soil metal contents, pH and LOI as some of the factors influencing soil-plant metal uptake.

Isotopic Compositions of Sulfur in the Jinshachang Lead–Zinc Deposit, Yunnan, China, and its Implication on the Formation of Sulfur-Bearing Minerals

The Jinshachang lead-zinc deposit is mainly hosted in the Upper Neoproterozoic carbonate rocks of the Dengying Group and located in the Sichuan-Yunnan-Guizhou （SYG） Pb-Zn-Ag multi- metal mineralization area in China. Sulfides minerals including sphalerite, galena and pyrite postdate or coprecipitate with gangue mainly consisting of fluorite, quartz, and barite, making this deposit distinct from most lead-zinc deposits in the SYG. This deposit is controlled by tectonic structures, and most mineralization is located along or near faults zones. Emeishan basalts near the ore district might have contributed to the formation of orebodies. The j34S values of sphalerite, galena, pyrite and barite were estimated to be 3.6‰-13.4‰, 3.7‰-9.0‰, -6.4‰ to 29.2‰ and 32.1‰34.7‰, respectively. In view of the similar δ34S values of barite and sulfates being from the Cambrian strata, the sulfur of barite was likely derived from the Cambrian strata. The homogenization temperatures （T ≈ 134--383℃） of fluid inclusions were not suitable for reducing bacteria, therefore, the bacterial sulfate reduction could not have been an efficient path to generate reduced sulfur in this district. Although thermochemical sulfate reduction process had contributed to the production of reduced sulfur, it was not the main mechanism. Considering other aspects, it can be suggested that sulfur of sulfides should have been derived from magmatic activities. The δ34S values of sphalerite were found to be higher than those of coexisting galena. The equilibrium temperatures calculated by using the sulfur isotopic composition of mineral pairs matched well with the homogenization temperature of fluid inclusions, suggesting that the sulfur isotopic composition in ore-forming fluids had reached a partial equilibrium.

Study on the multi-sources of ore-forming materials and ore-forming fluids in the Huize lead-zinc ore deposit

The Huize large-sized Pb-Zn deposit in Yunnan Province, China, is characterized by favorable metallogenic background and particular geological settings. This suggested that the ore-forming mechanism is relatively unique. On the basis of geological features such as the contents of mineralization elements, the REE concentrations of gangue calcites, the REE concentrations of calcite veins in the NE-trending tectonic zone and the Pb, Sr, C, H and O isotopic compositions of different minerals, this paper presents that the ore-forming materials and ore-forming fluids of the deposit were derived from various types of strata or rocks. This is a very significant conclusion for us to further discuss the mineralization mechanism of the deposit at depth and establish an available genetic model.

Estimation of lead and zinc emissions from mineral exploitation based on characteristics of lead/zinc deposits in China

Nonferrous mining activities are some of the largest sources of heavy metals emissions into the environment and China is one of the largest producers and consumers of lead and zinc in the world.The cumulative productions and emissions of lead and zinc from mining-related activities in China were estimated.Up to 2007,the cumulative productions of lead and zinc in China were estimated to be about 6.69 and 12.59 Mt,respectively;and about 1.62 Mt lead and 3.32 Mt zinc emitted into the ambient environment during the mining,processing and smelting activities,representing 24.39% and 26.36% cumulative production,respectively.Among these three types of mining-related activities,mineral processing contributes the most to the total emission of 50.67% lead and 45.51% zinc.

Study on experiment and mechanism of thermal dissolved sulfuration of low grade lead-zinc oxide ore in lanpin

The thermal dissolved sulfuration technology is brought forward and performed based on the characteristic of low grade lead-zinc oxide ore in lanpin. Using sulfur as the sulphidizing agent in the experiment, the oxides in the sandstone and ignimbrite are changed into sulfides. The disproportionation reaction of sulfur in a solution is confirmed as 4S＋3H2O=2S^2-＋S2O3^2--＋6H^＋. The dynamics process is studied and the first-order reaction rate equation -1n（1-a）=ktt is obtained. The effects of the reactive products, stirring speed, dosage of sulfuration agent, value of pH and sulphidizing temperature on the sulfuration of oxide ore are investigated. The results indicate that the reactive apparent activation energy is 100.8 kJ/mol and the sulfuration ratio of lead-zinc oxide ore reaches 60% under the conditions of pH 5.9-7.5, the sulfuration temperature of 130 ℃, sulfuration time of 180 min and the stirring speed of 800 r/min.

Analysis and Evaluation of Bioavailable Heavy Metals in Surface Soil of the Abandoned Lead-zinc Mine in Changhua,Hainan Province

[Objectives] The research was conducted to study characteristics of bioavailable levels pollution of heavy metals in the surface soil of the lead-zinc mine in Changhua.[Methods] A total of 56 surface samples were collected from the 3 study zones （peripheral zone, reclamation zone and tailing zone） located at the lead-zine mine in Changhua. Based on total and bioavailable heavy metals （Pb, Zn, Cu and Cd） in soils, the correlation of total content with bioavailable content was analyzed, and their pollution characteristics were assessed by methods of single factor pollution index, Nemerow pollution index, geological accumulation index and potential ecological risk index.[Results] （i） The surface soils were polluted by Pb, Zn, Cu, Cd in different degrees, and the overall trend of the contents of the 4 heavy metals was in order of Cd 〉 Pb 〉 Zn 〉 Cu. The average excess multiple of heavy metals of total and bioavailable content in soils were in the order of peripheral zone 〉 tailing zone 〉 reclaimed zone, and their pollution degrees were tailing zone 〉 peripheral zone 〉 reclaimed zone. （ii） In general, the total and bioavailable contents of Pb, Zn, Cu, Cd showed a significant correlation, but were not correlated in each study zone. （iii） Pollution degrees of the study zones were in the order of tailing zone 〉 peripheral zone 〉 reclamation zone. The pollutions of heavy metals Pb and Cd were more serious, especially Cd reached high levels of pollution degree, and the pollution degrees of Zn, Cu were lighter. Contributors of ecological risk were mainly Cd, Pb and Cu, and the contribution of Cd achieved more than 90 %, making it the main source of pollution.[Conclusions] The results not only revealed the pollution status of heavy metals in the surface soil of the abandoned coal mine, but also could provide scientific guidance for reasonable utilization and ecological recovery of the land.

New Constraints on the Environmental Impact of Iron Oxides and Lead-Zinc Mines in Red Sea Hills,Egypt

Iron oxides and lead-zinc deposits in host rocks located in ten drainage basins in the coastal plain of the Red Sea,Egypt,have been subjected to important mining activities.The drainage basins were analyzed to estimate the transportations of these minerals. Fourteen soil samples and fifteen plant samples were collected from sites located in the basin and also in neighboring area and chemically analyzed.In

Effects of Cadmium, Lead, and Zinc on Size of MicrobialBiomass in Red Soil

A laboratory incubation experiment was conducted to study the influence of cadmium (Cd), lead (Pb)and zinc (Zn) on the size of the microbial biomass in red soil. All the three metals were applied, separately,at five different levels that were: Cd at 5, 15, 30, 60 and 100 μg g-1; Pb at 100, 200, 300, 450 and 600 μg g-1 and Zn at 50, 100, 150, 200 and 250 μg g-1 soil. In comparison to uncontaminated soil, the microbial biomass carbon and biomass nitrogen decreased sharply in soils contaminated with Cd, Ph and Zn. A more considerable increase in the microbial biomass C: N ratio was observed in the metal contaminated soils than the non-treated control. Among the tested metals, Cd displayed the greatest biocidal effect followed by Zn and Pb, showing their relative toxicity in the order of Cd > Zn > Pb.

Sulfidation roasting of lead and zinc carbonate with sulphur by temperature gradient method

In order to enhance the lead and zinc recovery from the refractory Pb-Zn oxide ore, a new technology was developed based on sulfidation roasting with sulphur by temperature gradient method. The solid-liquid reaction system was established and the sulfidation thermodynamics of lead and zinc carbonate was calculated with the software HSC 5.0. The effects of roasting temperature,molar ratio of sulphur to lead and zinc carbonate and reaction time in the first step roasting, and holding temperature and time in the second roasting on the sulfidation extent were studied at a laboratory-scale. The experimental results show that the sulfidation extents of lead and zinc are 96.50% and 97.29% under the optimal conditions, respectively, and the artificial galena, sphalerite and wurtzite were formed. By the novel sulfidizing process, it is expected that the sulphides can be recovered by conventional flotation technology.

Separation of indium (Ⅲ), gallium (Ⅲ), and zinc (Ⅱ) with Levextrel resin containing di(2-ethylhexyl) phosphoric acid (CL-P204): Part I. Selection of separation conditions

A kind of Levextrel resin separation process was developed for separation ofindium (III), gallium (III), and zinc (II) from aqueous sulfate solution with Levextrel resincontaining di(2-ethylhexyl) phosphoric acid (CL-P 204). The aim of the research is to collectpreliminary results for a pilot-scale production. Properties of adsorbing indium (III), gallium(III), and zinc (II) from sulfate solution with the Levextrel resin were first studied by batchoperation and column operation. The optimum pH, adsorption capacities and concentrations ofstripping agents for indium (III), gallium (III) were tested. The separation order of indium (III),gallium (III), and zinc (II) from sulfate solution with CL-P 204 Levextrel resin was found thatindium (III) could be first separated by adsorbing at the acidity of 1.0 mol/L whereas gallium (III)and zinc (II) could not, and they were adsorbed together by adsorbing at pH =2.8, then separatedfrom each other by stripping with 0.1 and 0.5 mol/L hydrochloric acid, respectively. The recoveriesof three metal ions were all higher than 99 percent. The cyclic properties of this resin are well.

Effects of EDTA and DTPA on Lead and Zinc Accumulation of Ryegrass

The tailing ponds of lead-zinc mines are artificial environment pollution sources, and also important dangerous sources of heavy metal contamination in lead-zinc mining areas. To study the effects of Ethylene Diamine Tetracetic Acid (EDTA) and Diethylene Triamine Penlaacetic Acid (DTPA) on phytoremediation of lead-zinc mining area soil, two chelators (EDTA and DTPA) were used in enrichment plant ryegrass to improve the uptake of Pb and Zn from soil. The results showed that when the doses of 0, 0.5, 1 and 2 mmol/kg EDTA and DTPA were used, the biomass of ryegrass (Lolium multiflorum Lam.) and its nutrient (N, P, K, Ca and Mg) content increased, whereas EDTA and DTPA with a dose of 4 mmol/kg decreased the biomass of ryegrass and its nutrient (N, P, K, Ca and Mg) content. EDTA and DTPA significantly enhanced the contents of Zn and Pb in ryegrass as compared with the control. As for Pb, the content of Pb in root and shoot reached a maximum of 2730.54 and 2484.42 mg/kg respectively when the dose of EDTA and DTPA was 2 mmol/kg. In the case of Zn, the content of Zn in root and shoot reached a maximum of 2428.37 and 2010.43 mg/kg respectively. The total Pb and Zn accumulations and translocation ratio in ryegrass had also been enhanced. The results indicated that EDTA and DTPA had great potential to be used for ryegrass to remedy Pb and Zn contamination soil of lead-zinc mining area, but should be used cautiously because of their environmental risks.

Sulphidization flotation for recovery of lead and zinc from oxide-sulfide ores

A new flowsheet was developed to recover the valuable minerals from oxide or oxide-sulfide ores of lead and zinc. The flowsheet consisted of flotation of sulfide minerals, desliming and sulphidization-flotation of oxide minerals. The corresponding reagent system and techniques to the flowsheet were investigated. Batch and continuous tests show that the dosage of sodium sulfide, temperature, and collector type are main affecting factors on the recovery of smithsonite and cerussite. For the flotation of cerussite, there is an appropriate dosage of sodium sulfide at which the recovery reaches its maximum value. The required sodium sulfide for smithsonite flotation is higher than that for cerussite and the recovery of smithsonite flotation increases with the dosage of sodium sulfide at low level and becomes insensitive at high dosage. The appropriate temperature for smithsonite and cerussite flotation is found to be 2540℃. Amines are found to be the effective collectors for the flotation of smithsonite after sulphidization. Investigation also shows that desliming prior to sulphidization-flotation is essential to the effective recovery of smithsonite and cerussite, and the desliming process of two-stage hydrocyclon is well feasible and effective for the treatment of lead-zinc oxide ores. A further treatment on the cerussite flotation concentrate by shaking table is proposed to obtain higher lead grade.

A novel hydrothermal method for zinc extraction and separation from zinc ferrite and electric arc furnace dust

A novel hydrothermal process was developed to extract zinc from pure zinc ferrite（ZnFe2O4） nanopowder and zinc-containing electric arc furnace（EAF） dust using hexahydrated ferric chloride（FeCl3-6H2O） as a decomposing agent.The effects of solid FeCl3-6H2O to ZnFe2O4 ratio by mass（RF/Z）,hydrothermal reaction temperature,and time on zinc extraction were systematically investigated.In the results,when the hydrothermal reaction is conducted at 150℃ for 2 h with RF/Z of 15：20,the efficiency of zinc extraction from ZnFe2O4 reaches97.2%,and the concentration of ferric ions（Fe^3＋） in the leaching solution is nearly zero,indicating a high selectivity for zinc.In addition,the zinc extraction efficiency from the EAF dust reaches 94.5%in the case of the hydrothermal reaction performed at 200℃ for 10 h with the solid FeCl3-6H2O to EAF dust ratio by mass（RF/EAF dust） of 15：10.Zinc and iron separation is achieved by adjusting the pH value of the leaching solution according to the different precipitation pH values of metal hydroxides.