Recovery Of Tin Research Articles

Recovery of Fine Cassiterite from Tin Tailings Slime by Froth Flotation

Tin gravity slime tailings of Datun mineral processing plant in south-eastern China contains fine and ultrafine cassiterite. Tin recovery from the slime tailings was studies in the presence of different flotation reagents. A flotation process has been used on a laboratory scale to investigate the effect of various reagents such as collectors, auxiliary collector, activators, ect., and theirs dosages in neutral flotation environment. To reach an optimum tin recovery, different dosages of the reagents were also studied. Due to cassiterite is friable and a large amount of fines and slimes were generated. Usually de-sliming is used to prevent slime coating and to increase the recovery of tin. However, analyses have shown that fine particles in the sample mostly contain tin, thus de-sliming was not suggested. By applying the process, ultrafine cassiterite can be efficiently recovered from the tailings slime by one rougher process, and the concentrate assaying 1.20% Sn with a recovery of 89.10% was obtained.

Beneficiation of Ultrafine Cassiterite from a Tin Tailings by Flotation

With the continuous depletion of primary tin ores, tin tailings has become an important source for the production of tin; however, the large-scale utilization of tin tailings is disappointedly scarce, due to its leanness in valuable minerals and insufficient methods available for processing such low-grade tailings. A flotation process has been used on a laboratory scale to investigate the effects of various reagents such as salicylhydroxamic acid, lead nitrate, sodium hexametaphosphate and pine oil on tin recovery at neutral pulp. Because cassiterite is friable and a large amount of fines and slimes were generated, usually de-sliming is used to prevent slime coating and to increase the recovery of tin. However, analyses have shown that fine particles in the sample mostly contain tin, thus de-sliming was not suggested. By applying the process, ultrafine cassiterite could be efficiently recovered from the slime tailings, and the concentrate assaying 1.82% Sn with a recovery of 76.90% was obtained.

바렐도금용 폐Steel Ball로부터 산화주석 및 금속주석 회수에 관한 연구

A study of the recovery of tin and nickel from steel ball scraps for barrel plating was carried out through a physical treatment, a leaching treatment, hydrogen reduction and an electrolysis experiment. The recovery of the iron component was over 95% by the physical treatment. We obtained tin oxide in the form of metastannic acid (SnO 2 ·xH 2 O) with impurities of less than 5% from the leaching treatment. We also recovered the high-purity metallurgical tin at a rate that exceeded 99.9% by the electrolysis of crude tin obtained from the hydrogen reduction of metastannic acid.

Experimental Research of Tin Ore from Kazakhstan

The paper recovered the tin from a refractory tin ore in Kazakhstan. The grade of tin in raw ore is 1.19%. Through technological mineralogy study, we found the tin was mainly in the forms of cassiterite and stannite. Considering the gravity process would make the stannite lost in tailings because of its small specific gravity, we explored the flotation to recover the tin. In fact, the grade and recovery of tin were bad by collectors contrast test. Finally, we adopted gravity flowsheet to recover cassiterite. The recovery of tin is not high because the tin in the form of stannite lost in tailings. As a result, the tin concentrate with a grade of 21.56% and the recovery of 52.90% were obtained.

Leaching studies for tin recovery from waste e-scrap

Printed circuit boards (PCBs) are the most essential components of all electrical and electronic equipments, which contain noteworthy quantity of metals, some of which are toxic to life and all of which are valuable resources. Therefore, recycling of PCBs is necessary for the safe disposal/utilization of these metals. Present paper is a part of developing Indo-Korean recycling technique consists of organic swelling pre-treatment technique for the liberation of thin layer of metallic sheet and the treatment of epoxy resin to remove/recover toxic soldering material. To optimize the parameters required for recovery of tin from waste PCBs, initially the bench scale studies were carried out using fresh solder (containing 52.6% Sn and 47.3% Pb) varying the acid concentration, temperature, mixing time and pulp density. The experimental data indicate that 95.79% of tin was leached out from solder material using 5.5M HCl at fixed pulp density 50g/L and temperature 90°C in mixing time 165min. Kinetic studies followed the chemical reaction controlled dense constant size cylindrical particles with activation energy of 117.68kJ/mol. However, 97.79% of tin was found to be leached out from solder materials of liberated swelled epoxy resin using 4.5M HCl at 90°C, mixing time 60min and pulp density 50g/L. From the leach liquor of solder materials of epoxy resin, the precipitate of sodium stannate as value added product was obtained at pH 1.9. The Pb from the leach residue was removed by using 0.1M nitric acid at 90°C in mixing time 45min and pulp density 10g/L. The metal free epoxy resin could be disposed-of safely/used as filling material without affecting the environment.

Partitioning of coal contaminants in the components of liquid tin anode solid oxide fuel cells

Direct carbon fuel cells (DCFCs) electrochemically convert fossil fuels to electricity, resulting in higher efficiency and less pollution than traditional direct combustion technologies. This work focuses on direct use of coal in a liquid tin anode solid oxide fuel cell (LTA SOFC) where a layer of molten tin functions as the anode. In such a direct solid fueling scheme, a major technical concern is the ultimate disposition of trace materials naturally present in the coal. Trace contaminants introduced with the coal must be located in the functional portions of the LTA SOFC to ensure that any deleterious reactions are known and ultimately mitigated. This research effort determines the thermochemical contaminant partitioning between the tin anode, slag, or electrolyte material and examines the critical interfaces within the system. Contaminant partitioning was examined by TEM, SEM/EDS, and ICP–OES/MS. Sulfur is known to poison yttria-stabalized zirconia (YSZ) and appears to form a tin sulfide phase that is dispersed in the liquid tin during operation. Results show that tin oxide formed on and near the YSZ electrolyte, and could potentially degrade charge transfer. The slag was found to consist of the expected metal oxides, however, tin and tin oxide were intermixed with the slag component, indicating a probable need for a tin recovery process that will potentially increase the complexity of an LTA SOFC system.

Modelling and process optimisation of antimony removal from a complex copper concentrate

The modelling and optimization for the alkaline sulphide leaching of a complex copper concentrate containing 1.69% Sb and 0.14% Sn were studied. Response surface methodology, in combination with central composite face-centred design (RSM-CCF), was used to optimise the operating parameters. The leaching temperature, sulphide ion concentration and solid concentration were chosen as the variables, and the response parameters were antimony and tin recovery, and the time required to achieve 90% Sb dissolution. It was confirmed that the leaching process was strongly dependent on the reaction temperature as well as the sulphide ion concentration without any significant dependence on the solid concentration. Furthermore, a mathematical model was constructed to characterise the leaching behaviour. The results from the model allow identification of the most favourable leaching conditions. The model was validated experimentally, and the results show that the model is reliable and accurate in predicting the leaching process.

Study on the New Technique for Micro-Particle Cassiterite of Dachang Tailings

The micro-particle cassiterite of Dachang tailings has been recovered by gravity concentration. The amplitude and frequency of strokes of table concentrator is optimized. The result of gravity concentration is that the grade of tin is 1.40%, and the recovery is 67.35%.Then, in the cassiterite reverse flotation, the new collector C08 was little used and the recovery of tin is achieved 90.05%

바렐도금용(鍍金用) Steel Ball 스크랩에서 주석(Sn) 및 니켈(Ni) 회수(回收)에 관한 연구(硏究)

A study on the recovery of tin from the steel ball scraps for barrel plating has been carried out the physical treatment and leaching experiment. The recovery of iron component was over 95% by the physical treatment, and the recovery of tin component was also over 95% by the hydro process.

Recovery of platinum, tin and indium from spent catalysts in chloride medium using strong basic anion exchange resins

This work describes a route for platinum recovery from spent commercial Pt and PtSnIn/Al 2O 3 catalysts using strong basic mesoporous and macroporous anion exchange resins (Cl − form). The catalysts were leached with aqua regia (75 °C, 20–25 min). Platinum adsorption was influenced by the presence of other metals which form chlorocomplexes (tin, indium) and also base metals (aluminum). However, it was possible to overcome this fact by a sequential desorption procedure. Aluminum was selectively removed from the resins by elution with 3 mol L −1 HCl. Platinum was desorbed passing 1 mol L −1 Na 2S 2O 3 (pH 9). Tin was removed by elution with 0.1 mol L −1 ascorbic acid. Indium was removed using 0.1 mol L −1 EDTA as eluent. Desorption efficiency exceeded 99% for all metals. Metals were recovered in high yields (>98 wt%).

Thermodynamics of Indium-Tin-Oxygen Ternary System

A new pyrometallurgical process for the recovery of metallic indium and tin from ITO scrap has been proposed based on the present thermodynamic study on the In-Sn-O ternary system. In the present study the phase relations and the equilibrium partial pressures of oxygen in the ternary system were determined at the temperature of 1173 K. Then by applying the Gibbs-Duhem equation to the phase relation of alloyoxide equilibrium, the activities of the components were obtained at 1173 K using the equilibrium partial pressures of oxygen. Moreover, the vapor pressures of indium and tin were calculated at temperatures of 1173 and 1400 K to discuss the proposed process. The process consists of two stages of reaction: first is the reduction of ITO by CO to In-Sn alloy at a low temperature. Second is the preferential vaporization of indium at a high temperature due to the three orders of magnitude difference between the vapor pressure of indium and that of tin. [doi:10.2320/matertrans.M-M2011806]

Separation of Sn, Sb, Bi, As, Cu, Pb and Zn from Hydrochloric Acid Solution by Solvent Extraction Process Using TBP (tri-n-Butylphosphate) as an Extractant

A basic study for the recovery of tin(Sn) from the scraps or plating sludges by a hydrometallurgical process was carried out. Tin was leached out by hydrochloric acid solutions and then separated from the mixed solution of co-leached miner metals such as, As, Sb, Bi, Cu, Zn and Pb for making high purity metal. A solvent extraction process was followed for the separation of tin and other minor metals from hydrochloric acid solution using TBP (tri-n-Butylphosphate) as the extracting reagent. Optimum conditions for the separation process were obtained using separation factors of tin versus each metal impurities derived at various concentrations of hydrochloric acid and sodium chloride in aqueous solution, and TBP in the organic solution. Scrubbing for metal impurities from the loaded organic solution was studied with different HCl concentrations. The study showed that Pb, Bi, Cu, Zn and Sb were quantitatively removed by scrubbing with 8.0 mol/L HCl from the organic phase after extracted in 6.0–7.0 mol/L HCl solution; As with 4.0 mol/L HCl solution from the organic phase after extracted in 3.0 mol/L HCl solution. From the integrated separation experiment by the simulate solution at 25 � C, 1.0 of O/A, and one stage contact at each extraction and purification step, the purity of finial Sn strip solution was 98.9% and the recovery of Sn was 67.9%. [doi:10.2320/matertrans.M2011142]

Recovery of tin and copper by recycling of printed circuit boards from obsolete computers

This paper presents the experimental results for the leaching of printed circuit boards (PCB) from obsolete computers for extracting and recovering tin and copper by means of leaching followed by precipitation. Printed circuit boards were dismantled, cut into small pieces, and fed into a cylinder mill. The powder obtained was leached by using the aqueous solutions 2.18N H2SO4, 2.18N H2SO4 + 3.0N HCl, 3.0N HCl, and 3.0N HCl + 1.0N HNO3. The lowest values for the percentage of metal extraction were obtained with 2.18N H2SO4 (2.7% for Sn and lower than 0.01% for Cu), while the 3.0N HCl + 1.0N HNO3 leach system exhibited an extraction of 98% for Sn and 93% for Cu. Precipitates were obtained at different pH values by neutralizing the leach liquors using NaOH. The 3.0N HCl + 1.0N HNO3 leach system presented the highest recovery values from the powder feed (84.1% for Sn and 31.9% for Cu), as well as from the leach liquor (85.8% for Sn and 34.3% for Cu).

The recovery of copper and tin from waste tin stripping solution: Part II: Kinetic analysis of synthetic and real process waste

Tin stripping is a key process step in printed circuit board fabrication. At the end of a tin stripping process, in general, metal concentration in the waste is 2–40 g/l Cu and 150 g/l SnO 2 [D. McKeeson, Print. Circuit Fabr. 22 (7) (1999) 34–37] in addition to nitric acid, ferric ions and other complexants. In a previous work we had carried out a thermodynamic analysis to determine if copper can be recovered from a tin stripping process. In this paper we present a kinetic analysis to determine the current efficiency for copper electrodeposition from a tin strip waste solution. We have performed electrochemical stripping analysis from simulated and real waste tin strip solutions. Copper is electrodeposited from solutions containing only copper and nitric acid, copper and nitric acid with ferric and tin ions, or waste from tin-strip processes. Our results showed that copper can be recovered at reasonably high current efficiency from solutions containing nitrate ions. The presence of ferric ions, however, reduces current efficiency significantly. It was shown that the tin stripping solution is a mixed potential system. In order to develop a high efficiency electrochemical copper recovery system, the crucial criteria are to maintain a low concentration of ferric ions in solution and to suppress the generation of ferric ions by electro-oxidation.

The Recovery of Copper and Tin from Waste Tin Stripping Solution Part II: Kinetic Analysis

In a previous work we had carried out a thermodynamic analysis to determine if copper can be recovered from a tin stripping process (1). In this paper we present a kinetic analysis to determine the current efficiency for copper electrodeposition from a tin strip waste solution. We have performed electrochemical stripping analysis to from simulated and real waste tin strip solutions. Copper is electrodeposited from solutions containing only copper and nitric acid, copper and nitric acid with ferric and tin ions, or waste from tin-strip processes. Our results show that copper can be recovered at reasonably high current efficiency from solutions containing nitrate ions. The presence of ferric ions, however, reduces current efficiency significantly.

Recovery of Tin from Waste Solution : The Influence of Temperature, Time and Current Density

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The recovery of copper and tin from waste tin stripping solution: Part I. Thermodynamic analysis

Stripping solutions containing suspended tin and dissolved copper and iron, are a by-product of printed circuit board manufacture. The recovery of these metals for reuse has economic and environmental benefits. By focusing on this waste stream, a systematic method to determine the process of metal recovery has been developed. Initially the thermodynamics of the system were examined. E–pH diagrams were constructed to ascertain whether metals would be in the solid or liquid phase depending on the ionic concentrations, pH and system potential. Simulations using MINEQL+ were also performed to account for ionic strength. The validity of this thermodynamic study was tested by determining the precipitation pH of the metal solutions. The study showed that the dissolved copper and suspended tin oxide could be separated by filtration if the pH was maintained between −0.4 and 2.4. The dissolved copper could then be removed by electrodeposition, leaving iron in solution.

Electrochemical study of the activating solution for electroless plating of polymers

This paper presents an electrochemical study about the activating solutions of the electroless plating of polymers, containing Pd(II), Sn(II) and Sn(IV) mixtures in HCl as main components. The objective of the study is the voltammetric characterization of these solutions by cyclic and linear voltammetry in order to study the recovery of tin and palladium from these solutions. The effect of concentration and rotation rate on the current−potential curves was studied using the RDE technique. The electrochemical behaviour of solutions prepared in the laboratory was performed as a prior step to the further study of real activating rinsing solutions. The electrochemical reduction of Pd(II) takes place in two one-electron transfer steps which are mass transport controlled. The electrochemical reduction of Sn(II) and Sn(IV) is also mass transport controlled and takes place with direct formation of metallic tin, although the electrochemical reduction of Sn(IV) only takes place in solutions with HCl concentrations higher than 1 M. The presence of additives in the real solutions prevent the chemical reduction of Pd(II) and the formation of Sn(IV) hydroxylated complexes. This causes the appearance of well defined diffusion waves attributable to the electrochemical reduction of Pd(II) and Sn(IV). Hence, the recovery of both species simultaneously as well as separately could be carried out, if appropriate conditions are selected.

リサイクリング・プロセスと操業 生野事業所におけるすず製錬

The Ikuno tin smelter has started its operation in 1913, followed by tin refinery in 1916. Originally, the reverberatory furnace had been used for smelting, but later it was replaced by the present electric furnace in order to improve productivity and increase tin recovery. The refinery was relocated from Ikuno to Osaka in 1920, and then again relocated to Naoshima in 1960.The present refinery in Ikuno has started operation in 1991. After Akenobe mine was closed in 1987 due to low tin price and its poor mining condition, domestic secondary materials from the market has been purchased and treated. At present, Ikuno plant is the only producer of electro-refining tin in Japan and 65t/month of electric-tin has been produced.

Optical and Chemical Methods of Metal Ash Analysis and Tin Recovery

'Metal ash' presents a waste disposal problem in most of the developing countries as the industries employ obsolete technologies. In this paper we describe analysis of tin ash, zinc ash and aluminium ash by means of optical methods, such as X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), electron probe micro analysis (EPMA), scanning electron microscopy (SEM) and chemical methods. The results of tin ash obtained by XRD method matched well with the cassiterite, a naturally occurring mineral of tin. ICP-MS studies reveal the presence of a large number of tracer metals, which may cause pollution by tertiary dispersion and this aspect is discussed. Conversely, the data generated by chemical methods are limited. However, the methods are simple and cost-effective. Then, they can easily be adopted by low-budget industries. Simple and cost-effective process to recover tin from tin ash is described. It is based on heating tin ash with sodium cyanide to about 900 degrees C to separate tin component from the metal ash. The process recovers good quality tin and offers a very high yield. The process can be scaled up to small pilot plant.