Leaching of lead from solder material used in electrical and electronic equipment

Present work is a part of developing novel recycling tec-hnique for waste printed circuit boards (PCBs) i.e. the liberation of metals from PCBs by organic swelling follow-ed by the treatment of resin to remove/ recover hazardous soldering materials. In order to recover the hazardous metallic constituent lead from the liberated resin, init-ially the leaching studies were made using fresh solder co-ntaining 63.9% Pb and remaining tin. Experimental results obtained in different conditions viz. time,temperature and acidity showed ~97.20% of lead dissolution with 6M HNO3 at solid to liquid (S:L) ratio 1:10 (g/mL) and temperature 90oC in 75 minutes. The result of the studies validated with crushed PCBs shows that almost total lead and tin was leached out with 6M HNO3 and 6M HCl respectively at S:L ratio 1:10 (g/mL) and temperature 90oC within 50 minutes. The results will be useful for the treatment and safe dis-posal of PCBs resin

Potential hydrometallurgical processes to recycle metals from discarded personal computer

Rapid technological modernization has accelerated the replacement of older electronic goods with newer ones, which has led to the generation of huge quantities of discarded electronic items at their end-of-life, known as electronic waste (e-waste). The growing quantity of e-waste has become a major threat to the society as well as the environment. On the other hand, e-waste contains several valuable metals and materials of high economic value, which compels researchers to work in the area for secondary resources for metal recovery. Metal recovery from such secondary resources will not only preserve the primary resources but also reduce the loss of valuable metals/materials, protect the environment from their hazardous effects as well as reduce the demand-supply gap of metals up to some extent. In view of the above, the present study is focused on the possible effort to figure out a variety of metals present in the component of waste personal computers (WPCs) as well as different recycling processes implemented for the efficient recovery of metals

Extraction and recovery of nitric acid and copper from leach liquor of waste PCBs

The disposal of large quantities of electronic scrap world wide is causing an enormous harm to environment as well as to mankind. Therefore, efforts have been made to develop a suitable hydrometallurgical process for the extraction of metals from electronic scraps.The leach liquor of waste PCBs was generated containing 18.78g/LCu, 0.38g/LFe, 0.13g/LNi, 1.34g/L Pb and 6.3 M HNO3. Initially, HNO3 was extracted from the leach liquor using TBP as an extractant. Various process parameters such as time, concentration of extractant, O/A ratio etc were studied for the extraction of HNO3. It was observed that the extraction of HNO3 increased from 8.1–39.6% with increase in TBP concentration from 10 to 100%. The plot of log D vs. log[TBP] gives a straight line with slope ~ 1indicated that the 1 mole of TBP used for the extraction of 1mole of HNO3. The McCabe – Thiele Plot was drawn to investigate the stage required for maximum acid extraction. After extraction of HNO3 from leach liquor, extraction of copper was investigated using LIX84IC. Various parameters such as effect of pH, phaseratio, strippingetc. Were studied to investigate the optimum experimental condition for the extraction of copper. The extraction of Cu increased from 37 to 88% with the increase in the Ph range from 0.7 to 2.0. The optimum equilibrium pH for Cu extraction was found to be ~2.0. The McCabe– Thiele Plot for Cu extraction indicated that 2 counter current stages is enough for its complete removal from acid free leach liquor at O/A=1.2/1 maintaining equilibrium pH~2.0. The present study reports removal of acid and Cu from the leach liquor of waste PCBs in an eco-friendly manner

Reclamation of Copper from Electronic Industry Effluent Using Plant Root Adsorbent

Copper ion contamination in electronic industrial effluent is a universal issue. The traditional way of copper removal from effluent has some disadvantages like expensive operational costs, and sludge generation after water treatment. Adsorption technique for copper(II) using synthetic adsorbent is one of the efficient ways of water treatment but it is expensive on a commercial scale. Due to this, researchers across the globe are looking after to find an efficient, economical, and readily available biomass-based adsorbent for metal recovery. The present study was intended for the adsorption of copper onto Datura ( ) root powder using batch studies. It was found to be one of the efficient bio adsorbents with 947 mg/g copper adsorption capability. Batch experiments were performed by using 4 g/L of Datura root powder kept in contact with 100 ppm copper containing industrial effluent in 15 min contact time at pH 4. The result indicates 95% copper adsorption on the surface of Datura root powder. Kinetic study indicates that experimental data fit well in pseudo second-order rate reaction and follows Freundlich isotherm indicating multilayer adsorption process. FT-IR result indicates involvement of aromatic group (Phosphates) of Datura root binding with copper ions. Elution experiments were performed using 10% H SO in 60 min to remove copper from the loaded adsorbent. The high copper adsorption capacity and the regeneration efficiency of Datura root powder suggest its applicability in copper reclamation from electronic industrial effluent

Recycling of Nd-Fe-B Magnets to Reclaim Nd Salt and Pigment

Hard disk of computers is the most essential part, which plays significant role for programming the computers. Hard disk contains permanent Nd-Fe-B magnet as a most powerful magnet, these magnets become waste rapidly by reaching its end-of-life, therefore the metallic content (Nd, Pr, Dy) in it is also act losses which is present in limited stock in nature therefore recycling of these waste is necessary to get the metallic content from it and also preserve the natural resources. This study provide a proper technique and development of hydrometallurgical process to extract REMs from Nd Fe B magnets, which includes general flow chart such as manual dismantling, demagnetization (300 °C, 3h), crushing to get the material in its homogenous form, leaching (2M H SO , 100 g/L, 25 °C, 1h), solvent extraction of REMs (pH~2, 15 min), air sparging to remove iron from the solution (pH~3.5, 50-60 °C, 1h), etc. about >95% of rare earth metals were recovered by this techniques and remaining metals left in the liquor can be recovered by further hydrometallurgical processes

Recovery of Nickel from Waste Printed Circuit Boards of Personal Computers

Present study reports, the application-oriented process for the recovery of nickel from printed circuit boards (PCBs) of scrap personal computers. The PCBs were initially depopulated, crushed, pulverized, and beneficiated to get the metallic concentrate. The concentrate was further processed by hydrometallurgical leaching and solvent extraction processes to extract nickel and copper. At first, leaching studies were carried out in sulphuric acid at different process parameters such as acid concentration, reaction time, temperature, etc., to dissolve the metals. Results show that 99% of Ni and Cu was leached in 20% H SO at 75°C for 2 h maintaining the pulp density of 100 g/L in the presence of 20% H O . The obtained leach liquor was further processed by solvent extraction technique to separate the Cu and Ni. It was found that 99% Cu and Ni were selectively extracted with LIX-984 N at pH: ±2.5 and ±4.5, respectively. Electrolysis, evaporation and crystallization processes could be used to obtain the pure metal and its salt from the pure metallic solutions

Pyrolysis Pre-treatment of PCBs: A Sustainable Solution to Convert Encapsulation into Marketable Product and Separation of Metallic Concentrate

Printed circuit boards (PCBs) are the essentially required component of all the electronic goods, containing a variety of metals. PCBs are made up of several layers of epoxy resins, thin metallic sheets, etc. The metallic sheet encapsulated with resin hinders the hydrometallurgical metal dissolution process. The mechanical pre-treatment process is not feasible due to high energy consumption and non-availability of a compatible machine. Therefore, pyrolysis studies were conducted for the removal of capsulation of resin on metals present in PCBs. Various experimental parameters were studied to optimize the pyrolysis process. The gas generated during the pyrolysis was condensed to get Low Density Oil (LDO).And the metal depleted poly-cracked carbon was converted to activated carbon and the metallic fractions processed for metal recovery using hydrometallurgy. The process has potential for commercialization after feasibility studies

Application of Environmental Friendly Bio-adsorbent based on a Plant Root for Copper Recovery Compared to the Synthetic Resin

Copper is one of the non-ferrous metals used in the electrical/electronic manufacturing industries due to its superior properties particularly the high conductivity and less resistivity. The effluent generated from the surface finishing process of these industries contains higher copper content which gets discharged in to water bodies directly or indirectly. This causes severe environmental pollution and also results in loss of an important valuable metal. To overcome this issue, continuous R & D activities are going on across the globe in adsorption area with the purpose of finding an efficient, low cost and ecofriendly adsorbent. In view of the above, present investigation was made to compare the performance of a plant root (Datura root powder) as a bio-adsorbent to that of the synthetic one (Tulsion T-42) for copper adsorption from such effluent. Experiments were carried out in batch studies to optimize parameters such as adsorbent dose, contact time, pH, feed concentration, etc. Results of the batch experiments indicate that 0.2 g of Datura root powder and 0.1 g of Tulsion T-42 showed 95% copper adsorption from an initial feed/solution of 100 ppm Cu at pH 4 in contact time of 15 and 30 min, respectively. Adsorption data for both the adsorbents were fitted well to the Freundlich isotherm. Experimental results were also validated with the kinetic model, which showed that the adsorption of copper followed pseudo-second order rate expression for the both adsorbents. Overall result demonstrates that the bio-adsorbent tested has a potential applicability for metal recovery from the waste solutions/effluents of metal finishing units. In view of the requirements of commercial viability and minimal environmental damage there from, Datura root powder being an effective material for metal uptake, may prove to be a feasible adsorbent for copper recovery after the necessary scale-up studies

Treatment of industrial effluent to reclaim copper using adsorption technique

The effluent generated during metal finishing in industries contains a large amount of heavy metals, which get discharged into water bodies and create environmental pollution as well as loss of metal values. Present studies report the adsorption of copper (Cu) from the effluent using Tulsion T-42 resin. Experiments were carried out for the adsorption of Cu from the effluent of Chemical and Mechanical Polishing (CMP) industries using cationic resin Tulsion T-42 (adsorbent). To get the optimized adsorption condition for copper the studies were carried out with varying process parameters i.e., contact time, adsorbent dose, pH, etc. The result of the batch experiments shows that 95% copper was adsorbed from the effluent containing 100 ppm copper using 0.1 g Tulsion T-42 in 50 mL feed solution at pH 4.0 in a contact time of 30 min. The obtained data from Cu adsorption studies fitted well with Freundlich adsorption isotherm and followed second-order rate reaction. The 99% copper was found to be eluted from loaded adsorbent using 10% sulfuric acid in 60 min contact time. FT-IR results confirmed that a complex with an active sulphonic group of Tulsion T-42 was formed. The findings of the studies will be useful for the reclamation of copper from the wastewater of metal-finishing industries

E-waste recycling: alternative metal resources

With the advancement in living standards and economical growth, the demand and supply for electrical and electronic goods have seen a quantum jump with its fascinating techno-logical innovation and alluring features. This has resulted in tremendous and incredible increase in the sale and production of electrical and electronic equipments(EEE).The old models are replaced rapidly by the latest and advanced ones which have generated a large amount of E-wastes, commonly known as the Waste Electrical and Electronic Equipments (WEEE).Basically, any electrical and electronic appliance that has reached its end of life are categorised as WEEE