Jun Yi Wu

Resource recovery of organic sludge as refuse derived fuel by fry-drying process

The organic sludge and waste oil were collected from the industries of thin film transistor liquid crystal display and the recycled cooking oil. The mixing ratio of waste cooking oil and organic sludge, fry-drying temperatures, fry-drying time, and the characteristics of the organic sludge pellet grain were investigated. After the fry-drying process, the moisture content of the organic sludge pellet grain was lower than 5% within 25 min and waste cooking oil was absorbed on the dry solid. The fry-drying organic sludge pellet grain was easy to handle and odor free. Additionally, it had a higher calorific value than the derived fuel standards and could be processed into organic sludge derived fuels. Thus, the granulation and fry-drying processes of organic sludge with waste cooking oil not only improves the calorific value of organic sludge and becomes more valuable for energy recovery, but also achieves waste material disposal and cost reduction.

Selective leaching process for the recovery of copper and zinc oxide from copper-containing dust

The purpose of this study was to develop a resource recovery procedure for recovering copper and zinc from dust produced by copper smelting furnaces during the manufacturing of copper-alloy wires. The concentrations of copper in copper-containing dust do not meet the regulation standards defined by the Taiwan Environmental Protection Administration; therefore, such waste is classified as hazardous. In this study, the percentages of zinc and copper in the dust samples were approximately 38.4% and 2.6%, respectively. To reduce environmental damage and recover metal resources for industrial reuse, acid leaching was used to recover metals from these inorganic wastes. In the first stage, 2 N of sulphuric acid was used to leach the dust, with pH values controlled at 2.0–3.0, and a solid-to-liquid ratio of 1:10. The results indicated that zinc extraction efficiency was higher than 95%. A selective acid leaching process was then used to recover the copper content of the residue after filtration. In the second stage, an additional 1 N of sulphuric acid was added to the suspension in the selective leaching process, and the pH value was controlled at 1.5–2.0. The reagent sodium hydroxide (2 N) was used as leachate at a pH greater than 7. A zinc hydroxide compound formed during the process and was recovered after drying. The yields for zinc and copper were 86.9–93.5% and 97.0–98.9%, respectively.

Treatment of high copper-containing wastewater by producing magnetic material

AbstractThe purpose of this study is to provide a materialization method for high copper-containing wastewater and compare it with conventional chemical precipitation process and ferrite process. In the first stage of mineralization, the copper-containing wastewater was added into a tank with NaOH solution followed by the addition of Fe3+ ion and heated to 70°C. The molar ratio between Fe3+ and divalent metal ions () was given and the pH value of solution was controlled in the strong alkaline range (11.0–11.5). In the inverse mixing method, the whole precipitation process was carried out in the strong alkaline solution, which resulted in the simultaneous precipitation of Fe3+, Cu2+, Ni2+ and Zn2+ ions. The first reaction was complete when the ORP remained constant. Finally, the formation of the magnetic ferrite, Fe2+ ion was added into the solution accompanied by heating and aeration. The magnetic separation could be then used for solid–liquid separation. Therefore, these results reveal that not only the ...

Recovery of cupric oxide from copper-containing wastewater sludge by acid leaching and ammonia purification process

Abstract The purpose of this study is to provide an efficient, simple, and economical method for the recovery of copper and removal of oil residue from copper-containing wastewater sludge using acid leaching and ammonia purification. In the first stage, sulfuric acid and hydrogen peroxide were used to leach a homogeneous suspension. The copper extraction percentage exceeded 90% in 30 min and oil residue was removed from the sludge. In the second stage, ammonia/ammonium carbonate media were used to purify the sulfuric acid leachate by forming an ammine complex. Through this process, ammonium hydroxide was recovered using an evaporating device and copper hydroxide was transformed into cupric oxide. The purity of copper in the oxide compound reached 98.26%. The economic evaluation of this process for a capacity of six tons of copper-containing wastewater sludge per day is discussed. For an initial capital investment of NT

Resource reuse of spent pickle acid by mineralization process

3.2 million with annual operating and maintenance costs of about NT

Discussion of a Treatment Technique for Spent Picking Solution Recycling

3.13 million, the c...

Integrated technology in sequential treatment of organics and heavy metal ions wastewater

AbstractThe spent pickle acid was collected from metal surface treatment factory. The pH of spent pickle acid was lower than 1.0, and the total concentration of ferrous ion was 186 g/L. Firstly, the lower activity of metal in the spent pickle acid solution was displaced by cementation process (pre-treatment). After cementation scraped iron, the coagulant agent (poly aluminum chloride (PAC)) was added to the solution. Then, the pH of the solution was adjusted to 4.5 by ammonia to remove SiO2, P, and other impurities. Finally, the mineralization process was proceeded at pH 4.0 and 60°C with H2O2. X-ray diffraction (XRD) analysis shows that the mainly crystalline phase of the mineral product was γ-FeOOH. The high purity of Fe2O3 has been obtained by calcination from mineral product. Additionally, the economic evaluation results also show that the mineralization process was economic feasible. Therefore, this method could be applied to the metal surface treatment industry and printed circuit board manufacturin...

A study of copper recovery from copper-contaminated sludge with ferrite and selective leaching processes

Pickling is a necessary process in many metal processing industries, such as wire rod, iron and steel sheet plate, and tubing processing industries, screw and nut manufacturing and processing industries, corrosion resistant plate processing industries, and paint industry. Pickling is used to remove black rust, oxides, and other contaminants from metal surfaces in order to improve processing quality. Hydrochloric acid is often used in the pickling process. As the acid concentration decreases gradually during the process, while metal (Fe and Zn) concentrations increase gradually, when the residual concentration of hydrochloric acid in the spent pickle liquor decreases to about 3%, or the specific gravity of spent pickle liquor is greater than 1.3 (iron ion concentration is greater than 100g/L), the aged pickle liquor must be discharged and fresh pickling solution is prepared. In the wire rod industry in Taiwan, the pickling process results in highly corrosive spent pickle liquor. Although there have been multiple resource processing schemes developed, including spray roasting process, fluidized bed roasting process, and sulfuric acid displacement process, it is limited to various factors, such as the treatment capacity, initial cost, operating cost, selling prices, purity of recycled products, and market scale. This study reviewed related patented processing modes in literature, and considered the reclamation cost of waste pickling solution (SPS). The proposed technique adopts wet-process metallurgy, combined with diffusion dialysis, for reclamation of SPS and mineralization crystallization of heavy metal of residue iron. The mineralization crystallization treatment produces high-purity recycled products of ferrite and goethite processes. SPS is reclaimed, and the ferric heavy metal recycling meets the economic benefit of an actual plant. The research site of this study produces 12 tons of SPS per day, which is about 300 tons monthly, and about 3,600 tons annually, with the removal cost of 7.2 million NTD annually. If the proposed treatment system is adopted, the costs of fresh hydrochloric acid, removal, and the traditional neutral agent treatment and subsequent landfill could be greatly reduced, thus effectively reducing the environmental load. In comparison to other recycling treatment techniques, the main advantage of the proposed technique is that the treatment capacity depends on the amount of SPS, the energy consumption is relatively low, the treatment scheme is simple, the operating and maintenance costs are low, and the mineralization can produce magnetic ferrite and iron oxide recycled products with high purity.