Lithium cobalt oxide from a wasted lithium ion secondary battery (LIB) is recovered by means of flotation. At first, the wasted LIB was crushed by vertical cutting mill and classified by air table and vibration screen. Referring to the crushing and separating results, wasted LIB is represented by light materials (organic separator of anode and cathode of battery), metallic materials (aluminum & copper foil, aluminum case etc.) and electrode materials (mixture of lithium cobalt oxide (LiCoO2) and graphite). Electrode materials were thermally treated in a muffle furnace at 773K, followed by flotation to separate LiCoO2 and graphite. The fact that the surface of particles was changed from hydrophobic to hydrophilic due to the removal of binder from the surface at 773K. Considering the results, 92% LiCoO2 was recovered from electrode materials, whereas the purity was higher than 93%. The optimum conditions of flotation process were as follows: 0.2 kg/t kerosene as a collector, 0.14 kg/t MIBC as a frother and 10% pulp density. The experimental results suggested that this process by using mineral processing technology, such as crushing, screening, flotation, etc., is feasible to recover LiCoO2 from the wasted LIB representing a new recycling technique.
Based on the chemistry of alinite compound, we have successfully converted a wide variety of flyashes and other mineral, industrial and municipal waste materials into a new class of hydraulic setting alinite cements. Three case studies are presented for producing good quality alinite cements from representative samples of flyash from a thermal power plant in India, tailings sands from an Indian gold processing plant and chloride rich municipal incinerator ash obtained from South Korea. The process parameters optimized include raw mix composition—represented by lime index and chloride content—clinkering temperature schedule and clinker grinding fineness.
Nickel (Ni), zinc (Zn) and phosphorus (P) found in wastewater from industrial factories were effectively removed by physicochemical adsorption using mainly natural zeolite. At first, the fine ground natural zeolite particles and aluminum ion were directly added in the solution and agitated. Subsequently, the pH of solution was adjusted from 6 to 10 while stirring. Different samples were collected from the solution at different periods of time. Each of them was analyzed by Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). Industrial wastewater has been tested. The best results were achieved while 50 mg/l of natural zeolite and 0.5 mg/l of aluminum ion were added into solution at pH 10. Referring to the results, more than 98% of Ni and Zn and more than 94% of phosphorus were removed from the wastewater.
Ethylamine(EA) was used as an additive instead of mineralizers such as NaOH and TPAOH to synthesize MCM-41 molecular sieves with high structural stability and long range order. Small angle X-ray diffraction showed that the EA/CTAB (cetyltrimethylammonium bromide) ratio was the critical factor that determines the degree of ordering in MCM-41. The samples had walls approximately 2 nm thick, which is the thickest level ever reported. Therefore, they did not lose their structure entirely even after heat treatment at 1000°C. Together with the effect of the EA/CTAB ratio, the textural mesoporosity, as confirmed from the N2 adsorption-desorption isotherm analysis, suggests the EA participates in the templating process of the mesostructure. In addition, the decrease of the lattice parameter and the pore size with increasing EA concentration implies the role of EA as co-surfactant.
A newly designed cyclone type electrolyzer was tested to recover the copper powder from the waste rinse water of Cu electroplating process. Polarization measurements were performed to investigate the electrochemical behavior of copper ions and limiting current density in waste rinse water from copper electroplating processes. Electrowinning was performed at room temperature and the electrolyte was strictly controlled to circulate with a linear velocity of more than 1 m/sec using magnetic pump. More than 99 percent of Cu ion was successfully recovered and the size of the recovered Cu powder ranges from 0.1-0.5 μm. The Cu powder mainly consisted of Cu2O and Cu. It was easily reduced to pure Cu powder.
The liquid-phase synthesis method for preparing phosphor (Y2O3: Eu) fine particles, which was expected in the application for mercury-free fluorescent lamps, was investigated. The monodispersed sols as the precursor of phosphor fine particles were first synthesized by the co-precipitation method under different conditions in the aqueous-phase. The colloidal particles of precursor sols were spherical and almost uniform. The particle sizes of the sols were under 1 μm, and the size distributions were sufficiently narrow. The metal element ratio of the sol particles could be controlled by adjusting the initial concentration of the synthesis solution. The as-prepared precursor sols were converted into well crystalline phosphor particles by heat-treatment over approximately 600°C. The phosphor particles showed emission spectra with a remarkable emission line of Eu3+ activator, and the emission intensity was sensitively influenced by the concentration of Eu3+ in the precursor solution. A morphological feature as the monodisperse of the phosphor particles remained after the heat-treatment.
Improvement of different properties of ecocement (EC), a new class of hydraulic cement by using pozzolanic materials is important for its wide applications. Present communication reports the hydration behaviour of ordinary ecocement in presence of metakaolin (MK). Ecocement and 5, 10 and 20% metakaolin containing ecocement pastes were hydrated up to 28 days at room temperature and hydration products were characterized by thermo gravimetric as well as XRD techniques. Lower amounts of Ca(OH)2 and chemically combined water (CH and CW respectively) were formed in EC hydration than those formed during the hydration of normal Portland cement (NPC). Addition of MK enhanced the rate of hydration reaction with increase formation of hydration products like C-S-H and startlingite (C2ASH8). [C: CaO, S: SiO2, A: Al2O3, H: H2O, S: SO3]
The purpose of this study is to use the waste sludges generated in steel making industries as a raw material of ordinary portland cement (OPC). In this study the characteristics of the sludges, suitable mix design of raw materials, the minerals synthesized, physical properties of clinker, effect of chlorine, and heavy metals for operations were investigated in a pilot kiln. As a result, it was found that the waste sludge mainly included CaO, SiO2, Al2O3 and Fe2O3 which are the main components of OPC and components causing operation troubles in a kiln such as MgO, SO3 and chlorine were also in the sludges. Most of the sludges were clogged in moisture content of 25∼30%. Coating in the kiln increased as the experiment was repeated. Main anions of the coated matter were SO32- and Cl-, and the content of SO32- was 15.2%, Cl-, 25, 414 ppm. Chlorine circulation behavior was simulated by the Weber model, and when the addition content of the sludge mixture was 3%, the suitable by-pass rate of chlorine was 2% in consideration of the chlorine limit value of 5, 000 ppm in a industrial cement plant. Main mineral phases, setting time and the compressive strength of cement produced were equal to those of OPC. About 50, 000 tons of clinkers were produced using the addition content of 1% and 2% in a cement plant. All the characteristics of the cement produced had no differences compared with OPC, and the circulation matter did not affect operations and cement quality.
The electrochemical behavior of platinum in dilute acidic media solutions were investigated using a rotating disc electrode system and a modified electrochemical cyclone cell at 25°C. Electrochemical polarization data showed that the limiting current density for platinum deposition was observed around −0.25 V (vs. SCE), and the diffusion coefficient of platinum estimated using Levich equation was 3.25 × 10-6cm2 s-1. The effects of several variables such as applied voltage, hydrochloric acid concentration and electrolyte flow rate were examined using a cyclone cell in order to obtain the optimum condition for electrowinning of platinum. More than 90% of the platinum in solution was recovered within an hour under the optimum conditions.
This study was performed to investigate the efficiency of hindered-settling column for recovering carbon from Korean anthracite. Laboratory scale hindered-settling equipment was set and two coal samples were prepared for tests. For each samples, washability analyses were performed, and several set of tests were conducted to evaluate the effect of two important operating variables, set point and teeter water flow rate. Also, mathematical model of continuous hindered-settling separation was developed. Modeling program was established and simulations were carried out to evaluate column performance at several operating variables, such as dispersion and teeter water flow rate.
Chlorine sources, forms and chlorine concentration of combustion materials are considered to be the most important factors influencing the formation of dioxins/furans (Dioxins) in the combustion processes. Therefore, one of the effective methods to suppress the formation of Dioxins is expected to dechlorinate from combustion materials at high temperatures. In the present work, effects of chlorine sources, forms and chloride concentration on the formation of Dioxins and effect of the dechlorination on the suppression of Dioxins formation in the combustion process have been investigated in the combustion furnace of a laboratory scale at 1073 K. The concentration of Dioxins formation is nearly proportional to the chloride content of combustion materials under the conditions of the same chlorine sources and forms, and besides, its concentration is significantly influenced by chlorine sources, i.e. organochlorine compound or inorganic chloride. Furthermore, even in the case of inorganic chloride, Dioxins of high concentration are formed under the existence of the active chlorine with high reactivity such as chlorine ion in the hydrate, made from salt and flour. On the other hand, Dioxins are hardly formed by the dechlorination from combustion gas and fly carbonaceous matters with CaO chips put in the combustion furnace.