XRF Results Research Articles

Sustainable material manufacturing from hazardous bauxite red mud in composites with clay slate waste and lime production waste

The primary purpose of this study was to experimentally validate the possibility of using hazardous red mud (RM) from bauxite ore treatment and clay slate mining wastes (SW)—scraps of slabs and polishing sludge—as the main raw components in composites with poorly burned limestone as lime production wastes (LPW) here used as a binding additive. Mixtures of these components were homogenized, hydrated, and compacted with a compressive strength of 10 MPa. The incorporation of 15–30% LPW led to axial strength values of 4.7–12.8 MPa on the 28th curing day and 10.6–23.7 MPa on the 365th day. The results of XRF, XRD, AAS, and SEM with EDS, DTA-TGA, and LAMMA analyses showed that all mechanical properties of the developed materials were enhanced due to the synthesis of new formations, mainly amorphous and partly crystalline, during the microstructural densification of the composites. The developed materials can be used as road base and airfield runways, levee cores, industrial and municipal waste dumps, building foundations, and production of tiles, bricks, and blocks. The most important contribution of this study is the convincing experimental evidence of an efficient engineering solution to the ecological problems of three types of industrial enterprise, without the use of expensive traditional market materials such as Portland cement or commercial lime, preventing the accumulation of large amounts of these wastes in industrial dumps. Furthermore, it would significantly reduce nature’s irreversible destruction by quarries of natural raw material like clay, sand, and crushed stone.

An Investigation into the Mechanical and Wear Characteristics of Hybrid Composites: Influence of Different Types and Content of Biodegradable Reinforcements

ABSTRACT This research work focuses on the wear characteristics of hybrid composites prepared using Sisal fiber (SF) /Pineapple fiber (PF) and Pineapple fly ash (PA) in various wt.%. Linear reciprocating tribometer was used for determining the Specific Wear Rate (SWR) and Coefficient of Friction (CoF) of the hybrid composites. The XRF results of PA filler showed the existence of silica (64.43%) and aluminum oxide (10.03%) in a major percentage. The hybrid fiber combination of 30-50 wt.% showed improvement in Tensile Strength (TS), Flexural Strength (FS) and Impact Strength (IS) with the filler mixing up to 5 wt.%. The Taguchi optimization (SN graph) observed the combination with PA addition of 5 wt.%, hybrid fiber addition of 30 wt.%, sliding distance and load of 1500 m, 10 N having lower SWR. Similarly for lower CoF, fly ash of 1 wt.%, fiber of 30 wt.%, sliding distance and load of 500 m and 5 N, respectively, with high SN ratio is the best combination. SEM results showed a decrease in filler content, higher load conditions, higher reinforcement causing more surface deformations in the composites.

Using inverse replica fixture technique for improving nano-finishing of hip joint implant in abrasive flow finishing process

The total hip arthroplasty (THA) is considered as one of the most successful orthopedic surgeries, through which the damaged hip joint is replaced with hip joint prosthesis. Besides, automatic nano-finishing of femoral head is of great importance in improving tribological, biological, and metallurgical properties of hip joint implants and increases the productivity of manufacturing process. In the present effort, to satisfy these requirements, a new inverse replica fixture of femoral head has been proposed in the abrasive flow finishing (AFF) process. In addition, the effect of AFF parameters including extrusion pressure, number of finishing cycles, and abrasive mesh size has been investigated on the surface roughness of the femoral head which is made of ASTM F 138 (SS 316 L). For conducting the experimental tests, a setup of AFF process is designed and fabricated. The experiments are performed according to the design of experiments and the full factorial method. Statistical analysis of the experimental data shows that the most significant parameter is the abrasive mesh size. Moreover, the surface topographic parameters of Ra, Rq, Rp, Rv, and Rt of femoral head under experimental conditions; extrusion pressure of 9 MPa, number of finishing cycles of 100, and abrasive mesh size of 1000 have improved by 91.71%, 91.21%, 81.84%, 88.46%, and 85.44%, respectively. Furthermore, SEM and AFM images of the surface texture of the femoral head before and after the AFF process demonstrate the elimination of CNC lathe traces along with achieving mirror-like surface up to the range of 20.3 nm. In addition, regarding the XRF results, no considerable variation in the chemical composition of femoral head before and after the AFF process is observed.

Synthesis of a novel magnetic nano-zeolite and its application as an efficient heavy metal adsorbent

A novel magnetic nano-zeolite (MNZ@MS) is successfully synthesized, characterized and applied to adsorp heavy metals from solution. In the synthesis of MNZ@MS, the fly ash magnetic sphere (MS) and [C18H37 (CH3)2-N+-(CH2)3 -N+-(CH3)2C18H37] Cl2 is used as carrier and directing agent, respectively. The characterization results of XRD, XRF, XPS and SEM demonstrate that the nano-scale (200–600 nm) Linde F(K) zeolite completely wraps the magnetic spherical fly ash particle, and the saturation magnetization value of MNZ@MS is around 17.7 emu g−1. MNZ@MS exhibits a favorable and efficient adsorption performances on heavy metals, and the maximum adsorption capacity of Cu, Cd and Pb on MNZ@MS is 59.9 mg g−1, 188 .6 mg g−1 and 909.1 mg g−1, respectively. The higher pH value in solution is more conducive to the adsorption process of heavy metals on MNZ@MS. The adsorption is a fast process, well represented by the pseudo-second-order model. Concerning the equilibrium behavior, Langmuir isotherm model are more suitable for describing the adsorption. Furthermore, in competitive adsorption system, the adsorption process of Pb is the most difficult to be interfered, and the order of adsorption advantage is Pb>Cu>Cd. MNZ@MS may be applied as a low-cost and efficient magnetic adsorbent for wastewater treatment to remove heavy metals.

Efficiencies and mechanisms of steel slag with ferric oxides for removing phosphate from wastewater using a column filter system.

The current study aimed to investigate the efficiencies and mechanisms of slag filter media for removing phosphorus from synthetic wastewater. The steel slag with high ferric oxides (Fe2O3) was subjected for the electric arc furnace (EAF) and selected as the filter media (HFe). The chemical characteristics of HFe were determined using pH, point of zero charge (PZC) and XRF. The phosphorus removal efficiency was studied in a designed vertical steel slag column rock filters in unaerated HFe (UEF) and aerated HFe (AEF) system. The microstructure of HFe was analyzed by FTIR, XRD and SEM-EDX analysis. The results of XRF revealed that ferric oxide (Fe2O3) ranged from 26.1 to 38.2%. PZC for Filter HFe was recorded at pH 10.55 ± 0.27. The highest efficiencies were recorded by UEF and AEF systems at pH 3 and pH 5 (89.97 ± 4.02% and 79.95 ± 6.25% at pH 3 and 72.97 ± 8.38% and 66.00 ± 12.85% at pH 5 for UEF and AEF, respectively). These findings indicated that AEF exhibiting higher removal than UEF systems might be due to presence high Fe concentration in AEF which play important role in the phosphorus removal. The main elements available on the surface of HFe included carbon, oxygen, iron, calcium, magnesium, silicon, platinum, sulphur, manganese, titanium and aluminium. The XRD analysis indicated that the precipitation of orthophosphate as calcium and iron-phosphates was the removal mechanism as confirmed using FT-IR analysis. These findings demonstrated the efficiency of HFe in removing of phosphorus from wastewater.

Reinforce of hydrotalcite-like loaded TiO2 composite material prepared by Ti-bearing blast furnace slag for photo-degradation of tetracycline

In this study, a composite material of hydrotalcite-like loaded TiO2 (TiO2@Mg-Al LDH) was prepared from Ti-bearing blast furnace slag (Ti-BFS) and used for photo-catalytic degradation of tetracycline (TC) in aqueous solution. The results of SEM, XRD, XRF, FT-IR, BET and UV-Vis DRS showed that photocatalytic TiO2@Mg-Al LDH was layered double hydroxide loading TiO2 structure and doped with metal elements, which could effectively induce the excitation wavelength of TiO2 to extend from UV to visible region. At the initial TC of 20?mg/L, the removal rate of TC and TOC were more than 90% and 72% within 120?min using UV in combination with TiO2@Mg-Al LDH. The radical quenching tests and EPR analysis indicated that TC degradation and mineralization were attributed to production of abundant OH• radicals, •O2- and h+ under UV conditions, which performed different proportion of removal, compared with adsorption experiment under non-light irradiation. Qualitative analysis of the by-products showed the aromatic ring of TC was opened, which effectively reduced the virulence of by-products. It indicated that the synergistic effect of hydrotalcite-like structure and photocatalysis could achieve efficient photodegradation of TC by TiO2. TiO2@Mg-Al LDH synthetized by high Ti-bearing blast furnace slag presented a good prospect of removing trace organic pollutants under synergistic effect of adsorption and UV photo-catalytic.

Synthesis of precipitated silica from bagasse ash as reinforcing filler in rubber

Bagasse ash as waste material from the sugarcane industry is causing disposal problems. This paper study on the use of silica from bagasse ash as reinforcing filler in rubber. Precipitated silica was obtained from bagasse ash through a sol precipitation method. Process parameters such as time of addition of secondary sodium silicate, pH and temperature, were studied. The synthesized silica was characterized by XRF, XRD, and PSA. XRF and XRD test results showed that the precipitated silica contained 4.9% of alumina and had an amorphous structure, respectively. PSA result showed that the synthesized precipitated silica and a commercial reinforcing filler had a comparable aggregate/agglomerate size distribution after 10 minutes sonication. The yield of silica recovered from bagasse ash was found to vary between 41.7% and 58.2%.

Provenance identification of ancient pottery from Hachijojima Island, part of Izu Islands (Tokyo, Japan), using X‐ray fluorescence spectrometry

AbstractA total of 47 pottery fragments were unearthed in Hachijojima Island, part of the Izu Islands (Tokyo, Japan). Among these samples, 36 found in the Kurawa site had designs resembling pottery dating back to the Jomon period (14,000–300 BC) distributed throughout Japan's main island, Honshu; five samples from the Jomon period found in the Yubama site were “undesigned”; the rest, found in the Yaene site, were undesigned Haji pottery samples dating back to the beginning of the late Kofun period (490–549 AD). X‐ray fluorescence spectrometry (XRF) was used to determine the chemical composition (in terms of 10 major oxides and 12 minor elements) of the samples to identify their provenance, that is, local versus nonlocal. For this purpose, a portion of each pottery fragment was processed to obtain a glass bead specimen. The pottery samples were classified by multivariate statistical approaches, including principal component analysis and cluster analysis, on the basis of their chemical composition. Additionally, the XRF results were compared to geochemical data from Hachijojima Island using scatter diagrams. The data thus collected allowed the provenance of the pottery samples to be inferred. In particular, the 36 samples from the Kurawa site were concluded to have been brought to Hachijojima Island from Honshu in prehistoric times, whereas the other samples were concluded to have been manufactured locally.

Recovery of rutile from Ti-Bearing blast furnace slag through phase transformation and super-gravity separation for dielectric material

High-purity rutile (TiO2) possessing favorable dielectric properties was sustainably recovered from Ti-bearing blast furnace slag through phase transformation and super-gravity separation in this study. Firstly, the phase transformation behavior of Ti was studied, the favorable conditions for transformation from perovskite to rutile were determined, and the Ti elements were efficiently enriched into rutile in the Ti-bearing blast furnace slag. Subsequently, the condition for solid and liquid phases of rutile and slag in coexistence was acquired by high-temperature CSLM, the rutile was effectively recovered from the Ti-bearing blast furnace slag through super-gravity separation, and its high purity was verified by the results of XRD, SEM-EDS, XRF, EPMA and Raman. Moreover, the rutile ceramic was prepared, and its dielectric properties were investigated, the dielectric constant was up to around 200, and the dielectric loss was as low as 0.0047 at about 900 Hz. The excellent frequency stability, high dielectric constant and low dielectric loss of the rutile recovered from Ti-bearing blast furnace slag reflect its favorable energy storage capability for dielectric material.

Chemical, mineralogical and petrological characterization of Gyaza iron ore deposit, Katsina State, Nigeria

Chemical, mineralogical and petrological characterization of Gyaza iron ore deposit, Katsina State, Nigeria was carried out. The ore sample was sourced from Gyaza village, Kankiya Local Government Areas of Katsina State and comminuted using laboratory jaw crusher and pulverizing machines respectively. The comminuted sample was analyzed using XRF, XRD, SEM and OPM. The XRF result revealed that the ore contained 0.17%P, 0.02%K, 0.23%Ca, 0.11%Mn, 36.17%Fe, 0.08%Ba, 0.18%Mg, 1.10%Al and 17.21%Si. The XRD result revealed that the complex mineral phases of the ore are Aluminum-Silicate-Hydroxide-Hydrate (Al2Si2O5(OH)4.2H2O), Chrysotile (Mg3[Si2-xO5](OH)4-4x), Magnesium-Aluminum-Silicate-Hydroxide-Hydrate ((Mg,Al)9 (Si,Al)8O20 (OH)10.4H2O), Sodium-Calcium-Magnesium-Aluminum-Silicate (NaCa2Mg5AlSi7O22(OH)2), Sodium-Iron-Silicate-hydroxide ((Na,Ca) 2 (Fe,Mn)Fe2 (Si,Al)8O22 (OH)), Orthoclase (KAlSi3O8) and Sodium-Calcium-Iron-Aluminum-Silicate-Hydrate (NaCa2Fe4AlSi6Al2O22(OH)2). And the single mineral phases are Quartz (SiO2), Hematite (Fe2O3) and Goethite (Fe2O3.H2O) which are also the major minerals phases. The SEM and petrological results revealed that the ore matrix is an assemblage of inter-layered different minerals crystals with different shapes, sizes and angles of orientations and separated by grain boundaries. http://dx.doi.org/10.4314/njt.v38i3.17

Enhanced hexavalent chromium (Cr(VI)) removal from aqueous solution by Fe–Mn oxide-modified cattail biochar: adsorption characteristics and mechanism

ABSTRACTIn the study, a novel Fe–Mn oxide-modified cattail biochar was synthesised and Cr(VI) adsorption on Fe–Mn oxide-modified biochar in water was investigated. XRF, XRD and FTIR results indicated that Fe and Mn were successfully loaded on the surface of Fe–Mn oxide-modified biochar. Batched experiments showed that Cr(VI) adsorption on Fe–Mn oxide-modified biochar fitted well with the pseudo-second-order kinetics model. The Freundlich isotherm adsorption model could better describe the isothermal adsorption process of Cr(VI) onto Fe–Mn oxide-modified biochar. The maximum saturated adsorption capacity data Qm of Fe–Mn oxide-modified biochar at 20°C, 30°C, and 40°C were respectively 46.43, 52.12, and 59.81 mg·g−1. The lower pH contributed to the adsorption of Cr(VI) onto Fe–Mn oxide-modified biochar. The effects of coexisting anions on the Cr(VI) removal efficiency were insignificant. Leaching experiments showed that the leakage risk of Mn2+ during the adsorption process was negligible. The adsorption mechanisms of Cr(VI) onto Fe–Mn oxide-modified biochar mainly involve electrostatic attraction, ligand exchange and complexation. All the results suggested that Fe–Mn oxide-modified biochars could serve as promising adsorbents for Cr(VI) pollution treatment.

Kaunas Castle from Another Perspective: the Chemical Composition of Iron Construction Elements

The chemical composition of iron construction elements is not usually a topic of interest in Medieval archaeology. This article focuses attention on the chemical composition of iron elements such as nails. For compositional analysis, the XRF method was used. A comparison was made between XRF results and physical measurements. The aim of this article was to identify the amount of iron in metal elements that were possibly used in constructing castles, and to find a connection between the chemical composition of objects and their physical measurements.

Synthesis and characterization of Fe2O3 doped ZnO supported on clinoptilolite for photocatalytic degradation of metronidazole

ABSTRACT ZnO/Fe2O3/Clinoptilolite photocatalyst was synthesized through sol–gel method. The photocatalyst was characterized by XRD, XRF, EDX, FE-SEM, FT-IR, BET and UV–VIS DRS analyses. According to the XRD, FT-IR, and EDX results, the presence of ZnO and Fe2O3 was confirmed on the clinoptilolite surface. Based on the XRF results, the molar ratio of Fe3+/ZnO in the photocatalyst was obtained as 0.06. The FE-SEM results confirmed stabilization of ZnO/Fe2O3 on the clinoptilolite surface. Based on the BET results, the surface area and pore volume for the photocatalyst were obtained as 291.35 m2/g and 0.23 cm3/g, respectively. According to the UV–VIS DRS results, the band gap energy of the photocatalyst was measured as 3.38 eV. The performance of the synthesized photocatalyst in degrading metronidazole from contaminated water, as one of the most widely used antibiotics in pharmaceutical industries, was evaluated by response surface methodology. Operational factors including pH (4–10), metronidazole concentration (1–100 mg/l), irradiation time (45–180 min), photocatalyst concentration (0.5–2 g/l), and H2O2 concentration (25–100 mg/l) were investigated. The optimal values of the factors in degrading 99% of the contaminant were as follows: irradiation time = 90 min, photocatalyst concentration = 1 g/l, pH = 10, H2O2 concentration = 40 mg/l, and MNZ concentration = 60 mg/l.

Hexavalent chromium removal from aqueous solution by adsorption on modified zeolites coated with Mg-layered double hydroxides.

In this study, MgAl-LDHs and MgFe-LDHs were synthesized via co-precipitation method and in situ coated on pre-washed zeolites through dipping process in beaker. The obtained modified zeolites and original zeolites were utilized as substrates of constructed rapid infiltration systems (CRIS) to remove hexavalent chromium (Cr(VI)) in wastewater. Micro-morphology features and chemical composition of zeolites before and after modification were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence spectrometer (XRF). The SEM, XRD, and XRF results demonstrated the feasibility of LDHs coated on the surface of the original zeolites. Purification experiments in simulated CRIS showed that the Cr(VI) removal rates of zeolites/MgAl-LDHs increased by 110.03% on average every concentration (0.5-16 mg L-1) compared with the original zeolites under 24-h HRT. The adsorption capacity of zeolites/MgAl-LDHs reached 66.98 mg kg-1 at 32 mg L-1 initial Cr(VI) concentration, which is nearly twice that of the original zeolites (33.24 mg kg-1) and 1.5 times higher than that of zeolites/MgFe-LDHs (42.01 mg kg-1). Isothermal adsorption tests showed that the Freundlich isotherm equations gave better fitting to the adsorption process. And zeolites/MgAl-LDHs showed a best fit with pseudo-second-order model which meant that the adsorption of Cr(VI) by zeolites/MgAl-LDHs was dominated by chemisorption. Thermodynamic parameters showed that the process of adsorption for the three substrates was spontaneous and endothermic intrinsically. Zeolites/MgAl-LDHs also displayed nearly 60% desorption rate with low concentration eluent (0.01 mol L-1 NaCl). Therefore, zeolites/MgAl-LDHs were chosen out as an optimal substrate for removing Cr(VI) from wastewater in CRIS. Graphical Abstract.

Investigation of the compressibility and sinterabilty of AZ91 powder production and particle production by gas atomisation method

Abstract This study intends to determine the pressability and sinterability of AZ91 powder production by gas atomisation method and that of the produced powder for partial production. Therefore, first, a gas atomisation unit has been designed and manufactured in the laboratories of the Karabuk University, Department of Manufacturing Engineering. Atomised powder production has been achieved at a temperature of 795 °C, with nozzle diameters of 2 and 4 mm and four different gas pressures (5, 15, 25, 35 bars). Argon gas has been used for atomisation and as a protective gas atmosphere. Scanning electron microscope (SEM) is used to determine the shape of the produced AZ91 powder, and a laser particle size analyzer is used to analyze the powder size. Additionally, a microhardness (HV0.025) measurement has been conducted to determine the hardness of the produced powders. To achieve a homogeneous distribution, the produced powders are mixed in a three-dimensional moving turbulator for 30 min. Mixed powders have been pressed at 300, 400, 500 and 600 MPa and have been sintered at 500 °C, 550 °C and 600 °C. Additionally, the density values have been determined before and after sintering of the materials. SEM images have been obtained from the fractured surfaces of the samples before and after sintering. XRD and EDX analyses have been performed to determine the chemical composition. Further, microhardness (HV0.5) is obtained from the pressure surfaces of the samples to determine the effects of the pressing pressure and the sintering temperature on the hardness. As a result of the experimental studies, it has been observed that the powder size decreases with the increase in gas pressure and that the powder shape generally changes from ligament and complex shape to droplet and spherical shape. From the XRD, XRF and EDX results, it has been determined that the structure comprises an α phase (Mg main matrix) and Mg17Al12 interphase, which is β phase, and very small amounts of MgO have been observed. The hardness of the produced powders increased based on the increase in gas pressure. The densities of the samples increased with both increasing pressing pressure and sintering temperature. It has been observed from the fractured surface SEM images that the number of pores formed in the samples decrease with an increase in the pressing pressure. It has been determined that the post-sintering structure exhibits a typical dendritic structure. In addition to the α-Mg matrix phase, β (Mg17Al12) intermetallic and α + β eutectic were formed in the structure. The microhardness values of the samples decreased depending on the sintering temperature; the highest hardness value was measured as 64,02 HV0.5 at a pressing pressure of 300 MPa and a sintering temperature of 500 °C, whereas the lowest hardness value was measured as 54,86 HV0.5 at a pressing pressure of 600 MPa and a sintering temperature of 600 °C.

Investigating the potential reactivity of fly ash for geopolymerization

This study investigated potential reactivity of fly ash for geopolymerization. A combined dissolution of fly ash in NaOH in conjunction with HCl extraction of fly ash-NaOH residue is proposed in this study to more accurately estimate the total reactive content and reactive Si/Al ratio of fly ash. Results show that the total reactive content of fly ash used in the current study is about 68.80%, similar to the amorphous content (66.28%) obtained using quantitative XRD and XRF. The values of reactive Si/Al ratios are between 2.65 and 2.98 depending on the duration of dissolution. The reactive Si/Al values differ significantly from the total Si/Al ratio (1.63) calculated using XRF results and also differ from the vitreous Si/Al ratio (3.75) calculated using combined XRF and XRD results. The results suggest that total or vitreous Si/Al ratio should not be used for mix proportioning of fly ash geopolymers as is generally used for metakaolin-based geopolymers. Instead, the reactive Si/Al ratio determined based on the current study should be used for fly ash geopolymer mix design.

The dry ashing - AAS method and the microwave digestion -ICP-MS method for determination of lead in plastic packaging bag

A pink plastic packaging bag sample from a enterprise was preliminarily screened via X-ray fluorescence spectroscopy method (XRF), it was found that the lead content exceeded the limit of relevant national standards. Subsequently, the total lead content in the packaging bag was determined via atomic absorption spectrophotometry pretreated by dry ashing method (DA-AAS) and inductively coupled plasma–mass spectrometry with microwave digestion method (MD-ICP-MS), respectively. The working curve equations were obtained by linear least squares method with the calculated linear correlation coefficients r above 0.9998 and the relative standard deviation (RSD) of the determination results from 1.0% to 6.2%, which was in good agreement with the result of XRF.

Effect of erbium nanoparticles on structural and spectroscopic properties of bio-silica borotellurite glasses containing silver oxide

Er3+ NPs doped bio-silica borotellurite glasses containing silver oxide were prepared using melt quenching techniques. The silica used was extracted from rice husk by acid leaching process. Optical absorption and photoluminescence properties of the glass samples were studied. The samples were confirmed to be amorphous in nature from the XRD results. The FTIR results reveal the existing functional groups in the glass structure. XRF result shows that 98.6% silica was obtained from the rice husk. The optical absorption spectra revealed that fundamental absorption edge shifts to longer wavelength as the content of erbium NPs increases. The value of band gap had been calculated and shown to be increased with an increase content of erbium NPs. The Urbach energy was shown to be linearly decreased with an increase in content of erbium NPs oxides. The introduction of silver oxides modifies the optical properties of the glass. The emission cross-section (δe) and gain bandwidth (FWHM ×δe) for 4I13/2→4I15/2 transition were calculated from the McCumber theory. The photoluminescence spectra revealed three emission bands corresponding to 4H11/2-4I15/2 (470 nm), 4S3/2-4I15/2 (561 nm) and 4F9/2→4I15/2 (758 nm) transitions assigned to green and red emissions respectively. The results suggest that these glasses might be used as a promising candidate as well as gain media for solid state lasers.

Recovery of metals in waste printed circuit boards by flotation technology with soap collector prepared by waste oil through saponification

Recycling metal from waste printed circuit boards (WPCBs) through green flotation technology has been concerned in this paper. For the sake of environmentally friendly of flotation process, a renewable collector was prepared from waste oil by saponification reaction. The collector composition was analyzed by GC-MS, and results show that the main compositions are n-Hexadecanoic acid, oleic acid and octadecanoic acid. XRD and XRF results show that copper is the main valuable element for recovery. Effects of collector dosage and pH on flotation behavior were analyzed. In addition, the feasibility of improving copper recovery by multiple sorting test processes was also verified. Flotation results show that the concentrate yield and metal recovery decreases with the increase of collector dosage, accompanied by the increase of copper grade. When the dosage of collector is 3 kg/t, concentrate with 22% yield, 66% copper grade, and 47% copper recovery is obtained. Furthermore, concentrate yield and metal recovery rate first decrease and then increase with the increase of pH, while copper content first increase and then decrease. The suitable pH of the separation process is neutral environment (pH = 6–8). The study provides an alternative process for the recovery of metals in WPCBs.

Application of Avaatech X-ray fluorescence core-scanning in Sr/Ca analysis of speleothems

Application of X-ray fluorescence core-scanning (XRF-CS) on both marine and lake sediments has achieved remarkable results. However, its application has not been widely extended to the research on speleothems. In this study, we measure the Sr abundance and the Sr/Ca ratios of three stalagmites (two aragonite stalagmites, one calcite stalagmite) using the state-of-the-art fourth-generation Avaatech high-resolution XRF core scanner. Through comparisons among different scan paths and among different scan resolutions, as well as comparisons with inductively coupled plasma optical emission spectrometer (ICP-OES), Itrax XRF, and Artax XRF results, we confirm that the Avaatech XRF core scanner could precisely, quickly, and non-destructively analyze the high-resolution Sr abundance of speleothems. Furthermore, we combine the stalagmite δ18O records to explore the paleoclimatic significance of the measured stalagmite Sr/Ca.