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Flower-like ZnO microstructures were successfully produced using a hydrothermal method employing ZnSO4/(NH4)2SO4 as a raw material. The effect of the operating parameters of the hydrothermal temperature, OH−/Zn2+ molar ratio, time, and amount of dispersant on the phase structure and micromorphology of the ZnO particles were investigated. The synthesis conditions of the flower-like ZnO microstructures were: hydrothermal temperature of 160°C, OH−/Zn2+ molar ratio of 5:1, reaction time of 4 h, and 4 mL of dispersant. The flower-like ZnO microstructures were comprised of hexagon-shaped ZnO rods arranged in a radiatively. Degradation experiments of Rhodamine B with the flower-like ZnO microstructures demonstrated a degradation efficiency of 97.6% after 4 h of exposure to sunshine, indicating excellent photocatalytic capacity. The growth mechanism of the flower-like ZnO microstructures was presented.

Spherical flower-like Mg(OH)2 was successfully synthesized under conditions of Mg2+ concentration of 2 mol·L−1, molar ratio of Mg2+/NH4OH of 1:0.5, temperature of 120 °C and time of 1 h using MgSO4 solution as raw material obtained from waste magnesite through several procedures. Spherical Mg(OH)2 exhibits flower-like structure composed of lamellar crystals. The immobilization ability of spherical flower-like Mg(OH)2 for Cu2+, Zn2+ and Pb2+ obtained at variable dosage and ion concentrations shows it displays an excellent immobilization performance for Cu2+, Zn2+ and Pb2+. 50 mL solution with ion concentrations of 200 mg·L−1 could be almost completely immobilized by 200, 250 and 60 mg Mg(OH)2 within 6 min, and the immobilization efficiencies were 97.55%, 99.99% and 91.56%, respectively. Langmuir model well describes the immobilization process, involving chemisorption emphasized as monolayer.

An improved method of (NH4)2SO4 roasting followed by water leaching to utilize zinc oxidized ores was studied. The operating parameters were obtained by investigating the effects of the molar ratio of (NH4)2SO4 to zinc, roasting temperature, and holding time on zinc extraction. The roasting process followed the chemical reaction control mechanism with the apparent activation energy value of 41.74 kJ·mol−1. The transformation of mineral phases in roasting was identified by X-ray diffraction analysis combined with thermogravimetry-differential thermal analysis curves. The water leaching conditions, including the leaching temperature, leaching time, stirring velocity, and liquid-to-solid ratio, were discussed, and the leaching kinetics was studied. The reaction rate was obtained under outer diffusion without product layer control; the values of the apparent activation energy for two stages were 4.12 and 8.19 kJ·mol−1. The maximum zinc extraction ratio reached 96% while the efficiency of iron extraction was approximately 32% under appropriate conditions. This work offers an effective method for the comprehensive use of zinc oxidized ores.

NH4HCO3 conversion followed by HCl leaching was performed and proven to be effective in extracting Pb and Sr from zinc extracted residual. The mechanism and operating conditions of NH4HCO3 conversion, including molar ratio of NH4HCO3 to zinc extracted residual, NH4HCO3 concentration, conversion temperature, conversion time, and stirring velocity, were discussed, and operating conditions were optimized by the orthogonal test. Experimental results indicate that NH4HCO3 conversion at temperatures ranging from 25 to 85°C follows the shrinking unreacted core model and is controlled by inner diffusion through the product layer. The extraction ratios of Pb and Sr under optimized conditions reached 85.15% and 87.08%, respectively. Moreover, the apparent activation energies of Pb and Sr were 13.85 and 13.67 kJ·mol−1, respectively.

Employing zinc sulfate solution obtained from zinc oxide ore as raw material, sodium hydroxide as precipitant and PEG20000 as dispersant, ultrafine ZnO powders with different morphologies were successfully synthesized through hydrothermal method. The influences of the dosage of PEG20000 solution, molar ratio of OH−/Zn2+, reaction temperature, reaction time and Zn2+ concentration on the structures and morphologies of the ZnO powders were discussed in detail. The reaction conditions of synthesizing ZnO powders with flower-like structure were obtained as below: dosage of PEG20000 with 10% mass fraction 5 mL, molar ratio of OH− to Zn2+ 5, reaction temperature 150 °C, reaction time 8 h at Zn2+ concentration 1 mol L−1. The growth mechanism of ZnO particles with different morphologies was proposed. The ZnO powder with flower-like structure are composed of multiple micro-rods with hexagon morphology and has good photocatalytic degradation ability to degrade RhB. 20 mL RhB solution with 15 mg L−1 could be completely degraded over flower-like ZnO powder 300 mg within 3 h.

Conventional reduction treatment methods for nickel slag show drawbacks such as high energy cost, heavy material burden or secondary pollution. Thus, a novel environmentally friendly reduction treatment method for high-silicon wastes, especially nickel slag, is proposed in this paper. The main characteristic is to lower the alkali–ore ratio (mass ratio of NaOH to ore) through introducing a high-speed premixing procedure before roasting. Optimal process parameters have been found experimentally, i.e., a roasting temperature of 823 K, alkali–ore ratio of 1.6:1, and roasting time of 30 min. The desilication ratio reached to 91.3 wt.%. Compared with previous NaOH roasting processes with stirring, the NaOH consumption is down by 60%, which greatly reduces the material burden. Through carbonation decomposition of the Na2SiO3 solution generated in the NaOH roasting, amorphous silica is recycled as the final product. The proposed method is expected to be a promising method for industrial reduction treatment of nickel slag.

ZnO@SiO2 composite with flower-like structure was successfully prepared with molar ratio of ZnO/SiO2 = 1:1 based on the optimized synthesizing parameters of spherical SiO2 and flower-like ZnO. SiO2 particles were coated on the flower-like ZnO to form a homogeneous film through the multidimensional polycondensation of Si(OH)4. The photocatalytic degradation ability of ZnO@SiO2 composite for rhodamine B (RhB) obtained at different ZnO/SiO2 molar ratio and the comparison to that of flower-like ZnO showed that ZnO@SiO2 composite with ZnO/SiO2 molar ratio of 1:1 displayed a relatively good photocatalytic degradation ability to degrade RhB, but it was weaker than that of flower-like ZnO. Twenty millilitres of RhB solution at a concentration of 15 mg·L−1 could be completely degraded by 300 mg flower-like ZnO powder within 3 h, while the degrading efficiency was only 82.5% by 300 mg ZnO@SiO2 composite. But ZnO@SiO2 composite showed a better photocatalytic activity than flower-like ZnO at a lower pH value of 4.5.

High iron content is one of the challenges in utilizing the refractory bauxites in China. An improved method for treating the high-iron bauxite by roasting with (NH4)2SO4 was proposed, which offers a possible alternative method for utilizing the high-iron bauxite. The influences of the roasting time, roasting temperature, material ratio, and ore particle size on the extraction ratios of Fe and Al were studied, and the orthogonal test was used to optimize the reaction conditions. The optimized reaction conditions were proposed as follows: roasting temperature of 450 °C, roasting time of 120 min, material ratio of (NH4)2SO4 to ore of 2.5:1.0, and ore particle size below 80 μm. The roasting mechanism and kinetic parameters including the apparent activation energy and reaction rate constant were investigated. The results showed that the control step of the roasting process was the internal diffusion on the product layer and the apparent activation energy was 19.22 kJ mol−1 in the reaction temperature range. The kinetic equation was obtained finally.

The reaction kinetics of roasting zinc silicate using NaOH was investigated. The orthogonal test was employed to optimize the reaction conditions and the optimized reaction conditions were as follows: molar ratio of NaOH to Zn2SiO4 of 16:1, reaction temperature of 550 °C, and reaction time of 2.5 h. In order to ascertain the phases transformation and reaction processes of zinc oxide and silica, the XRD phase analysis was used to analyze the phases of these specimens roasted at different temperatures. The final phases of the specimen roasted at 600 °C were Na2ZnO2, Na4SiO4, Na2ZnSiO4 and NaOH. The reaction kinetic equation of roasting was determined by the shrinking unreacted core model. Aiming to investigate the reaction mechanism, two control models of reaction rate were applied: chemical reaction at the particle surface and diffusion through the product layer. The results indicated that the diffusion through the product layer model described the reaction process well. The apparent activation energy of the roasting was 19.77 kJ/mol.

The orthogonal test was used to optimize the reaction conditions of roasting zinc oxide ore with NaOH aiming to comprehensively utilize zinc oxide ore. The optimized reaction conditions were molar ratio of NaOH to zinc oxide ore 6:1, roasting temperature 450 °C, holding time 150 min. The molar ratio of NaOH to zinc oxide ore was the most predominant factor affecting the extraction ratios of zinc oxide and silica. The mineral phase transformations were investigated by testing the phases of specimens obtained at different temperatures. The process was that silica reacted with molten NaOH to form Na2SiO3 at first, then transformed into Na4SiO4 with temperature rising. ZnCO3 and its decomposing product ZnO reacted with NaOH to form Na2ZnO2. Na2ZnSiO4 was also obtained. The reaction rate was investigated using unreacted shrinking core model. Two models used were chemical reaction at the particle surface and diffusion through the product layer. The results indicated that the reaction rate was combine-controlled by two models. The activation energy and frequency factor were obtained as 24.12 kJ/mol and 0.0682, respectively.

A novel process was proposed for the utilization of potash feldspar by roasting in the presence of sodium carbonate. The effects of roasting temperature, granularity, molar ratio of sodium carbonate to potash feldspar and roasting time on the silica extraction rate were investigated. Under the optimal roasting conditions, the silica extraction rate was 98%. The optimal conditions, determined using an orthogonal experiment, were found to be roasting temperature of 875 °C, potash feldspar granularity of 74–89 μm, molar ratio of sodium carbonate to potash feldspar of 1.2:1, and roasting time of 80 min. The kinetics of potash feldspar roasting in the presence of sodium carbonate was described by the shrinking core model and the reaction rate was found to be controlled by the chemical reaction at the particle surface. According to the Arrhenius expression, the activation energy was 164.99 kJ/mol, and the process could be expressed as [1-(1-α)1/3]=2.66×105 exp[-164990/(RT)] t.

Detailed information on the emperor penguin colonies is crucial for estimating total populations and analysing population migration. This study presents a new method for detecting colonies of emper...

(NH4)2SO4 roasting followed by water leaching to process nickel- chromium mixed metal oxidized (MO) ore was investigated. The optimal operating parameters were obtained after determining the influences of the molar ratio of (NH4)2SO4 to mixed oxidized ore, roasting temperature and roasting time on metal extractions. The extraction efficiencies of Ni, Fe, Mg, Al and Cr reached 94.02%, 87.87%, 84.14%, 74.00% and 41.49%, respectively. The transformation of mineral phases during roasting were identified by XRD analysis combining with TG-DTA curves and phases transformation analysis of analytic reagents with (NH4)2SO4. The phase transition process in experimental temperature range can be summarized as: MO to (NH4)2M(SO4)2 to MSO4 and M2O3 to (NH4)3M(SO4)3 to NH4M(SO4)2 to M2(SO4)3 (M is divalent and trivalent metallic element). The work demonstrates an effective process to treat nickel-chromium mixed metal oxidized ores. The reaction mechanism of Fe meets the chemical reaction control mechanism, while the reaction mechanism of Ni, Mg and Al follows the mixed control mechanism of the chemical reaction and diffusion controls.

An orthogonal test was used to optimize the reaction conditions of roasting zinc oxide ore using (NH4)2SO4. The optimized reaction conditions are defined as an (NH4)2SO4/zinc molar ratio of 1.4:1, a roasting temperature of 440°C, and a thermostatic time of 60 min. The molar ratio of (NH4)2SO4/zinc is the most predominant factor and the roasting temperature is the second significant factor that governs the zinc extraction. Thermogravimetric–differential thermal analysis was used for (NH4)2SO4 and zinc mixed in a molar ratio of 1.4:1 at the heating rates of 5, 10, 15, and 20 K·min−1. Two strong endothermic peaks indicate that the complex chemical reactions occur at approximately 290°C and 400°C. XRD analysis was employed to examine the transformations of mineral phases during roasting process. Kinetic parameters, including reaction apparent activation energy, reaction order, and frequency factor, were calculated by the Doyle–Ozawa and Kissinger methods. Corresponding to the two endothermic peaks, the kinetic equations were obtained.

A novel process was developed for the preparation of ultrafine silica from potash feldspar. In the first step, potash feldspar was roasted with Na2CO3 and was followed by leaching using NaOH solution to increase the levels of potassium, sodium, and aluminum in the solid residue. The leaching solution was then carbonated to yield ultrafine silica. The optimized reaction conditions in the roasting process were as follows: an Na2CO3-to-potash feldspar molar ratio of 1.1, a reaction temperature of 875°C, and a reaction time of 1.5 h. Under these conditions, the extraction rate of SiO2 was 98.13%. The optimized carbonation conditions included a final solution pH value of 9.0, a temperature of 40°C, a CO2 flow rate of 6 mL/min, a stirring intensity of 600 r/min, and an ethanol-to-water volume ratio of 1:9. The precipitation rate and granularity of the SiO2 particles were 99.63% and 200 nm, respectively. We confirmed the quality of the obtained ultrafine silica by comparing the recorded indexes with those specified in Chinese National Standard GB 25576―2010.

Thermodynamic analyses and kinetic studies were performed on zinc oxide ore treatment by (NH4)2SO4 roasting technology. The results show that it is theoretically feasible to realize a roasting reaction between the zinc oxide ore and (NH4)2SO4 in a temperature range of 573–723 K. The effects of reaction temperature and particle size on the extraction rate of zinc were also examined. It is found that a surface chemical reaction is the rate-controlling step in roasting kinetics. The calculated activation energy of this process is about 45.57 kJ/mol, and the kinetic model can be expressed as follows: 1 − (1 − α)1/3 = 30.85 exp(−45.57/RT)·t. An extraction ratio of zinc as high as 92% could be achieved under the optimum conditions.

Sea ice type is the most sensitive variables in Arctic ice monitoring and its detailed information is essential for ice situation evaluation, climate prediction and vessels navigating. In this study, we analyzed the different sea ice types with the Cryosat-2 (CS-2) SAR mode waveform data. The waveform of CS-2 data was describe by a set of parameters: pulse peakiness (PP), leading-edge width (LeW), trailing-edge width (TeW), stack standard deviation (SSD) and Maximum value of the echo waveform (Max)] and backscatter coefficient (Sigma0). Random forest (RF) classifier was chosen to classify ice type and the classification results were compared with Arctic and Antarctic Research Institute (AARI) operational ice charts. The results show that 85% of the Arctic surface type can be correctly classified from November 2015 to May 2016, 83% of the FYI can be correctly identified which is the domain ice type in Arctic. In comparison with Bayesian and K nearest-neighbor classifiers, the classification accuracy of RF increased by 5% and 3% respectively.

The ZnO powder was successfully obtained by calcining the basic zinc carbonate, which was synthesized from clinker digestion solution of zinc oxide ore using analytical Na2CO3. The factors of mol ratio of Na2CO3to ZnSO4and reaction temperature were discussed at stirring intensity 400 rpm. Both the obtained basic zinc carbonate and ZnO powders were characterized using XRD, EDS and SEM. The thermal decomposition of basic zinc carbonate was also investigated below 600°C. The results show that the ZnO powder was wurzite hexagonal structure and the well-crystallized ZnO powder was uniformly spherical particles and distributed in a narrow range.

Na2SO4solution that was obtained from ZnSO4solution after Zn2+precipitation using Na2CO3was used as raw material. The Na2SO4·7H2O crystallization was obtained through cooling the Na2SO4solution, and then the solution was cycled. The Na2SO4·7H2O was dried and then put into a porcelain boat located in a roaster. When the reaction between Na2SO4and CO ended, the Na2S was obtained. The influences of reaction temperature, reaction time and material thickness on the conversion rate were discussed. The appropriate reaction conditions were reaction temperature 675°C, reaction time 120min and material thickness less than 4cm.

Ultrafine ZnO powder was synthesized by precipitation method, using zinc sulfate and aqueous ammonium carbonate as raw material and precipitant, respectively. The influence of the concentration of aqueous ammonium carbonate on the precipitation rate of Zn2+ was discussed and their relationship was also illustrated. The precipitation rate of Zn2+ increased gradually with the mol ratio of CO32-to Zn2+, which reached up to more than 96% when the mol ratio was 1.2. In addition, the crystal structure and morphology of the precursor and ZnO powder were also characterized using XRD and SEM. The results indicated that ZnO powder was hexagon wurtzite structure and spherical figure with high purity and regular crystal form.

With zinc acetate used as raw material and polyethylene glycol employed as dispersant, ultrafine ZnO flower-like powder was successfully synthesized by hydrothermal method using NaOH and NH3·H2O as precipitants. The influences of the precipitants on the morphology of the ZnO powder were discussed. The as-synthesized ZnO flower-like powder was composed of lots of microrods with hexagon figure. The ZnO flower-like structures synthesized using NaOH were more regular and uniform than that obtained using NH3·H2O. The ZnO flower-like powder was hexagonal wurtzite structure with high purity. The exciton absorptions of the two ZnO flower-like powder both appeared at 300 nm in UV-VIS spectrum.

With zinc acetate and sodium hydroxide used as raw materials, while polyethylene glycol employed as dispersant agent, ultrafine zinc oxide flowers were successfully synthesized by hydrothermal method. The influence of the concentration of PEG20000 on the morphologies of ZnO flowers was discussed. The as-synthesized ZnO flowers consisted of microrods with hexagonal morphologies. The crystal structure and ultraviolet absorbing performance of ZnO flowers were also characterized using XRD, UV-VIS absorption spectrum. The results indicate that ZnO flowers are hexagonal wurtzite structure with high purity. There is a strong excition absorption peak at 300 nm in UV-VIS absorption spectrum and blue shift existed obviously.

The object of the present study was to investigate the levels of serum transferrin receptor (sTfR) and its response to Fe supplementation in Fe-deficient children and the role of sTfR in detecting Fe deficiency and assessing the efficacy of Fe supplementation. According to the diagnostic standard, 1006 children, aged 6–14 years in Fangshan district, Beijing, Peoples Republic of China, were divided into four groups: normal; Fe store depletion (IDs); Fe deficiency erythropoiesis (IDE); Fe deficiency anaemia (IDA). sTfR was determined and transferrin receptor-ferritin (TfR-F) index was calculated in 238 children, sixty-four normal and 174 Fe deficient. Children were administered a NaFeEDTA capsule containing 60 mg Fe once per week for the IDs and IDE groups and three times per week for the IDA group for nine consecutive weeks. The parameters reflecting Fe status and sTfR were determined before and after Fe supplementation. The levels of sTfR and TfR-F index in Fe-deficient children were significantly higher than those in the normal group. The receiver operating characteristic curve showed that sTfR has proper diagnostic efficacy for functional Fe deficiency. After Fe supplementation, the level of sTfR was significantly decreased in children with IDs, but not in children with IDE and IDA, while TfR-F index was significantly decreased in Fe-deficient children. sTfR is a reliable indicator for detecting functional Fe deficiency, and TfR-F index is a sensitive parameter for assessing the efficacy of Fe supplementation.

To observe the effects of marine protein peptide (MPP) on immunomodulating in mice and its possible mechanism.Female ICR mice (6-8 weeks old) were administered the MPP for 4 weeks with the dose of 0.22 g/kgBW, 0.45 g/kgBW and 1.35 g/kgBW. Spleen and thymus were weighted and cell-mediated immune functions, humoral immune functions, phagocytic functions of mononuclear phagocyte, NK cell activity assays, the T cell subpopulation of the spleen tissue by the flow cytometer and the concentrations of cytokines in serum by cytometric bead array were examined.The capacity of lymphocyte proliferation induced by Con A (0.33 +/- 0.21), DTH response (0.36 +/- 0.11) mm in MPP 0.22 g/kgBW group were significantly increased in comparison with these values in control group (0.15 +/- 0.10) and (0.21 +/- 0.10)mm, respectively, P0.05. IgM-PFC number of MPP 0.22 g/kgBW group (1.64 +/- 0.06), 0.45 g/kgBW group (1.59 +/- 0.05) and 1.35 g/kgBW group (1.56 +/- 0.10) were higher than those in control group (1.38 +/- 0.10), P0.01; and the level of serum HC50 of MPP 0.22 g/kgBW group (141.00 +/- 23.00) and 0.45 g/kgBW group (130.40 +/- 33.20) were greater than the control (100.30 +/- 19.40) , P0.01. The activity of NK cells in MPP 0.22 g/kgBW group (1.672 +/- 0.142) was significantly elevated in comparison with this value in control group (1.392 +/- 0.182), P0.05. The percentage of CD4 T helper (Th) cell in spleen of MPP 0.22 g/kgBW group (32.84 +/- 3.776)% and 0.45 g/kgBW group (32.42 +/- 3.507) % was higher than those in control group (25.06 +/- 0.354) %, P0.05. The concentrations of IL-2 in serum of MPP 0.22 g/kgBW group 181.06 pg/ml, 0.45 g/kgBW group 94.84 pg/ml and 1.35 g/kgBW group 102.61 pg/ml were higher than those in control group 0.50 pg/ml, P0.05; and the level of IL-5 of MPP 0.22 g/kgBW group (38.31) pg/ml was greater than the control 0.50 pg/ml, P0.05. Nevertheless, no obvious effects on weight increasing, the ratio of immune organ and body weight and phagocytosis capacity were observed in our study.MPP could improve the immune functions in mice, and might be by the mechanism of enhancing the function of Th cells stimulating the secretion of Th1 and Th2 type cell cytokines.

We aimed to study the response of serum transferrin receptors (sTfR) to Fe supplementation in women of childbearing age with Fe-deficiency erythropoiesis (IDE) and Fe-deficiency anaemia (IDA). Primary screening was performed in 942 women ranging in age from 18 to 45 years. After Fe-related biochemical indices such as serum ferritin, Zn protoporphyrin and Hb were determined, the subjects were divided into four groups: normal, Fe store depletion, IDE and IDA. A total of 131 women were randomly selected from the normal, IDE and IDA groups. Subsequently, seventy-six women with IDE and IDA were given various doses of Fe (14 mg/d for IDE; 28 mg/d for IDA) with ferrousl-threonate capsules for twelve consecutive weeks. After receiving Fe supplements, the levels of Fe and sTfR were determined at weeks 0, 3, 6, 9 and 12.The levels of sTfR in women of childbearing age with IDE and IDA were significantly higher than those in the normal group. After receiving Fe supplements, the levels of sTfR were significantly decreased in women of childbearing age with IDE and IDA, while the levels of serum ferritin were significantly increased. In conclusion, STfR can be used as a reliable indicator for assessing the efficacy of Fe supplements.

To understand iron nutritional status in school-age children, incidence of the sub-clinical iron deficiency (SID) and effect of iron supplementation on SID in the rural school-age children from mountainous areas of Beijing.The dietary survey and food frequency questionnaire survey were conducted in 1,012 school children aged 7 - 13 at rural mountainous areas of Fangshan District, Beijing, and their blood samples were collected for analyzing biochemical indicators for iron nutrition. Two hundred and sixty-seven children with IDs (iron deficiency store) and IDE (iron deficiency erythropoiesis), based on screening criteria for iron-deficiency anemia, received an iron supplementation (NaFeEDTA) capsule (containing 60 mg iron element) weekly, and those with IDA (iron deficiency anemia) received NaFeEDTA capsule thrice weekly for nine weeks. Blood biochemical indicators for iron nutrition were determined repeatedly and compared with those before and after the intervention.The daily average intakes of energy, protein, iron and vitamin C in school children of all age groups reached the daily recommended criteria (85% of the RNIs), but the proportion of heme in dietary iron constitution was lower. The average blood biochemical indicators for iron nutrition were as follows: serum ferritin (SF) (50.83 +/- 33.09) micro g/L, free erythrocyte protoporphyrin (FEP) (489.44 +/- 219.61) micro g/L, hemoglobin (Hb) (130.57 +/- 10.82) g/L, and the ratio of FEP/Hb (3.83 +/- 1.96), respectively. Incidence of total iron deficiency in rural children was 26.5%, with proportions of iron deficiency (IDs), iron deficiency erythropoiesis (IDE), and iron deficiency anemia (IDA) of 15.5%, 7.1%, and 3.9% respectively. SID accounted for 85.4% of the total iron deficiency, which was 5.8 times as much as IDA. With iron supplementation for 9 weeks, the hematdogical index of iron increased significantly and returned to the normal level.The incidence of subclinical iron deficiency in the rural school-age children was insidious and should be attached more importance, which was helpful to its early recognition and intervention. Iron supplementation is important for children with SID to prevent and decrease the occurrence of IDA.