氧化钙或氢氧化钙与浓碱铝酸钠溶液的反应特性

研究了氧化钙、氢氧化钙与浓碱铝酸钠溶液的反应特性,在相同条件下,氧化钙的反应活性高于氢氧化钙,这归结于氧化钙在水化放出大量热量的同时,固相颗凿细化,比表面积增大。较多量的氧化钙加入反应体系后,体系主要因固相颗粒团聚容易发生膨胀。玎的扫描电镜分析表明：加入表面活性剂后,表面活必有因吸附“挤占”了新生因相表面吸附的小分子,破坏或削弱了体系的团聚,从而消除和体系的膨胀;同时,表面活性剂的会降低了固液界面     

Fe-PGMs合金废电解液溶析结晶制备硫酸亚铁

以Fe-PGMs合金电解精炼产生的废电解液为原料,无水乙醇作为溶析剂,使用溶析结晶法从废电解液中将硫酸亚铁结晶析出。考察了溶析时间、乙醇与水溶液体积比、溶析温度、搅拌速度、陈化时间、无水乙醇滴加方式对硫酸亚铁结晶率的影响。结果表明,在溶析时间60 min、无水乙醇与水溶液体积比为1:1、溶析温度10 ℃、搅拌速度200 r/min、陈化时间60 min、乙醇滴加方式为逐滴加入时硫酸亚铁结晶率达到最大92.98%。此工艺避免了电解过程中废电解液对环境的污染,实现了电解Fe-PGMs合金中电解液及Fe-PGMs合金酸浸液的循环利用。     

Comparative study on simultaneous removal of calcium and sulfate ions from flotation recycling water by aluminum hydroxide

Due to the environmental policies and economic reasons, the water used in some flotation operations of complex sulfide ores is recirculated, causing the ion concentration of some species to increase over time, affecting the flotation of the minerals of interest. In this work, an experimental and thermodynamic analysis of the synthetic solutions was presented with a high content of calcium and sulfate ions. The study focused on evaluating the use of two aluminum compounds for the precipitation of Ca²⁺ and SO₄^2? in the form of ettringite. The amorphous aluminum hydroxide was found to be more efficient than the crystalline one, giving rise to 83% calcium and 91% sulfate removal. The XRD analysis of the solids showed the main reaction product of ettringite, accompanied by small amounts of calcite, due to the absorption of atmospheric carbon dioxide. The final solution after the chemical treatment showed residual calcium and sulfate concentrations below 200 mg/L. Finally, the kinetics of calcium removal appeared to correspond to a second order reaction with respect to calcium concentration, with an apparent activation energy of 53.48 kJ/mol, which may suggest that the ettringite precipitation process is governed by the chemical reaction.     

Influence of Ca/P ratios of starting solutions on the crystallization of amorphous calcium phosphate to hydroxyapatite

Amorphous calcium phosphate was precipitated at 20°C from highly supersaturated solutions having compositions of 1.5≤Ca/P≤2.0 at a pH=11. The phase evolution and morphological changes in precipitates as a function of aging time were investigated using XRD and TEM analyses. Higher Ca/P molar ratio of the starting solution resulted in faster crystallization to hydroxyapatite. Shorter induction times for crystallization were attributed to smaller particle sizes of the initially precipitated ACP as well as to the Ca-rich environment. Nucleation of the hydroxyapatite phase was suggested to be a major mechanism of crystallization, which was supported by the observation that no considerable growth of hydroxyapatite occurred during further aging. The increase in the number of HAp nuclei was accompanied by a size reduction of particles of amorphous phase.     

硫酸镍铵复盐结晶法分离回收铜电解液中的镍（英文）

研究采用硫酸镍铵复盐结晶从铜电解液中分离回收镍的方法。研究发现,在相同温度的溶液中,硫酸铜的溶解度小于硫酸镍的溶解度,而硫酸铜铵的溶解度大于硫酸镍铵的溶解度。因此,加入(NH₄)₂SO₄可使铜电解液中的镍选择性结晶析出。按(NH₄)₂SO₄/NiSO₄摩尔比≤0.8加入(NH₄)₂SO₄,在-15℃冷冻结晶10 h,可使其中的镍以Ni(NH₄)₂(SO₄)₂·6H₂O的形式结晶析出。将所得结晶物热解,再将热解产物加水溶解,最后将溶解液浓缩结晶得到合格的NiSO₄·6H₂O产品。复盐结晶法是一种清洁环保、经济高效的从铜电解液中分离回收镍的方法。     

铝酸钠溶液添加硫酸钙脱硅过程的研究

以硫酸钙作为脱硅剂,对铝酸钠溶液脱硅条件和结果进行了研究。实验中考察了脱硅温度、脱硅时间、脱硅剂的用量、搅拌速度对脱硅效果的影响,确定了最佳脱硅工艺条件:在95℃的温度下添加硫酸钙30g/L深度脱硅90min,精制液的硅量指数达3681。对硫酸钙脱硅后所形成的硅渣进行XRD测定,并且对硫酸钙的脱硅机理进行了分析。     

Synthesis and reaction behavior of calcium silicate hydrate in basic system

1　INTRODUCTIONIt skeytoseparatealuminafromsilicainaluminaproductionbyBayerorsinteringprocess .Whethersilicachangestosodiumaluminosilicatehydrateorhydro garnet(bothtitleddesilicationproduct,DSP) ,bothcontainso daoralumina .IfDSPisdischargedoutdirectly ,alargeamountofsodaandaluminawillbewasted ,meanwhiledischargedDSPwillresultinheavyenvironmentalpollu tion .InpresentitcostsalottorecoveraluminaandsodafromDSPbysinteringprocess[1] .Soitisurgenttodevel opnewhydro processtechnologytorecove…     

探讨万古霉素硫酸钙联合超短波治疗创伤性骨髓炎临床疗效及安全性

目的: 探讨万古霉素硫酸钙联合超短波治疗创伤性骨髓炎临床疗效及安全性。方法: 74例创伤性骨髓炎患者随机分为对照组（37例）与试验组（37例）,2组均给予常规治疗以及对症治疗,手术前3 d给予注射用盐酸去甲万古霉素0.8 g/d静滴,每日2次,选取硫酸钙骨移植替代物5～10 g与盐酸去甲万古霉素1 g加水调制成糊状,术后给予注射用盐酸去甲万古霉素0.8 g/d,每日2次,试验组术后联合超短波治疗,2组患者一个周期均为28 d,共治疗2个周期。比较2组临床疗效、治疗前后血液流变学指标、血清C 反应蛋白（CRP）、血清肿瘤坏死因子（TNF-α）、核因子-κB(NF-κB）以及不良反应发生情况。结果: 治疗后,对照组临床总有效率为78.38%,显著低于试验组的97.30% (P<0.05)。治疗后,试验组的红细胞聚集指数高于对照组（P<0.05）,血浆粘度、全血粘度、红细胞沉降率（ESR）水平低于对照组（P<0.05）。试验组血清CRP、TNF-α、NF-κB水平显著低于对照组 (P<0.05)。对照组不良反应发生率为13.51%,试验组为8.11%,差异无统计学意义(P＞0.05)。结论: 万古霉素硫酸钙联合超短波治疗创伤性骨髓炎的临床疗效显著,安全性高。     

Thermodynamics and kinetics of fluoride removal from simulated zinc sulfate solution by La(III)-modified zeolite

To understand the mechanism of fluoride removal from the simulated zinc sulfate solution by the La(III)-modified zeolite, the adsorbent was characterized by XRD, SEM and EDS. The effects of absorbent dose and contact time, the adsorption isotherms and the sorption kinetics were investigated. The experimental results were compatible with the Langmuir isotherm model. The theoretical maximum adsorption capacities are 20.83 and 23.04 mg/g at 303 and 313 K, respectively. And the physisorption is revealed using the Temkin isotherm model and the D–R isotherm model. The sorption process is more suitable by the pseudo-second-order kinetic models. Thermodynamic parameters such as standard free energy change (ΔG^Θ<0 kJ/mol), standard enthalpy change (ΔH^Θ=8.28 kJ/mol) and standard entropy change (ΔS^Θ=0.030 kJ/(mol·K)) indicate the spontaneity of adsorption and endothermic physical sorption. Furthermore, the fluoride concentration in the industrial zinc sulfate solution decreases from 98.05 to 44.09 mg/L with the adsorbent dosage of 15 g/L.     

Glass-forming ability and crystallization of Mg-Ni amorphous alloys with Y addition

Mg86.33Ni13.67-xYx(x=0, 1, 3, 6, 10) amorphous alloys were obtained by single-roller melt-spinning technique and the effect of Y addition on the glass forming ability(GFA), crystallization and micro-hardness of Mg-Ni alloys were studied. The results show that the GFA of Mg86.33Ni13.67-xYx(x=0, 1, 3, 6, 10) is improved successfully with the Y addition. The highest GFA appeares at x=6, while the reduced glass transition temperature (Trg) is 0.5225 and the supercooled liquid region(ΔTx) is 42.06 K; the positio...     

Crystallinity and crystallization mechanism of lithium X-ray diffractometry aluminosilicate glass by

The crystallinity of lithium aluminosilicate（LAS） glass after crystallization were studied at different temperatures by X-ray diffractometry and the crystallinity of the standard glass ceramic with known crystal and glass phases was examined. The crystallization mechanism of LAS glass was analyzed by the crystallinity, with a formula relating the crystallinity （X） and temperature （T）. The results show that the calculated crystaUinity of LAS glass by XRD increases with the erystaUization temperature, in the range of 40%-50%, which is close to the calculated ones of standard samples with spodumene quartz ratio of 40%-70%. The activation energy of LAS glass is different within different temperature ranges; nEe is 125.44 kJ/mol at 710-810 ℃ and nEe is 17.42 kJ/mol at 810-980 ℃, which indicates different crystallization mechanisms. It has been proved that the required energy for crystallization of glass in the lower temperature range includes the interracial energy between glass and crystalline phase and the free energy difference of atoms in structures of glass and crystal, and in the higher temperature ranges only the interfacial energy between glass and crystalline phase is considered.     

Crystallinity and crystallization mechanism of lithium aluminosilicate glass by X-ray diffractometry

1 Introduction Lithium aluminosilicate(LAS) glass-ceramics has been one of the most intensively studied systems because of its great creep resistance, very low thermal expansion characteristics and excellent thermal shock resistance [1?3]. It has been co…     

放电等离子烧结-非晶晶化法合成Ti7oNb7.8Cu8.4Ni7.2Al6.6复合材料

采用机械合金化制备不含和含2%(体积分数)B4C的钛基非晶合金粉末,随后采用放电等离子烧结-非晶晶化法合成不含／含(TiB+TiC)的Ti7oNb7.8Cu8.4Ni7.2Al6.6超细晶／细晶钛基复合材料;运用X射线衍射分析(XRD)、差示扫描量热分析(DSC)、扫描电子显微镜(SEM)和万能材料试验机等对制备的钛基非晶粉末和超细晶／细晶钛基复合材料进行表征.结果表明高能球磨80h的钛基粉末中主要为非晶相,B4C颗粒的加入对钛基粉末的玻璃转变温度、晶化温度和晶化焓有显著的影响.另外,不含／含(TiB+TiC)的复合材料的显微硬度分别为5.47和5.33GPa;以50K/min升温到1223K并保温10min获得的Ti70Nb7.8Cu8.4Ni7.2Al6.6块体试样的断裂强度和断裂应变分别为2098MPa和11.5%.     

二段脱铜液还原结晶法脱砷新工艺

对铜电解液脱砷方法进行研究,提出以二段脱铜液为原料,采用SO2还原结晶法脱砷新工艺。在二段脱铜液中通入SO2,将其中的As(Ⅴ)还原成As(Ⅲ),还原后的溶液通过蒸发结晶析出As2O3,达到二段脱铜液脱砷的目的。结果表明:当As(Ⅴ)浓度为12.41 g/L、H2SO4浓度为253.00 g/L、反应温度为60℃时,向二段脱铜液中通入SO290 min后静置90 min,二段脱铜液中As(Ⅴ)的还原率达到94.54%。还原后的溶液进行蒸发结晶,当蒸发前与结晶后的体积比(V0:V1)为3.5时,砷的脱除率达到91.33%,结晶产物为As2O3。与传统脱砷工艺相比,新工艺具有操作简单、成本低廉及砷的脱除效果明显等优势。     

核化和晶化温度对温石棉尾矿制备微晶玻璃的影响

以温石棉尾矿、石灰石和石英砂为主要原料,通过不同的热处理过程制备了微晶玻璃。借助DTA、XRD及SEM等分析测试手段,研究了核化和晶化温度对微晶玻璃析晶行为、显微形貌及抗压强度的影响。结果表明:随着热处理温度的升高,微晶玻璃主晶相的种类没有改变,但主晶相衍射峰的强度呈现先增强后减小的趋势。当核化温度为820℃,晶化温度为1050℃时,微晶玻璃样品形成致密的柱状细晶结构,抗压强度达到最大值523 MPa。     

Mechanical properties and structure of zirconia-mullite ceramics prepared by in-situ controlled crystallization of Si-Al-Zr-O amorphous bulk

Zirconia-mullite nano-composite ceramics were fabricated by in-situ controlled crystallization of Si-Al-Zr-O amorphous bulk, which were first treated at 900-1 000 ℃ for nucleation, then treated at higher temperature for crystallization to obtain ultra-fine zirconia-mullite composite ceramics. The effects of treating temperature and ZrO2 addition on mechanical properties and microstructure were analyzed. A unique structure in which there are a lot of near equiaxed t-ZrO2 grains and fine yield-cracks has been developed in the samples with 15% zirconia addition treated at 1 150 ℃. This specific microstructure is much more effective in toughening ceramics matrix and results in the best mechanical properties. The flexural strength and fracture toughness are 520 MPa and 5.13 MPa·m1/2, respectively. Either higher zirconia addition or higher crystallization temperature will produce large size rod-like ZrO2 and mullite grains, which are of negative effect on mechanical properties of this new composite ceramics.     

固溶处理对含长周期结构Mg97Zn1Y2合金显微组织及阻尼性能影响

通过光学显微镜、扫描电镜分析了铸态及固溶处理态Mg97Zn1Y2合金的显微组织,并利用EDS,XRD进行了物相分析。研究发现固溶处理后,Mg97Zn1Y2合金中的长周期结构相发生长大,由离散分布变为连续分布。阻尼测试结果显示,固溶处理后Mg97Zn1Y2合金阻尼性能下降。通过对铸态及固溶处理态Mg97Zn1Y2合金进行阻尼-温度谱分析,发现存在两个内耗峰：P1内耗峰位置在150-250℃附近,峰宽很宽,是由位错机制而引起的内耗峰;P2内耗峰位置在350-500℃附近,初步认为是晶界内耗峰。     

Thermodynamic and experimental studies on removal of calcium and sulfate ions from recycling water of complex sulfide flotation operations

A chemical method for removing calcium sulfate saturated solutions (0.016 mol/L CaSO₄) using barium chloride (BaCl₂·2H₂O) and sodium phosphate (Na₃PO₄) was experimentally studied. The main interest is to remove these ions from the solution through the precipitation of two solid species: sulfate (SO₄²⁻) as barite (BaSO₄), and calcium (Ca²⁺) as hydroxyapatite (Ca₅(PO₄)₃OH). Additionally, a solid/liquid separation method (i.e., flotation) was explored, using oleic acid and dodecylamine as collectors. The results show that, the chemical treatment of saturated solutions at 60 °C, pH 11.5 and using 3.9 g/L BaCl₂·2H₂O and 1.6 g/L Na₃PO₄, promotes the precipitation of barium sulfate and calcium-deficient hydroxyapatite (Ca_10–x(HPO₄)_x(PO₄)_6–x(OH)_2–x), with residual concentrations of calcium and sulfate below 0.10 and 5 mg/L, respectively. The residual calcium concentration increases to 28 mg/L when using the same amount of reactants, at temperature and pH values below those quoted. The highest flotation recovery of hydroxyapatite with oleic acid at pH 9.5 was about 80%, while that of barite floated with dodecylamine at pH 6.5 was about 90%.     

Effect of temperature,oxygen partial pressure and calcium lignosulphonate on chalcopyrite dissolution in sulfuric acid solution

The pressure leaching mechanism of chalcopyrite was studied by both leaching tests and in-situ electrochemical measurements. The effects of leaching temperature, oxygen partial pressure, and calcium lignosulphonate, on copper extraction and iron extraction of chalcopyrite pressure leaching were investigated. The leaching rate is accelerated by increasing the leaching temperature from 120 to 150 °C and increasing oxygen partial pressure to 0.7 MPa. The release of iron is faster than that of copper due to the formation of iron-depleted sulfides. Under the optimal leaching conditions without calcium lignosulphonate, the copper and iron extraction rates are 79% and 81%, respectively. The leaching process is mixedly controlled by surface reaction and product layer diffusion with an activation energy of 36.61 kJ/mol. Calcium lignosulphonate can effectively remove the sulfur passive layer, and the activation energy is 45.59 kJ/mol, suggesting that the leaching process with calcium lignosulphonate is controlled by surface chemical reactions. Elemental sulfur is the main leaching product, which is mixed with iron-depleted sulfides and leads to the passivation of chalcopyrite. Electrochemical studies suggest that increasing the oxygen partial pressure leads to increasing the cathodic reaction rate and weakening the passivation of chalcopyrite.