Dry Mix Slag—High-Calcium Fly Ash Binder. Part Two: Durability

This work investigates durability of cement-free mortars with a binder comprised of ground granulated blast furnace slag (GGBFS) activated by high-calcium fly ash (HCFA) and sodium carbonate (Na2CO3): the soundness, sulfate resistance, alkali-silica reactivity and efflorescence factors are considered. Results of tests show that such mortars are resistant to alkali-silica expansion. Mortars are also sulfate-resistant when the amount of HCFA in the complex binder is within a limit of 10 wt%. The fineness of fly ash determines its’ ability to activate GGBFS hydration, and influence soundness of the binder, early strength development, sulfate resistance and efflorescence behavior. The present article is a continuation of authors’ work, previously published in MSA, Vol. 14, 240-254.

Steam gasification reactivity of a high-sodium coal fly ash obtained from a pilot scale CFB gasifier

Circulating fluidized bed （CFB） gasification has several advantages for the utilization of low rank coals. However, the carbon content of fly ash is usually very high, which greatly infuences the gasification efficiency. The purpose of this research is to investigate the gasification reactivity of a high-sodium Zhundong （ZD） coal fly ash obtained from a pilot-scale 2.5 t/d CFB gasification system. The experiments were carried out in a thermogravimetric analyzer with steam as gasification agent, and fast pyrolyzed ZD char was also investigated as a reference sample. The results show that increasing temperature accelerates the gasification rate both for fly ash and ZD char. Fly ash has higher gasification rate at the initial gasification stage. On the contrary, ZD char has higher reaction rate even at higher carbon conversion stage. Via distributed activation energy model, the average activation energy of ZD char and fly ash is calculated to be 94.4 and 91.2 kJ/mol, respectively. The integrated model study reveals that the reaction order of ZD char is about 0.74, whereas the reaction order of fly ash decreases from 1 to 0.59 when temperature increases from 900 to 1050 ℃. The gasification reactivity of ZD coal fly ash is quite different with literature research on those fly ashes with rarely little catalytic elements in coal ashes. The interesting results are related with the unique properties of ZD coal fly ash and the transformation of sodium during gasification process.

Manifestations in Corrosion Prophase of Ultra-high Strength Steel 30CrMnSiNi2 A in Sodium Chloride Solutions

The corrosion behaviors of ultra-high strength steel 30CrMnSiNi2A in sodium chloride solution were studied by weight loss and electrochemical methods. The morphology of corrosion products was observed using scanning electron microscopy（SEM） and the composition was analyzed using an energy dispersive spectroscopy（EDS） and X-Ray diffraction （XRD）. The experimental results showed that the corrosion came from pitting corrosion and the rust layer was composed of outer rust layer γ-FeOOH and inner rust layer Fe_2O_3 with a little β-FeOOH. The correlation between corrosion rate and test time accorded with exponential rule. The corrosion current measured by polarization methods was higher than that calculated by weight loss method after a long-time immersion, the main reason was that,β-FeOOH and γ-Fe_2O_3 transformed by γ-FeOOH led to overestimating corrosion rate. The processes of corrosion prophase were obtained from XRD and EIS results. The corrosion product, Fe（OH）_2 formed at the initial stage stayed at a non-steady state and then consequently transferred to γ-FeOOH, γ-Fe_2O_3 or β-FeOOH.

RAMAN SPECTRA OF SODIUM ALUMINATE SOLUTIONS WITH HIGH-CAUSTIC RATIO AND HIGH CONCENTRATION

The constitution of high-caustic ratio and highly concentrated sodium aluminate solutions has been investigated by Raman spectra method.By comparison with the Raman spectra of crystalline solids of Ca_3[Al(OH)_6]_2 and Ba_2[Al_2(OH)_(10)],it can be concluded that AI(OH)_6^(3-)ion and perhaps its polymers may be formed in these solutions.

Study on Influencing Factors and Kinetics of Removal of Ammonia Nitrogen from High Salinity Wastewater by Sodium Hypochlorite Oxidation

The influencing factors and kinetics of oxidative degradation of ammonia nitrogen in high salinity wastewater by sodium hypochlorite oxidation( Na Cl O) were studied. The results showed that the degradation process of ammonia nitrogen by sodium hypochlorite accorded with a pseudo first-order kinetics model,and the influencing factors included Na Cl O dosage,initial concentration of ammonia nitrogen,salinity,temperature,and so on. When Na Cl O dosage was 0. 6%( MCl∶ MN= 13. 76),the reaction rate constant was up to 0. 015 75 min^(-1). The higher the initial concentration of ammonia nitrogen was,the worse the effect of oxidation reaction was. When the initial concentration did not exceed 45 mg/L,the effect on oxidation reaction rate constant increased with the increase of the initial concentration. Low salinity had no effect on ammonia nitrogen oxidation.When salinity was higher than 2. 0%,the inhibition effect on ammonia nitrogen oxidation would increase,and the reaction rate constant decreased obviously with the increase of salinity. The improvement of reaction temperature was beneficial to ammonia oxidation degradation. As temperature increased from 10 to 35 ℃,the reaction rate constant rose from 0. 00188 to 0. 01043 min^(-1).

Preparation of High－purity Sodium Tungstate from Low－grade Tung－sten－concentrate with a High Content of Calcium and Other Impurities

A new technological process for production of talium tungstate from low-grade tungsten-concentrate witha high content of calcium and other impurities has been studied. The experiments showed that average tungstenleaching efficiency of more than 96. 92 % can be obtained with a low NaOH consumption by using the mechani-cal activating caustic decomposition , and the content of main impurities (P, As, Si) in Na_2WO_4 solution ob-tained is competitive with that from standard wolframite concentrate by traditional caustic decomposition. Afterrecovering caustic liquor by first crystallization, molylxlenum is removed from Na_2WO_4 solution by ion ex-change method. High-purity sodium tungstate is obtained by second crystallization of Na_2WO_4 solution. Thistechnology has the advantages of good adaptability for raw materials, high removing efficiency of impurities,high tungsten recovery and high economic benefit.

Mechanism of Increase in Strength of Sodium Silicate-bonded Sand by Silica Sand Surface Modified in High Temperature.

With the aid of XRD, SEM and EDS etc., there is absorbed film on sand grain surface, high temperature modify makes the film sintered firmly on sand grain surface. Thus it changes physical and chemical characteristics of the film and sand grain surface, improves the wetting properties greatly, makes the fracture features of bonding bridge change from the adhesive to the cohesive and raises the strength of sodium silicate-bonded sand.

One step graft copolymerization of acrylic acid and sodium styrene sulfonate onto high-density polyethylene film by preirradiation method

High-density polyethylene (HDPE) films were irradiated by 60Co gamma ray with a dose of 100 kGy in air and then immersed in aqueous solution of acrylic acid (AA) and sodium styrene sulfonate (SSS) at different temperature. The effects of grafting conditions such as temperature, reaction time, Mohr’s salt concentration, and total concentration of monomer on grafting yield were studied. Both grafting yield of AA and SSS onto HDPE respectively increases with total concentration of monomers. The highest grafting yield was observed at 3 mol/L monomers where the grafted PE swelled to the largest extent in the monomers mixture. The grafting yield increases with reaction time and then levels off. At higher temperature, the grafting yield decreases with Mohr’s salt concentration, but increases at low temperature when Mohr’s salt concentration is 0.083%. Which can be interpreted that in the presence of Fe2+ diperoxides and hydroperoxides may decompose at low temperature to form radical which can initiate the grafting. The physical and chemical properties of grafting films were also investigated.

Stability indicating high performance thin-layer chromatographic method for simultaneous estimation of pantoprazole sodium and itopride hydrochloride in combined dosage form

A specific, precise and stability indicating high-performance thin-layer chromatographic method for simultaneous estimation of pantoprazole sodium and itopride hydrochloride in pharmaceutical formulations was developed and validated. The method employed TLC aluminium plates precoated with silica gel 60F254 as the stationary phase. The solvent system consisted of methanol：water：ammonium acetate; 4.0：1.0：0.5 （v/v/v）. This system was found to give compact and dense spots for both itopride hydrochloride （Rf value of 0.55__＋0.02） and pantoprazole sodium （Rf value of 0.85＋0.04）. Densitometric analysis of both drugs was carried out in the reflectance- absorbance mode at 289 nm. The linear regression analysis data for the calibration plots showed a good linear relationship with R2=0.9988___0.0012 in the concentration range of 100--400 ng for pantoprazole sodium. Also, the linear regression analysis data for the calibration plots showed a good linear relationship with R2=0.9990_＋0.0008 in the concentration range of 200-1200 ng for itopride hydrochloride. The method was validated for specificity, precision, robustness and recovery. Statistical analysis proves that the method is repeatable and selective for the estimation of both the said drugs. As the method could effectively separate the drug from its degradation products, it can be employed as a stability indicating method.

Development of lithium-free P2-type high-sodium content cathode materials with enhanced cycle and air stability for sodium-ion batteries

The effect of partial substitution of Mg for Ni on a high-sodium and lithium-free layered P2-type Na_(45/54)Mg_(6)/_(54)Ni_(12/54)Mn_(34/54)O_(2) cathode with high initial Coulombic efficiency and excellent cyclic stability has been investigated in this study.Based on the crystal structural analysis,the Mg doping can retain the P2 structure up to 4.3 V,thus restraining the detrimental phase transformation of P2-02during the Na-ion intercalation/deintercalation process.Therefore,the obtained Mg-doped P2-type cathode exhibits a reversible specific capacity of 109 mAh·g^(-1) at 0.1C between 2.0 and 4.3 V and a retention rate of 81.5% after 200cycles at 1C.In addition,the full cell consisting of Mg-doped P2-type cathode and hard carbon anode shows a capacity retention rate of 85.6% after 100 cycles.This study provides new insight into the development of durable cathode materials for sodium-ion batteries.

高碱煤热转化过程中钠的释出特性实验研究

为研究高碱煤热转化过程中钠的释出特性,采用原煤和水萃取煤分别进行燃烧实验和热解实验来对比分析高碱煤和低碱煤中钠的释出特性,探究不同煤质的煤样在燃烧时煤样中不同赋存形态钠的释出特性变化以及气氛变化对钠释出的影响。结果表明:在进行燃烧实验时,高碱煤在300~500℃时钠的释出量增加缓慢,在500~1100℃时钠的释出量增加较快,低碱煤在300~500℃时钠的释出量增加较快,在500~1100℃时钠的释出量增加缓慢,由此可知煤质是影响钠释出的主要原因之一,钠的释出特性会因煤质中成分差异而受到较大影响;燃烧和热解2种不同气氛下钠释出特性相似,热解过程中钠释出率变化平缓,且热解过程中钠释出率会比燃烧过程低7.0%左右;有机钠和水溶性钠2种不同赋存形态钠因释出途径不同而导致释出特性有所差异。

池式钠冷快堆堆内自然循环余热排出设计研究

基于装量功率比约为1 t/MW的较典型池式钠冷大功率快堆的堆内自然循环设计,采用ERAC程序,对两组4种不同事故余热排出系统(DHRS)输入条件下,反应堆在紧急停堆后堆内的自然循环余热排出特性进行分析。结果表明,从DHRS启用到其对堆芯产生显著冷却效应,需要较长时间,在千秒量级。在该段时间内,堆芯余热的排出依靠反应堆固有的热工流体安全特性。随后,在堆内关键温度上升到限值之前启用DHRS带出池内热量,使堆内关键温度处于下降趋势即可满足安全要求;相比将独立热交换器(DHX)布置在冷池,将其布置在热池时,热池温度及主容器壁温相对要低,这有利于主容器的温度控制,其效果要优于布置于冷池。另外,不同布置会对堆芯盒内、盒间流流量产生影响,但总体上对堆芯的冷却效应影响不大;池式钠冷快堆余热排出设计中,要充分利用固有热工流体安全特性,降低对DHRS的时效性要求。可以考虑将全部的DHX都布置在热池,并缩小设备体积、降低散热功率设计值,或在不降低安全性的前提下选用其他更经济便捷的有效方式等,以此大幅降低余热排出设备投入成本,降低反应堆运行成本,提高经济性。本文研究结果可为我国后续的商用快堆、一体化快堆等池式液态金属堆的堆内自然循环设计提供重要参考。

高温钠热管启动传热振荡及热疲劳安全分析

高温热管的启动是复杂的相变及流动过程,若发生传热振荡将造成温度波动,进而影响热管堆运行安全。本文通过实验及仿真方法研究高温钠热管在启动过程中的传热振荡现象及热疲劳后果。在竖直工况中,不同输入热流密度将引起钠蒸发速率变化,呈现不同振荡特征;热流密度提升时振幅下降,周期缩短;振荡发生时,若输入功率骤降,波形将从锯齿状转变为梯形状;在水平工况中,传热振荡被明显抑制。热管在堆内发生传热振荡时,应力风险区为热管蒸发段内壁中部;异相振荡时相较同相振荡工况应力均值升高,振幅下降,疲劳损伤减轻;当安全因子K低于1.4时热管不存在疲劳失效风险,K达1.4以上后损伤逐渐显著;其中同相工况疲劳损伤最严重,K=1.6时管壁材料疲劳寿命已降低至3.29年。本研究对高温钠热管传热振荡的机理分析及完善热管可靠性评估具有重要意义。

Dry Mix Slag—High-Calcium Fly Ash Binder. Part One: Hydration and Mechanical Properties

High-calcium fly ash (HCFA)—a residue of high-temperature coal combustion at thermal power plants, in combination with sodium carbonate presents an effective hardening activator of ground granulated blast-furnace slag (GGBFS). Substitution of 10% - 30% of GGBFS by HCFA and premixing of 1% - 3% Na2CO3 to this dry binary binder was discovered to give mortar compression strength of 10 - 30 to 30 - 45 MPa at 7 and 28 days when moist cured at ambient temperature. High-calcium fly ash produced from low-temperature combustion of fuel, like in circulating fluidized bed technology, reacts with water readily and is itself a good hardening activator for GGBFS, so introduction of Na2CO3 into such mix has no noticeable effect on the mortar strength. However, low-temperature HCFA has higher water demand, and the strength of mortar is compromised by this factor. As of today, our research is still ongoing, and we expect to publish more data on different aspects of durability of proposed GGBFS-HCFA binder later.

某难选高次生铜硫化铜矿石选矿试验研究及现场技术改造

通过对某高次生铜硫化铜矿矿石的工艺矿物学分析以及矿石特性的研究,确定了合适的浮选流程,并进行了不同条件的选矿试验。试验结果表明:通过使用高效捕收剂酯-305、添加适量的Na 2 S活化铜、采用中矿集中返回再磨工艺,可取得了较好的技术指标。在试验的基础上现场实施了简单的流程改造,对于含Cu 0.92%的原矿经过磨矿分级以及两次粗选浮选后、浮选粗精矿再经过两次精选,获得了Cu品位22.16%的铜精矿产品,同时Cu总回收率达到了92.72%,取得了较好的分选指标。

重组人尿激酶原联合硝普钠替罗非班冠状动脉内注射对高血栓负荷STEMI患者行PCI疗效的影响

目的 分析重组人尿激酶原联合硝普钠替罗非班冠状动脉内注射对高血栓负荷急性ST段抬高型心肌梗死(ST-segment Elevation Myocardial Infarction,STEMI)患者行经皮冠状动脉介入治疗(Percutaneous Coronary Intervention,PCI)疗效的影响。方法 选取2022年1月—2023年6月连云港市中医院收治的82例需行PCI高血栓负荷STEMI患者为研究对象,按照随机数表法分为研究组和对照组,各41例。对照组应用硝普钠、替罗非班冠状动脉内注射,研究组在对照组基础上给予重组人尿激酶原治疗,对比两组心功能指标、出血事件发生情况、术后并发症发生情况。结果 术后各时间点,研究组左心室舒张末期内径低于对照组,左心室射血分数高于对照组,差异有统计学意义(P均<0.05)。研究组并发症发生率(9.76%)低于对照组(26.83%),差异有统计学意义(χ^(2)=3.998,P<0.05)。两组出血率比较,差异无统计学意义(P>0.05)。结论 重组人尿激酶原联合硝普钠、替罗非班冠状动脉内注射,能够提高高血栓负荷STEMI患者行PCI过程中的心功能,降低术后并发症,且不会增加出血风险。

退役锂电池回收废液制备磷酸锂工艺研究

鉴于锂电池报废量大、锂含量高,探讨从退役锂电池回收废液中利用锂资源。根据溶液高钠含锂、碱含量高的特性,采用磷酸钠沉淀法回收锂,系统研究了反应过程中各工艺参数对磷酸锂回收率、纯度及粒度的影响。结果表明反应温度为102℃,磷酸钠1.1倍理论用量,磷酸钠浓度350 g·L^(-1),加料速率5 mL·min-1,搅拌速率500 r·min-1,冷水洗1 L时,磷酸锂收率能达到92.63%,纯度(质量分数,下同)达到98.81%,产品达到彩色荧光粉用磷酸锂行业标准二级要求。该工艺能广泛应用于各种高钠含锂溶液,特别是从锂浓度较低的溶液中回收锂资源,不仅解决了退役锂电池废液排放问题,还为锂资源提取提供了新途径。

High matrix metalloproteinase-9 expression induces angiogenesis and basement membrane degradation in stroke-prone spontaneously hypertensive rats after cerebral infarction

Basement membrane degradation and blood-brain barrier damage appear after cerebral infarc- tion, severely impacting neuronal and brain functioning; however, the underlying pathogenetic mechanisms remain poorly understood. In this study, we induced cerebral infarction in stroke- prone spontaneously hypertensive rats by intragastric administration of high-sodium water （1.3% NaC1） for 7 consecutive weeks. Immunohistochemical and immunofluorescence assays demonstrated that, compared with the non-infarcted contralateral hemisphere, stroke-prone spontaneously hypertensive rats on normal sodium intake and Wistar-Kyoto rats, matrix metalloproteinase-9 expression, the number of blood vessels with discontinuous collagen IV expression and microvessel density were significantly higher, and the number of continuous collagen IV-positive blood vessels was lower in the infarct border zones of stroke-prone sponta- neously hypertensive rats given high-sodium water. Linear correlation analysis showed matrix metalloproteinase-9 expression was positively correlated with the number of discontinuously collagen IV-labeled blood vessels and microvessel density in cerebral infarcts of stroke-prone spontaneously hypertensive rats. These results suggest that matrix metalloproteinase-9 upregula- tion is associated with increased regional angiogenesis and degradation of collagen IV, the major component of the basal lamina, in stroke-prone spontaneously hypertensive rats with high-sodi- um water-induced focal cerebral infarction.

铝酸钠溶液制备固体高纯铝酸钠实验研究

以铝酸钠水溶液为原料,通过蒸发-冷却析晶-脱水提纯工艺制备高纯固体铝酸钠,研究了添加剂对体系苛性比及析晶产物的影响以及铝酸钠溶液蒸发结晶过程的作用及行为。结果表明,以NaOH为添加剂能增加溶液体系苛性比,使蒸发结晶产物转变为NaAlO_(2);添加NaAlO_(2)晶种、以NaOH为添加剂调节体系苛性比至1.36,蒸发温度100℃、结晶时间2 h、搅拌速率300 r/min条件下,可获得纯度88.1%的铝酸钠产品;在脱水温度200℃、脱水时间1 h、乙醇100℃提纯1 h条件下,可得到纯度93.8%、晶体粒度5~25μm的固体高纯铝酸钠。

高钠饮食对我国居民1990—2019年胃癌疾病负担的影响及趋势分析

目的分析高钠饮食对我国胃癌疾病负担的影响情况,为胃癌高危人群防治策略优化提供参考。方法采用2019全球疾病负担研究(global burden of disease study 2019,GBD 2019)中的中国胃癌疾病负担数据,以Joinpoint回归模型分析1990—2019年我国高钠饮食所致胃癌死亡率和伤残调整生命年(disability‐adjusted life‐years,DALYs)的变化及其趋势,以平均年度变化百分比(average annual percent change,AAPC)和95%可信区间(confidence interval,CI)表示各相邻年份间构成比的变化量。结果我国高钠饮食所致胃癌死亡例数和粗死亡率自1990年的27226例(占我国胃癌总死亡例数8.913%)、2.300/10万上升至2019年的37131例(占我国胃癌总死亡数8.808%)、2.611/10万,但DALYs率从62.048/10万下降至61.434/10万。1990—2019年我国居民高钠饮食所致胃癌合计标化死亡率逐年下降1.716%,其中男性逐年下降1.221%,女性逐年下降2.661%(均P<0.001);标化DALYs率逐年下降2.005%,其中男性逐年下降1.495%,女性逐年下降3.067%。各年龄组DALYs率均呈下降趋势(均P<0.01),其中55~59岁居民的DALYs率下降速度最快(AAPC=-2.547%),80岁及以上居民的DALYs率下降速度较慢(AAPC=-0.702%)。我国居民高钠饮食所致胃癌标化DALYs率逐年下降(AAPC=-2.005%),下降速度高于中低和低社会人口指数(socio‐demographic index,SDI)国家或地区(AAPC=-1.209%、-1.119%),但低于全球以及高、中高、中SDI国家或地区的平均水平(AAPC=-2.094%、-3.166%、-2.361%、-2.090%)。结论我国居民高钠饮食所致的胃癌疾病负担逐年下降但水平仍较高,男性高于女性,老年男性人群是重点干预人群,应加强减盐饮食干预,以降低胃癌疾病负担。