Effect of Calcium on the Vanadium Extraction from High Calcium Type Stone Coal

The high calcium type stone coal from Hubei province was leached by water and dilute acid separately after being roasted with different dosage of Na Cl. The water leaching rate of vanadium（WLRV） was low and only 26.8% of vanadium can be leached by water when 4% Na Cl was added, but the acid leaching rate of vanadium（ALRV） was relatively high. Calcium in the high calcium type stone coal is greatly superfl uous relative to vanadium, hence, the calcium reacts with vanadium to form Ca（VO3）2, Ca2V2O7 and Ca3（VO4）2orderly during the stone coal roasting process and high temperature is beneficial to the reactions between calcium and vanadium, which was validated by simulated reactions between pure calcium carbonate and vanadium pentoxide. These calcium vanadates are all water insoluble but acid soluble and this causes the low WLRV and relatively high ALRV. After calcium removal by HCl, the WLRV is highly enhanced and reaches about 50% when only 2% Na Cl was added. If the HCl content is too high, the stone coal is easily sintered and the formed glass structure can enwrap vanadium, which leads the WLRV to decline. Single water leaching process is not appropriate to extract vanadium from high calcium type stone coal.

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.

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.

Research on Preparation and Influencing Fctors of High Calcium High Sulfate Ash to Autoclaved Aerated Concrete

In this paper, a high calcium high sulfate ash as the main material, adding fly ash, lime, cement, gypsum and some modifiers to prepare autoclaved aerated concrete. The products complies with the technical requirements of GB/T11968-2006. This paper also studies the influence of the physical methods and water ratio on autoclaved aerated concrete by high calcium high sulfate ash aerated concrete. The best ratio of water and Grinding time were found in practice study.

Effect of Calcium Oxide Additive on the Performance of Iron Oxide Sorbent for High-Temperature Coal Gas Desulfurization

The effect of calcium oxide additive in iron oxide sorbent for hot gas desulfurization was investigated by XRD and TPR techniques.XRD characterization showed that CaO was highly dispersed after the calcination of sorbents.Calcium sulfate formed in the desulfurization was decomposed and regenerated to CaO by reacting with CO before the next sulfidation process.Calcium participated in every sulfidation/regeneration cycle and contributed to the enhancement of sulfur capacity.The TPR results showed that the reduction temperature of the sorbent increased with the increase of the content of calcium.Calcium played a role of retarding reduction.Therefore,the addition of calcium oxide additive will benefit the utilization of iron oxide sorbent in strongly reducing atmospheres.

X-ray diffraction investigation of amorphous calcium phosphate and hydroxyapatite under ultra-high hydrostatic pressure

The changes in the crystal structures of synthetically prepared amorphous calcium phosphate（ACP） and hydroxyapatite（HAP） in water（1：1 mass ratio） were studied by synchrotron X-ray diffraction（XRD） under ultra-high hydrostatic pressures as high as 2.34 GPa for ACP and 4 GPa for HAP. At ambient pressure, the XRD patterns of the ACP and HAP samples in capillary tubes and their environmental scanning electron micrographs indicated amorphous and crystalline characteristics for ACP and HAP, respectively. At pressures greater than 0.25 GPa, an additional broad peak was observed in the XRD pattern of the ACP phase, indicating a partial phase transition from an amorphous phase to a new high-pressure amorphous phase. The peak areas and positions of the ACP phase, as obtained through fitting of the experimental data, indicated that the ACP exhibited increased pseudo-crystalline behavior at pressures greater than 0.96 GPa. Conversely, no structural changes were observed for the HAP phase up to the highest applied pressure of 4 GPa. For HAP, a unit-cell reduction during compression was evidenced by a reduction in both refined lattice parameters a and c. Both ACP and HAP reverted to their original structures when the pressure was fully released to ambient pressure.

EFFECT OF ADDED DIETARY CALCIUM ON ESOPHAGEAL EPITHELIAL-CELL PROLIFERATION IN SUBJECTS AT HIGH RISK FOR ESOPHAGEAL CANCER: A DOUBLE-BLIND INTER-VENTION STUDY

A randomized double-blind intervention trial was carried determine whether oral calcium supplementation could lower the proliferation of epithelial cells of the esophagus. 41 subjects identified with precancerous lesions by histopathology were randomized to receive oral supplementation of their conventional diets with 0.6 g of calcium as calcium carbonate or placebo. Both at the entry to the study and at the end of the treatment, seven months later, the subjects were examined, with an emphasis on the frequency and distribution of proliferating epithelial cells of the esophagus. Patterns of cell proliferation was defined by dividing the esophageal epithelium into cell columns oriented perpendicularly to the basal cell layer and by comparing the numbers and fractions of tritiated thymidine-labeled epithelial cells in the various cell columns and cell compartments.Before dietary supplementation with calcium, the profile of proliferating epithelial cells in the esophageal compartments in calcium group is similar to that in the placebo group, which is comparable to that previously observed in subjects with high risk for esophageal cancer. Seven months after supplementation having been started, in calcium group, proliferation was significantly reduced and the profile of the esophageal columns approached to that previously observed in subjects at low risk for esophageal cancer, however, in the placebo group, the proliferation and profile maintain at the same level as that before supplementation. Our findings indicate that oral calcium supplementation induces a more quiescent equilibrium in epithelial-cell proliferation in the esophageal mucosa of the subjects at high-risk for esophageal cancer, similar to that observed in subjects at low risk.

从高钙富硼老卤中提硼研究

以青海某高钙富硼老卤为研究对象开展了提硼研究。结果表明,合适的萃取条件为:磺化煤油为稀释剂、异辛醇用量50%、萃取相比1.0、萃取混合时间15 min;合适的反萃条件为:反萃剂为pH=1的稀盐酸、反萃相比1.5、反萃混合时间15 min。以此条件在5级混合澄清槽中完成了连续逆流萃取—反萃运转试验,连续运转45 h,硼萃取率为95.49%,硼与钾、钠、钙、镁的分离效果较好;硼反萃率为99.59%,反萃液中硼含量达17.17 g/L。采用“溶剂萃取—反萃—高温蒸发—低温冷却结晶—重溶—冷却结晶—过滤洗涤—干燥”工艺高效分离提取硼,硼总回收率为92.33%,制备出的硼酸产品达国家标准(GB/T 538—2018)要求。

Relationship between coronary calcium score and high-risk plaque/significant stenosis

AIM To investigate the relationship between coronary calcium score(CCS) and vulnerable plaque/significant stenosis using coronary computed tomographic angiography(CCTA). METHODS CCTA was performed in 651 patients and these patients were divided into the four groups(CCS 0, 1-100, 101-400 and > 400). We studied the incidence of high-risk plaque, including positive remodeling, low attenuation plaque, spotty calcification, and napkin-ring sign, and significant stenosis in each group. RESULTS High-risk plaque was found in 1.3%, 10.1%, 13.3% and 13.4% of patients with CCS 0, 1-100, 101-400 and > 400, respectively(P < 0.001). The difference was only significant for patients with zero CCS. The incidence of significant stenosis was 0.6%, 7.6%, 13.3% and 26.9% for each patient group, respectively(P < 0.001), which represented a significant stepwise increase as CCS increased. The combined incidence of high-risk plaque and significant stenosis was 1.9%, 17.7%, 26.9% and 40.3% in each patient group, respectively(P < 0.001), again representing a significant stepwise increase with CCS. The rate of major coronary event was 0%, 4.0%, 7.9% and 17.2% in each patient group, respectively(P < 0.001), another significant stepwise increase as CCS increased. CONCLUSION Stepwise increased risk of coronary events associated with increasing CCS is caused by increasing incidence of significant stenosis, while that of high-risk plaque remains the same.

喷吹神东高钙烟煤对高炉回旋区热状态的影响

高炉风口和回旋区的热状态对炉内煤气流的一次分布具有重要影响,进而影响高炉的经济技术指标。为探究喷吹神东高钙烟煤对高炉回旋区热状态的影响,本文通过收集某钢铁企业试烧期间高炉鼓风参数及其他各项操作参数,采用Fluent仿真模拟方法,建立风口回旋区的三维燃烧模型,系统分析不同喷吹条件下温度分布、气体分布、速度分布的变化规律,从而确定在风口复杂条件下喷吹神东高钙烟煤对高炉回旋区热状态的影响。模拟计算结果表明:神东高钙烟煤和ES无烟煤燃烧后产生的还原气体量最多,生产时有利于矿石的还原;向高炉喷吹神东高钙烟煤、HX烟煤、WN烟煤、SG烟煤与ES无烟煤混合煤粉时,燃尽率分别为72.25%、70.11%、68.87%、67.56%,神东高钙烟煤与ES无烟煤混合喷吹时煤粉的燃尽率最高,这是由于神东高钙烟煤和ES无烟煤的CaO质量分数较高,其在风口、回旋区内的燃烧特性最佳;混合喷吹神东高钙烟煤与ES无烟煤时,风口、回旋区内的煤气成分和煤粉燃尽率等方面要强于其他三种情况,适宜向高炉喷吹。

高钙铁尾矿对多孔陶瓷烧结温度和性能的影响

为促进矿业固废铁尾矿的高值化利用,以高钙铁尾矿作为主要原料,高岭土为黏结剂,石英作为骨料,碳化硅为发泡剂,采用“注浆成型-直接发泡法”制备高孔隙率铁尾矿多孔陶瓷,并通过测试多孔陶瓷孔隙率、孔径分布、体积密度和抗压强度,研究铁尾矿用量对多孔陶瓷烧结温度及性能结构的影响。结果表明,高钙铁尾矿可作为助熔剂使用,在原料配比为40%铁尾矿,20%高岭土、40%石英,外加0.3%碳化硅,烧结温度在1160~1170℃的条件下所制备的多孔陶瓷各项性能最优,其体积密度密度为0.38~0.46 g/cm^(3),气孔率高达80.84%~83.5%,平均孔径为0.33~0.88 mm,抗压强度为1.95~3.28 MPa。微观分析表明,铁尾矿内的方解石高温下分解产生的CaO可以与原料中的SiO_(2)反应生成钙长石,并大幅度降低材料的烧结温度和液相黏度,同时铁尾矿中的方解石和Fe_(2)O_(3)可以促进气泡的增长,有利于进一步提高气孔率。

高钙高锂型卤水制碳酸锂钙镁离子脱除工艺研究

对高钙、高锂、低镁锂比(Mg/Li=0.02)国外阿根廷某盐湖卤水进行钙、镁、锂深度分离的工艺研究。采用两步法去除溶液中的Ca^(2+)、Mg^(2+):首先加入硫酸钠生成硫酸钙沉淀除去大量的Ca^(2+),后加入氢氧化钠形成氢氧化镁和氢氧化钙除去少量的Ca^(2+)、Mg^(2+);分别考察了物料比、反应温度、加料时间、加料速率、pH值对卤水除杂效果的影响因素。结果表明:在反应温度60℃、硫酸钠用量为1.3、加料速率6 mL/min、反应时间70 min条件下,溶液中Ca^(2+)的脱除率为96.22%,Li+的损失率为1.44%;在pH值为14、10 mol/L NaOH、反应时间50 min、反应温度50℃、加料速率为8 mL/min条件下,最终溶液中Ca^(2+)脱除率为99.75%,Mg^(2+)去除率为100%,Li+的损失率为0.04%;实现了钙镁离子的深度去除,为后续工序制备碳酸锂创造了有利的条件。

CO_(2)矿化改性高钙粉煤灰对水泥砂浆力学性能和微结构的影响

为改善高钙粉煤灰在混凝土中的体积安定性和水化活性,本文对高钙粉煤灰进行了CO_(2)矿化改性,研究了不同CO_(2)矿化反应时长下高钙粉煤灰的固碳量和游离氧化钙含量,及CO_(2)矿化改性高钙粉煤灰对水泥砂浆水化热、力学性能和孔隙结构的影响。结果表明,经12 h CO_(2)矿化改性处理,高钙粉煤灰固碳量可超过10%(质量分数),高钙粉煤灰中的游离氧化钙含量明显降低。随着矿化反应时间的延长,掺高钙粉煤灰的水泥浆体水化诱导期缩短,早期水化放热量明显降低。CO_(2)矿化改性处理还能减轻高钙粉煤灰对水泥砂浆强度的负面影响,改善水泥砂浆孔隙结构,降低孔隙率和大孔含量,促进水泥的早期水化和水化硅酸钙的成核结晶。

镁铝水滑石对高铁低钙硅酸盐水泥性能的影响

采用成核晶化隔离法合成了镁铝水滑石(MgAl-LDH),并利用石灰石、砂岩和铁矿粉制备了高铁低钙硅酸盐水泥熟料(铁相质量分数为19.6%)。通过X射线衍射(XRD)、热重(TG)、扫描电镜(SEM)和化学分析法,研究了MgAl-LDH掺量对高铁低钙水泥氯离子固化能力、力学性能和微观结构的影响规律。结果表明:MgAl-LDH能显著提升高铁低钙水泥化学固化氯离子能力及力学性能;当MgAl-LDH掺量为3%(质量分数)时,与空白组相比,7 d氯离子固化率提升了46.4%,3、7、28 d抗压强度分别提高了27.5%、34.6%和17.1%。微观测试表明MgAl-LDH能促进高铁低钙水泥早期水化生成更多的水化产物,在一定程度上促进了水泥结构的致密化;并且能促进水化产物和氯离子发生反应生成Friedel′s盐,提升了高铁低钙水泥对氯离子的化学固化量。

利用含锌工业固废制备高纯氧化锌的工艺研究

针对氧化锌尾矿和废弃水渣等工业固废中有价锌难以回收的问题,以当地工业含锌固废为原料,利用碳热还原氧化法,制备了高纯氧化锌微粉。通过HSC Chemistry进行热力学计算和试验研究结合的方式,分析了含锌废渣中硅酸锌与碳还原反应的热力学过程。讨论了配碳量、焙烧温度、焙烧时间以及CaF_(2)对硅酸锌还原过程锌产率的影响。结果表明,在以CaF_(2)为催化剂时,1000~1100℃催化效果最显著。得出最佳工艺条件:在温度为1100℃、保温时间40 min、碳含量20 wt%、CaF_(2)添加5 wt%的条件下锌产率(氧化锌回收率)为97.44%。对挥发产物进行结构和成分分析,其物相为六方纤锌矿结构的氧化锌晶体,粒度大小2~4μm,纯度达到了99.47%。

碳酸钙为发泡剂的粉煤灰发泡陶瓷制备

发泡陶瓷作为一种新型建筑墙体材料,具有轻质保温的特性.以粉煤灰为主要原料,分别添加碳酸钙、四硼酸钠作为发泡剂和助熔剂,通过球磨、压片、烧制等工艺实现了一种新型发泡陶瓷的制备,同时研究了烧结温度、发泡剂掺量、粉煤灰添加量以及粉料粒度对发泡效果的影响.结果表明,样品平均孔径会随发泡剂掺量增加而增大;随烧结温度升高,样品的表观密度先下降后上升,孔隙率与之呈相反趋势,平均孔径会逐渐升高;样品的表观密度和孔隙率随粉料粒度的降低而降低,抗压强度则会提升.研究表明,在发泡剂掺量为1%、烧结温度为750℃、保温时间为15 min的工艺下可制得表观密度为0.156 g/cm^(3)、孔隙率为93%、抗压强度为2.23 MPa的发泡陶瓷.

利用石灰石制备高活性石灰的试验研究

活性高的石灰对节能减排以及“碳达峰、碳中和”具有重要作用,但是目前的活性石灰已经难以满足要求,高活性石灰生产技术越来越受到重视。本文针对乌海包钢矿业公司海南矿石灰石,分析了原料特性,研究了制备高活性石灰的工艺技术。研究结果表明:该矿业公司的石灰石主要矿物为方解石、白云石、石英、铁矿物,其分解特性与粒度有较大关系;利用该种石灰石可以煅烧高活性石灰,其最优条件为:粒度0.125~0.63mm,煅烧温度1000~1050℃,煅烧时间30~40 min。该条件下煅烧的高活性石灰晶粒细小,孔隙多,活性高。

钙基脱氯剂脱除重整高温烟气中HCl的研究

重整催化剂的再生过程主要为:卸料、烧焦、氧氯化、焙烧、冷却、隔离等步骤,其中烧焦和氧氯化为关键步骤。重整催化剂运行一定时间因表面积碳结焦而失活,“烧焦”是在氧气存在和高温条件下将催化剂上的积碳转化为二氧化碳,随着循环气带走,此过程中也伴随着催化剂上的关键组分氯的脱附,并以氯化氢的形式存在于循环气中。钙系脱氯剂使用精度高,脱氯效果好,在市场上广泛应用。实验以氢氧化钙和碳酸钙为主要活性组分,辅助加入其他提高脱氯效果的金属元素,增加金属直接协同作用,达到提高脱氯效果的目的。采用滚球成型的方式,对脱氯剂进行成型,可以有效保护活性组分的孔结构,通过脱氯评价对实验结果验证,使用后样品的氯含量可达36%以上。

脉冲电脱盐在高钙原油预处理中的应用

通过对脉冲电场强度、占空比、脉冲频率、电脱盐温度和停留时间等因素的考察,进行了脉冲电脱盐对钙离子含量高达1800μg/g的新疆高钙原油的预处理研究,并与常规电脱盐技术进行的对比试验。研究结果表明,采用脉冲电脱盐工艺经3级电脱盐后净化油盐含量、净化油含水、净化油含钙均达到了常规电脱盐4级后的预处理效果,脉冲电脱盐技术对高钙原油具有良好的电脱盐预处理效果。

荷丹胶囊联合阿托伐他汀钙对老年高血压合并高脂血症患者血脂、炎症因子的影响

目的探究荷丹胶囊联合阿托伐他汀钙对老年高血压合并高脂血症患者的治疗效果。方法选取2019年10月至2021年9月江西医学高等专科学校第一附属医院收治的92例老年高血压合并高脂血症患者为研究对象,按照计算机随机数字表法分为照组和观察组,每组46例。对照组行阿托伐他汀钙治疗,观察组则在对照组的基础上加用荷丹胶囊治疗。比较两组的临床疗效、血脂与炎症因子水平变化和不良反应情况。结果观察组总有效率高于对照组,且不良反应发生率低于对照组,差异有统计学意义(P<0.05)。治疗前,两组的血脂指标水平与炎症因子水平比较,差异无统计学意义(P>0.05)。治疗后,观察组的高密度脂蛋白胆固醇(HDL-C)高于对照组,总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、超敏C反应蛋白(hs-CRP)、白细胞介素-1(IL-1)、白细胞介素-6(IL-6)均低于对照组,差异有统计学意义(P<0.05)。结论荷丹胶囊联合阿托伐他汀钙治疗老年高血压合并高脂血症患者,能有效缓解患者炎症因子水平和降低血脂水平,且可提高临床疗效和安全性,具有良好的应用价值,值得临床推广。