利用固相中镁含量和含水量研究光卤石分解转化

光卤石分解过程中的加水量决定着钾的转化率和收率,加水量可根据光卤石矿中的镁含量来计算.随着光卤石矿品位的变化,加水量应做相应的调整,一般通过分析分解固相和液相离子的组分来判断加水量是否合适,但是这种方法非常耗时.研究了不同加水量对光卤石分解固相中镁含量和含水量的影响,利用分解固相中镁含量与含水量的关系,确定光卤石的分解状况.结果表明:加水量过小,固相中镁含量与含水量呈非线性变化;加水量过大,固相中镁含量与含水量呈线性变化.这种利用分解固相中镁含量与含水量的关系来确定加水量是否适宜的方法简捷、快速、有效.     

磷矿氧化镁含量测定中异常现象的处理

通过试验 ,找出了磷矿石氧化镁含量测定中异常现象出现的原因 ,应注意 EGTA溶液计量的准确度。提出对氧化钙含量低的磷矿样 ,分析中应通过试验确定 EGTA溶液的加入量范围 ,以保证 Mg O测定的准确度     

Effect of magnesium content on structure and dielectric properties of cubic bismuth magnesium niobate pyrochlores

Structure and dielectric properties of cubic pyrochlore Bi_1.5Mg_NNb_2.5−NO_8.5−1.5N (BMN) compositions with N=0.6–1.3 have been studied. X-ray diffraction (XRD), infrared reflectivity spectra and Raman spectra were employed to analyze the crystal structures and phonon vibration modes of BMN compositions. The vibration spectra were sensitive to the content of Mg²⁺ ions, which is caused by the randomness of Mg²⁺ ions partially filling both the cubic pyrochlore A and B sites. The intensity of A3O stretching vibrations became stronger with increasing Mg²⁺ content, but B3O stretching vibrations were quite opposite. With the increase of Mg²⁺ content, the dielectric constant and loss tangent both increased. Temperature dependent dielectric constant was observed in the samples with N>0.8. The tendency of the dielectric constant with the increasing temperature showed a quick drop in the samples with higher Mg²⁺ content, which seems to be associated with the disorder in the A₂O′ network.     

率值及氧化镁含量对高镁熟料压蒸膨胀性能的影响研究

本文研究了MgO含量和熟料三率值对高镁熟料压蒸膨胀性的影响。81组高镁熟料结果显示：煅烧条件相同时,影响压蒸膨胀性的顺序为MgO含量﹥IM﹥KH﹥SM,MgO含量和IM是影响压蒸膨胀率的主要因素;采用岩相观测、XRD精修定量、BSE、EDS等微观测试对方镁石在熟料中的晶体生长环境和压蒸膨胀的关系进行了研究,发现方镁石被C₃A与C₄AF掺杂交错的中间相包裹时,压蒸膨胀率较低,当条状、板状C₃A相增加,掺杂交错的中间相减少,方镁石主要被C3A相包裹时,压蒸膨胀率增大。     

高镁磷矿化学脱镁过程的工艺研究

本文以磷矿硫酸脱镁为背景,选取马边磷矿为代表性矿样,通过正交实验设计及极差分析获得了该磷矿脱镁的实验室较佳工艺条件:即反应温度为55℃、pH值为3.0、磷矿初始粒度为150~180μm、液固比为2.0∶1、反应时间为2.0 h。同时对实验数据进行了回归分析,得到了磷矿脱镁后磷镁比的数学模型,该模型能较好地反映磷矿脱镁的宏观反应过程。在最优工艺条件下,可使该磷矿中镁脱除率达到68.42%,而磷的损失率仅为2.61%,处理后的磷矿接近HG/T 2673-1995湿法加工用磷矿II类标准。     

Effects of the content of silane coupling agent KH‐560 on the properties of LLDPE/magnesium hydroxide composites

Based on traditional idea of molecular coupling effect, surface modifiers were helpful to improve the performances of inorganic/organic composites. However, it was also widely accepted that the content of surface modifier should be controlled in a suitable range, and more or less modifiers could not reach to optimal properties. The intrinsic reason for this phenomenon was not clear until now. In this article, the influences of the content of surface modifier: silane coupling agent KH‐560, on the final performances of linear low‐density polyethylene (LLDPE)/magnesium hydroxide (MH) composites, have been studied. The performance tests of LLDPE/MH composites, including mechanical properties measurements, thermal oxidative stability analysis, and surface morphology observation, all confirmed that there was an optimal content range of surface modifier. However, further morphology investigation of the modified MH by particle size and particle size distribution analyzer showed that, the particle size and particle size distribution of MH both increased as the content of KH‐560 increased. ATR‐FTIR analysis proved that silane grafting was achieved on the MH particle surface, which not only improved the compatibility between MH and LLDPE for molecular coupling effect, but also caused bigger particle size and wider particle size distribution, which were disadvantageous to improve the performances of the composites. The two opposite effects of the surface modifiers mentioned above affected the final performances of the composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

不同粘结剂含量对金属喂料流动性能的影响

通过密炼机混炼出不同比例金属粉末与粘结剂的金属喂料,对不同粘结剂含量的金属喂料进行喂料流动性能对比实验,对比金属粉末含量对喂料熔融指数的影响及不同金属粉末含量在不同温度下表观粘度随剪切速率的变化,得到最佳注塑成型实验所用的最佳喂料配方。结果表明,随着粘结剂含量的增加,金属喂料的流动性能一直提高。在达到金属粉末质量分数92.6%之前,熔融指数急剧上升,当达到92.6%后,熔融指数缓步上升。     

工业硫酸镁标准中主含量测定方法的改进

原化工行业标准HG/T 2680-1995<工业七水硫酸镁>中硫酸镁主含量的测定方法存在缺陷,即分析结果数值偏高,与产品真实值存在偏差.根据存在的问题,在修订标准时提出了改进的设想,并进行了实验验证,给出了工业硫酸镁中硫酸镁主含量测定的准确分析方法,使测试结果更科学地反映产品质量的真实性.     

盐水中钙、镁离子含量的测定

建立了盐水中钙、镁离子的分析方法并进行详细描述，利用该方法对不同取样点的盐水进行测定，证明该检测方法简便、快速、准确，能够满足生产需要。通过大量的测定数据总结出规律，减少了分析次数，降低了生产成本，并找出保证正常生产的关键因素。     

Effects of hydrogen on the corrosion of pure magnesium

Electrochemical measurements and capacitance measurements were performed for better understanding of the effects of hydrogen on the corrosion of pure magnesium. Anodic polarization curves, activation energy (E_a), pitting initiation time and electrochemical noise (EN) were carried out, which showed that hydrogen had a strong influence on the corrosion of magnesium. There existed a highest corrosion resistance of magnesium, when a series of cathodic charging current density were applied to the specimens due to the optimum hydrogen concentration in the hydride coating (MgH₂) on the surface. Mott-Schottky results confirmed that there was a hydride coating on the charged magnesium. Hydrogen ionized as H⁻ and depleted donor/electron, which induced the inversion of semi-conductivity from N-type to P-type.     

利用氯化镁降低赤泥中碱含量的研究

用MgCl2溶液对赤泥进行处理,在加热和搅拌的条件下可以使赤泥中Na2O含量降低到0.13%。常温常压条件下用MgCl2溶液或人工海水处理赤泥,经浸泡也可以使赤泥中Na2O含量降低到0.8%以下,满足作为工业生产水泥原料的要求。     

Strength development in magnesium oxysulfate cement

Modulus of elasticity and microhardness measurements were made on magnesium oxysulfate systems (paste and compacted) having a wide range of porosity. Three sets of compacts were made; each set was made with particles having a different size range (5 to 150 μm; 150 to 300 μm; 300 to 600 μm). The log mechanical property versus porosity curves for paste samples were linear. The curves for compacted samples had a change in slope at 7.5 per cent porosity. At porosities less than 7.5 per cent, the data for paste and compacted samples were on the same curve. Tat higher porosities microhardness values for compacted samples were greater than those for paste samples; modulus of elasticity values were less. Compacted samples made with finest particles had higher values for mechanical properties at a given porosity. The mechanical behaviour of these systems was explained on the basis of the relative contribution of porosity, pore size distribution, interparticular bonds and strength of the solid phase.     

火焰原子吸收光度法测定铝合金中镁含量的研究

阐述了用原子吸收法测定铝合金中镁的含量,并对铝合金各种共存元素对镁的干扰进行了研究,发现通过控制酸度加入适当的基体改进剂,可以解决基体干扰问题,使测试误差在国标范围内,大大提高了分析效率,充分发挥了现代分析仪器的作用.     

络合滴定法测钙镁含量的研究综述

络合滴定法测定钙镁含量是采用络合反应滴定分析物质中的钙镁含量。本文对络合滴定法测钙镁含量影响因素及近几年络合滴定法在高钙低镁和高镁低钙体系测定钙镁含量的研究现状进行分析,以期对该方法的改进研究方向有所帮助。     

原子吸收法测定煤灰中镁含量的不确定度评定

通过对原子吸收法测定煤灰成分中镁含量的测量不确定度评定,对测量过程各分量建立了对应的数学模型,量化了各相对不确定度,并最终合成了标准不确定度和扩展不确定度。     

Effect of magnesium content on bioactivity of near invert phosphate-based glasses

A series of phosphate glasses 40P₂O₅-(40−x)CaO-xMgO-(20−y)Na₂O-yTiO₂ (where 0 ≤ x ≤ 24 and y = 0 or 1) with varying MgO contents were investigated for their in vitro calcium phosphate (CaP) formation. Thermal analysis of these glass compositions was conducted and a significant decrease in glass transition temperature from 448°C to 430°C was seen with reducing MgO content from 24 to 8 mol%. Degradation studies were performed in phosphate buffered saline (PBS) at 37°C, where the 8 mol% MgO glass showed the highest mass loss of around 3.4% after 28 days of immersion. Cation release studies were conducted via ion chromatography, using ultrapure water at 37°C as the degradation medium. The highest release of Ca²⁺ and Na⁺ ions was observed with the 8 mol% MgO glass. In vitro CaP formation studies were conducted using glass discs immersed in simulated body fluid (SBF) at 37°C for up to 28 days. The amorphous phase and chemical composition of deposited CaP layers on the glass discs were confirmed via X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) analysis, respectively. CaP layers with Ca/P ratio 0.8-1.1 were found to be deposited on the lower MgO content (8 to 2 mol%) glass surface after 28 days of SBF study.     

Electrochemical sensor for measuring magnesium content in molten aluminium

Design, construction, and tests of magnesium electrochemical sensors using molten salt electrolytes and pure magnesium metal reference are described. Alumina as well as magnesia membrane thimbles were synthesized to use as the supporting matrixes for the liquid electrolytes. Binary as well as ternary salt mixtures containing M9Cl₂ were impregnated in thimbles of various pore sizes. The accuracy, response time, and service life of the sensors were evaluated. The magnesium contents from the electromotive force (e.m.f.) measurements were comparable with those from the atomic absorption analysis. All sensors responded instantly to the changes of magnesium concentration in aluminium melt. The service life was between 2 to 6 h and the minimum initial equilibration time was 2 min, depending mainly on the pore size of the magnesia thimble and the electrolyte salt mixture in use.     

Effects of ethanol diets on cholesterol content and phospholipid acyl composition of rat hepatocytes

Chronic treatment of adult male rats with ethanol liquid diets resulted in alterations in phospholipid and cholesterol contents as well as the acyl composition of phosphatidylethanolamine (PE), phosphatidylinositol (PI)-phosphatidylserine (PS) mixture, and phosphatidylcholine (PC) of isolated hepatocytes. The influence of ethanol on these lipids was largely dependent on the proportion of dietary fat. Phospholipid and total cholesterol contents were elevated 23 and 27%, respectively, by ethanol when offered in a low-fat diet (5% corn oil). Only the percentage of arachidonic acid from PI-PS was significantly reduced in the low-fat ethanol group. Exposure to a high-fat (34% corn oil) diet in the presence of ethanol for 4–5 weeks resulted in a significant decrease in arachidonate/linoleate ratios of hepatic PE, PS-PI and PC, while total phospholipid content remained constant. In the high-fat, ethanol-treated group, hepatic cholesterol content was increased 2-fold. These results suggest that the level of dietary fat plays an important role in determining the effects of chronic ethanol consumption on hepatic cholesterol content and phospholipid acyl composition.     

中国镁资源优势及镁质化工材料发展方向

镁质化工材料属于镁质材料的一种，包括镁盐中各类产品，广泛应用于国民经济中的各个领域。其原料来源广，储量丰富，主要包括含镁非金属矿、海水、卤水、盐湖苦卤，以及化工、冶金、轻工等行业副产物，可通过机械加工法或化学加工法制取不同规格、不同类型的镁质化工材料。重点介绍了活性氧化镁、电工级氧化镁、硅钢级氧化镁、高纯氧化镁等开发与生产现状；分析了中国具有丰富的镁资源和能源、多种工艺路线生产镁质化工材料，以及精细镁产品发展迅速的优势，建议建立万吨级骨干企业，发挥原料及生产方法多样、镁产品品种齐全的优势，采用先进设备，提升自控水平和精细化率，满足国内外市场的需求。     

Effects of different Mg fertilizer sources on the magnesium availability in soils

Pot experiments with different soils were conducted to determine the effect of different Mg fertilizer sources on magnesium availability. The sources studied included Kieserite (MgSO₄ H₂O), a synthetic magnesium sulphate (SMS) with variable content of crystal water and a calcined magnesite (Mg-oxide). The three magnesium fertilizers vary greatly in their solubility in water, affecting the availability to plants once applied to the soil. Whereas Kieserite dissolved gradually and SMS immediately, Mg-oxide released only insignificant amounts of Mg in cool water (20?°C) after intensive stirring. Due to the fact that these dissolution properties may distinctly affect Mg availability in soils, Kieserite as a standard magnesium source was tested against a slow release Mg-oxide in the fine and the coarse form. Soil extraction of samples taken from 0–10 and 10–20 cm depths at 4, 8 and 12 weeks after applying the fertilizers to the soil surface revealed that the rate at which Mg appeared in the available pool (CaCl₂ extracts) varied significantly between Mg sources. Mg availability from Kieserite was much greater than from Mg-oxide. Nutrient availability from Mg-oxide depended on the fineness of the material, i.e. the coarser the less available. Maize grown as test plant in the pots revealed a 10.6% larger yield and 19.6% larger Mg uptake in Kieserite than in Mg-oxide treated pots. High solubility of a fertilizer under high rainfall conditions, however, may also affect the Mg availability through large losses occurring by Mg leaching. Therefore, in a second experiment, the behaviour of surface applied magnesium fertilizers, Kieserite versus a quickly dissolving synthetic magnesium sulphate (SMS) was studied, using an Ultisol (Serdang Series soil from Malaysia). A simulation of high rainfall by excessive irrigation of 20 mm per day over a period of 16 days to a water saturated soil revealed that the amount of Mg lost by leaching differed between the two Mg sources tested. The lowest amount with 8.7% of the applied Mg was lost in the Kieserite treatment at the low application rate and the highest with 22.3% in the SMS treatment at the high application rate. It is concluded that a gradual but strong release to match plants requirements is the most desired characteristic to maximize crop uptake and minimize losses.