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131.
钾长石粉酸浸除铁的实验研究 总被引:8,自引:1,他引:8
在利用钾长石粉合成沸石分子筛和制取碳酸钾技术中,铁的存在会降低沸石的白度。对北京平谷、天津蓟县、内蒙白云鄂博三地钾长石粉进行硫酸酸浸除铁实验,获得最大铁浸出率分别为88.6%、93.2%和64.6%,且前两地钾长石粉中铁的浸出行为相似,酸浸除铁效果均优于白云鄂博钾长石粉。采用正交实验法研究硫酸浓度、酸浸温度和时间对除铁效果的影响,表明三者对不同地区钾长石粉酸浸除铁效果的影响程度各不相同。钾长石酸浸除铁反应开始时,铁的溶解极快,反应速率主要由化学反应控制;其后溶解相对缓慢,反应速率则由扩散作用控制。 相似文献
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134.
Variations in chemical compositions of the eolian dust in Chinese Loess Plateau over the past 2.5 Ma and chemical weathering in the Asian inland 总被引:5,自引:0,他引:5
Major and trace elements as well as strontium isotopic composition have been analyzed on the acid-insoluble (AI) phase of
the loess-paleosol sequence from Luochuan, Shaanxi Province, China. Results show that the chemical composition of AI phase
of loess and paleosols is distinctive to the average composition of upper continental crust (UCC), characterized by depletion
of mobile elements Na, Ca and Sr. The distribution pattern of elements in AI phase reveals that initial dust, derived from
a vast area of Asian inland, has suffered from Na- and Ca-removed chemical weathering compared to UCC. Some geochemical parameters
(such as CIA values, Na/K, Rb/Sr and87Sr/86Sr ratios) display a regular variation and evolution, reflecting that the chemical weathering in the source region of loess
deposits has decreased gradually since 2.5 Ma with the general increase of global ice volume. This coincidence reflects that
the aridity of Asian inland since the Quaternary is a possible regional response to the global climate change. 相似文献
135.
Oliver Wild Oliver V. Rattigan Roderic L. Jones John A. Pyle R. Anthony Cox 《Journal of Atmospheric Chemistry》1996,25(2):167-199
The Cambridge 2-D Eulerian model has been used to study the potential atmospheric distributions and lifetimes of a number of CFC replacement compounds and their degradation products. The study has focused on HFC 134a and HCFCs 123, 141b and 142b and the major products formed by their atmospheric degradation. The loss of these compounds and their products by hydroxyl radical attack, photolysis and in-cloud hydrolysis have been investigated. The study has shown that HCFCs 141b and 142b have sufficiently long lifetimes to enter the stratosphere in significant quantities, where degradation leads to an increase in the total stratospheric chlorine concentration. The study has also highlighted areas where further experimental work would be valuable, in particular characterisation of the product channels for the degradation reactions and determination of the removal rates of the products in the aqueous phase. 相似文献
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Covariations in oceanic dimethyl sulfide,its oxidation products and rain acidity at Amsterdam Island in the Southern Indian Ocean 总被引:5,自引:0,他引:5
B. C. Nguyen N. Mihalopoulos J. P. Putaud A. Gaudry L. Gallet W. C. Keene J. N. Galloway 《Journal of Atmospheric Chemistry》1992,15(1):39-53
Simultaneous measurements of rain acidity and dimethyl sulfide (DMS) at the ocean surface and in the atmosphere were performed at Amsterdam Island over a 4 year period. During the last 2 years, measurements of sulfur dioxide (SO2) in the atmosphere and of methane sulfonic acid (MSA) and non-sea-salt-sulfate (nss-SO4
2-) in rainwater were also performed. Covariations are observed between the oceanic and atmospheric DMS concentrations, atmospheric SO2 concentrations, wet deposition of MSA, nss-SO4
2-, and rain acidity. A comparable summer to winter ratio of DMS and SO2 in the atmosphere and MSA in precipitation were also observed. From the chemical composition of precipitation we estimate that DMS oxidation products contribute approximately 40% of the rain acidity. If we consider the acidity in excess, then DMS oxidation products contribute about 55%. 相似文献
139.
研究了大孔膦酸树脂对毒砂中主、次和痕量元素的吸附行为及洗脱条件,结合巯基棉和TBP柱分离技术,建立了两个分离流程。在J-A1160型多道直读光谱仪上实现了毒砂单矿物中包括主量元素Fe和As在内的20个元素测定。主量元素As和Fe的相对标准偏差(n为5~10)分别为1.03%和0.9%,其它元素在5%~11%范围。流程经实际试样分析验证,结果与化学法相符。 相似文献
140.
8—氨基喹啉—5—偶氮—对苯甲酸的合成及应用—光度法测定痕量金 总被引:3,自引:1,他引:3
报道了新试剂8-氨基喹啉-5-偶氮-对苯甲酸(AQBA)的合成及分析应用。在阳离子表面活性剂CTMAB存在下,Au(Ⅲ)与AQBA在碱性介质中反应形成蓝绿色配合物,其最大吸收波长在608nm处,表观摩尔吸光系数为9.11×10~4L·mol~(-1)·cm(-1),Au量在0~1.8μg/ml范围内遵守比尔定律。所建立的新分析方法已应用于测定矿石及阳极泥中的痕量Au,结果满意。 相似文献