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1.
采用高压水热活化法对预先烧制的粉煤灰进行碱溶实验,探讨钙硅摩尔比、碱液浓度、液固比、苛性比、反应温度、反应时间等影响因素对于氧化铝溶出率的影响。考虑到氧化铝溶出率及反应成本等各方面因素,得出氧化铝溶出的适宜条件。结果表明:碱溶条件下,钙硅摩尔比为1.0,溶液碱浓度为350 g/L,液固比为10∶1,苛性比为14,反应温度280℃,活化时间为2 h。通过氧化铝溶出工艺条件的优化,可使氧化铝提取率达到95%以上。 相似文献
2.
较低的矿物溶解率和反应剂的不可循环利用是CO2矿物封存发展的两大难题。针对这些问题,本文提出了一种新的以可循环的NH4Cl溶液作为中间媒介的CO2矿物封存工艺,并系统地研究了蛇纹石在氯化铵溶液中的液-固两相的反应动力学。实验研究发现:(1)纤蛇纹石的浸取符合Elovich模型,浸取过程基本在1h左右完成,在100℃、5mol/L氯化铵溶液中,纤蛇纹石的浸取率达到12.67%;(2)温度对纤蛇纹石初始反应速率的影响显著,温度越高,反应速率越快;(3)当氯化铵浓度在1~5mol/L范围内变化时,它对镁离子浸取率的影响不明显,反应速率随着浓度的升高而有所增加;(4)本实验反应表现出来的活化能大小为129.56kJ/mol。 相似文献
3.
《矿物学报》2013,(Z1)
The flake-like basic magnesium carbonate was prepared from the ammonium sulfate leaching liquid of asbestos tailings. The method of X-ray diffraction, Fourier transform infrared spectra, TA-DTG and SEM analysis had been used to research the influence of the reaction temperature on the phase, structure and morphology of the product during the preparation of the basic magnesium carbonate. The results indicates that the product was needle-like magnesium carbonate hydrate at the lower reaction temperature (from 35 ℃ to 65℃), with the increase of the reaction temperature (75 ℃ to 95 ℃ ), the needle-like magnesium carbonate hydrate (MgCO3·xH2O) transformed to flake-like basic magnesium carbonate [Mg5(CO3)4(OH)2·4H2O], the reaction temperature plays an important role in the preparation of flake-like basic magnesium carbonate, the preparation of flake-like basic magnesium carbonate was a nucleation-dissolution-recrystallization growth mechanism process. 相似文献
4.
Based on the requirement of the new technology for producing potassium sulfate and N-Mg compound fertilizer,boussingaultite,by the reaction of the mineral shoenite from Kunteyi Salt Lake,Qinghai province,and the industrial byproduct ammonium sulfate,the solubilities of the quaternary system (NH_4)_2SO_4-Mg SO_4-K_2SO_4-H_2O at 25.0oC in the isothermal evaporation and crystallization process were measured using the isothermal evaporation method,and the corresponding phase diagrams were plotted.According to the diagram,this system contains six saturation points and six solid phase fields of crystallization,which correspond to (K_(1-m),(NH_4)_m)_2SO_4,(NH_4)_2SO_4·Mg SO_4·6H_2O,K_2SO_4·Mg SO_4·6H_2O,Mg SO_4·6H_2O,(K_(1-n),(NH_4)_n)_2SO_4·Mg SO_4·6H_2O and Mg SO_4·7H_2O,respectively.By analyzing and calculating the isothermal evaporation and dissolution phase diagram of this quaternary system at 25.0oC,K_2SO_4 and (NH_4)_2SO_4·Mg SO_4·6H_2O can be separated via K_2SO_4·Mg SO_4·6H_2O and (NH_4)_2SO_4 as raw materials.Theoretical calculations about the proposed process were carried out and verified by experiment,which indicated that the yield of potassium sulfate was improved and the magnesium resources were fully utilized. 相似文献
5.
煤的结渣特性是动力用煤的主要指标,也是燃煤锅炉设计过程中的重要参数,煤灰中化学成分对煤灰熔融性和结渣性影响较大,尤其是SiO2、Al2O3、Fe2O3、CaO等主要成分的含量和组成。基于元屯沟井田三叠系瓦窑堡组煤的煤灰成分、煤灰熔融性试验数据分析,发现该区煤层中SiO2+Al2O3含量大于80%,Fe2O3+CaO小于10%,煤灰属较高灰煤灰软化温度。通过对煤灰软化温度、硅铝比、酸碱比、铁钙比、结渣指数以及综合结渣指数等多个指标的分析,得出煤灰属轻微结渣性。 相似文献
6.
Leaching studies of low-grade pyrolusite, containing 11.84% Mn with high silicon, were carried out using sodium sulfite as a reductant in ammonium sulfate medium. Various process parameters including temperature, leaching time, solid-liquid ratio, quantity of ammonium sulfate, as well as the amount of reducing agent were studied in detail. The manganese extraction yield was the response of the process. Temperature and reagent concentration exerted the most important positive effect on the manganese extraction. The optimized conditions showed that when the amount of reducing agent was a stoichonmetric amount, over 90% manganese extraction and the lowest impurities were achieved, the amount of heavy metal impurities in the manganese leaching liquid was less than 5 mg/L, and almost no iron and aluminum were extracted in 3 mol/L ammonium sulfate concentration at 100 ℃ in 45 min. 相似文献
7.
DS1试样主要化学成分为Al2O3 64.31%,SiO2 8.92%,A/S 7.11,TS 0.30%;该试样经焙烧-湿法预脱硅处理后,A/S由7.11提高到26.37,Al2O3由63.41%升高到78.53%,TS从0.30%降低到0.11%;焙砂在温度280℃,时间60 min,配料比αk 1.45,碱浓度为220 g/l,石灰添加量4%的最佳溶出条件下,Al2O3的绝对溶出率为95.52%,相对溶出率99.59%;Ga的溶出率91.63%,溶出物在1100℃下锻烧2 h,可获得Al2O3>99%,其他各项指标均优于YS/T274-1998AO-1行业标准的氧化铝产品。 相似文献
8.
Determining Biogenic Silica in Marine Samples by Tracking Silicate and Aluminium Concentrations in Alkaline Leaching Solutions 总被引：5，自引：0，他引：5
This study introduces an alkaline leaching technique for the simultaneous analysis of biogenic silica and aluminium in sediments. Measuring aluminium facilitates the discrimination between silica from the biogenic (BSiO2) and the non-biogenic fraction, because it originates almost solely from the lithogenic phase. The method was tested using fine-grained silicagel, standard clay minerals, artificial sediments, and natural samples ranging from fresh diatoms to aged sediment from different depositional settings. To determine the BSiO2 content, four different models each describing the dissolution curves, but of increasing complexity, were applied and for each different type of sample the optimum model was selected on the basis of F-test statistics. For mixtures of silicagel and clay minerals, the contribution of Si from the dissolution of clay was negligible compared to Si originating from silicagel. For natural samples with high clay content, complex dissolution curves were observed and single-phase first order dissolution was the exception. This deviation from `ideal' behavior could only be recognized because of high-resolution sampling, especially in the first 20 minutes of the experiment. For most of the samples, the distinction between the biogenic silica fraction and the silica originating from dissolution of clays could be made on the basis of the Si/Al ratios and reactivity constants of the dissolving phases calculated with the models. Clay minerals typically dissolve slowly at a Si/Al ratio close to 1–2, depending on the type of clay mineral. In contrast, biogenic silica displays a wide range of reactivities and Si/Al ratios. Fresh biogenic silica from the water column usually has a high reactivity and a low Al content. Aged biogenic silica from the sediments has a lower reactivity, but Si/Al ratios as low as 5 were found. The method as described here therefore presents an accurate method to analyze biogenic silica in marine sediments with a relatively high clay mineral content. 相似文献
9.
湘江铀矿产于湖南某地二迭系岩层中一铀矿床的氧化带中。对该铀矿床的成因目前有两种看法,一种认为是沉积变质型;另一种认为是沉积迭加热液型。湘江铀矿呈浅黄色的粉末状微晶集合体产于硅质岩的裂隙内或风化孔洞中。与铝铀云母,黄铁矿,石英,磷铝石等矿物共生。根据产地命名为湘江铀矿。 相似文献
10.
霞石正长岩烧结反应的热力学分析与实验 总被引：2，自引：2，他引：0
霞石正长岩是一种富含K2O、Al2O3、SiO2的矿产资源。在综合分析云南个旧白云山霞石正长岩物相组成的基础上,对以Na2CO3为助剂中温分解霞石正长岩中的铝硅酸盐矿物,提取碳酸钾和氧化铝的技术路线进行了研究。根据热力学理论计算以Na2CO3为助剂,主要烧结产物为NaAlSiO4、KAlSiO4、Na2SiO3时的反应温度,结果表明理论上反应在800 K(527 ℃)左右开始发生。通过烧结反应实验,得到优化反应温度为800～850 ℃,霞石正长岩的分解率达95%以上。X射线衍射分析结果表明,烧结产物的主要物相为NaAlSiO4、KAlSiO4和Na2SiO3,与热力学计算结果一致。烧结产物的硫酸酸浸实验表明,硅铝分离效果良好,SiO2、Al2O3、K2O三者的提取率分别高达91.4%、92.2%、92.5%。与前苏联的石灰石烧结法相比,本工艺具有低能耗、低物耗和生产过程清洁高效等优点。 相似文献
11.
《矿物学报》2013,(Z1)
The potassium-feldspar can be decomposed using the KOH as additive via hydrothermal synthesis methods, which can destroy the structure of the potassium-feldspar and turns its K+ into water soluble potash resources and make its silica component utilized. The potassium-feldspar from Inner Mogolia was decomposed after iron removing and hydrothermal processes successively. The results showed(Table 1) that the iron could be removed up to 98.56% after the treatment of 90℃ for 2 hours with 5.8mol/L density of HCL solution. It is seen from the Table 1that the content of iron significantly decreased while the content of SiO2, Al2O3, K2O increase. The treated sample was used to be decomposed by hydrothermal method in KOH solution. The results showed that the dissolution rate of SiO2 could be up to 64.73% after the hydrothermal treatment of 260 ℃ for 2 hours with 1.2 mol/L density of KOH(Fig 1). The solid product is mailnly kalsilite phase. 相似文献
12.
一般特点及物理性质龙门山拗陷中段是一个很有意义的泥盆纪沉积磷矿的成矿区。在成矿区的西侧,含磷岩系的岩性序列自下而上为:角砾状和致密块状磷块岩、磷铝质岩、黑色页岩和细砂岩。在磷铝质岩中,有时在磷块岩层上部,产有一种沉积岩中罕见的自生矿物--磷锶铝石的合硫和钙的变种。该矿物首先由段前烈、舒銮绶等同志发现,定名为硫磷铝锶矿,并认为与其变种羟硫磷铝锶矿相当。磷铝质岩呈灰色、晤灰色及灰黑色,有时带咖啡色,中厚层至厚层状(照片1),主要组成矿物是磷锶铝石及粘土矿物(以高岭石为主,有少量水云母),此外尚有磷灰石、黄铁矿、有机质,以及陆源碎屑矿物:电气石、锆石、金红石、磁铁矿、钛磁铁矿等。磷铝质岩成似层状或透镜状产出,沿走向方向在该区南北两端相变为硅质岩。 相似文献
13.
硫酸根离子对方解石和白云石溶解度的影响 总被引：9，自引：3，他引：6
在无CO2和有PCO2条件下,利用目前成熟的水文地球化学模拟软件——PHREEQC,分别对方解石、白云石在Na2SO4、CaSO4和MgSO4溶液中的溶解度进行了模拟计算。结果显示:溶液中SO42-的存在对方解石、白云石溶解度的提高作用很大。如在Pco2、浓度为1200mmol／L的Na2SO4溶液中,方解石和白云石溶解度分别为纯水中溶解度的9．544和9．897倍。其作用机理是:在无同离子效应时,SO42-等所产生的盐效应和SO42-与各种阳离子形成的离子对起重要作用;而有同离子效应时,将发生白云石化或去白云石化反应,从而促使不全等溶解继续发生。与此同时,即使存在同离子效应的条件下,特别是在较高浓度条件下,盐效应的作用也是不容忽视的。 相似文献
14.
为了研究赤泥中氟向下运移过程中的影响因素,根据堆场周围的水文地质条件,设计了7组动态淋溶试验,并对试验数据进行了灰色关联度分析。结果表明,排放7天后的赤泥其表面下700 mm处的温度仍达78℃,而刚排放到堆场的冲灰水温度更高,可达87.5℃,高温赤泥和冲灰水有利于氟的迁移;赤泥的pH值为10.29～11.83,浸出液的pH值为12.00～13.20,碱性很大,致使氟易随水迁移;赤泥的其它污染组分,如总硬度、Cl-、SO42-、K+、Na+、Ca2+、Mg2+,均对氟的迁移有一定的影响,且Na+、SO42-和Ca2+为主要控制因素,即溶液中Na+、SO42-、Ca2+含量越高,赤泥中的F-离子越易淋出。 相似文献
15.
萨热阔布金矿床位于新疆阿尔泰山南缘泥盆系康布铁堡组火山碎屑岩中 ,受断裂控制 ,成矿热液蚀变以硅化、似夕卡岩化、绿泥石化为主 ,硅化蚀变矿石富Fe2 O3+FeO、SiO2 ,而似夕卡岩蚀变矿石富CaO和Al2 O3,各种矿石富集Au、Ag、Cu、Pb、Zn、Bi、Mo、W等多种元素。成矿温度为中温 (2 40℃～310℃ ) ,流体成份以Cl-/SO4 2 -高为特征 ,矿石矿物中石英Ar-Ar年龄 (32 0Ma± 6Ma)反映最终成矿构造热液叠加年龄 ,矿床属火山喷流沉积改造型金矿床 相似文献
16.
硫酸铵溶液淋滤-电感耦合等离子体质谱测定离子相稀土分量的方法优化 总被引：2，自引：2，他引：0
离子吸附型稀土中离子相稀土的准确测定对稀土矿体资源评价具有重要意义。离子相稀土以羟基或水合羟基的形式吸附在黏土矿物上,可与强电解质(Mg~(2+)、NH_4~+等)交换解吸进入溶液。前人以硫酸铵为淋滤液,实现了离子相稀土的解吸、提取,但在溶液浓度、浸取过程等方面选择各异,淋滤浸取率(60%～90%)差异大,未形成高效、统一的浸取方法,不利于离子相稀土元素的精确测定。本文通过对比实验规范了硫酸铵淋滤离子相稀土的各项淋滤参数(固液比、硫酸铵浓度、样品最佳称样量、浸泡时间),减少了淋滤过程中离子相稀土的损失,浸取率达到88%～98%,进而利用ICP-MS测定离子相稀土分量。方法检出限为0. 05～5. 11 ng/g;三类岩性离子吸附型稀土样品的精密度为:火山岩1. 80%～10. 01%,变质岩1. 06%～7. 27%,沉积岩1. 72%～7. 58%。协作实验室的分析结果验证了本方法的可靠性和准确性。本方法操作简便,分析效率高,为建立相关的行业标准乃至国家标准奠定了基础。 相似文献
17.
Granites are widespread in Guangxi Province and distributed in four tecto-magmatic zones. Geochemical characteristics of these Mesozoic granites can be outlined as: (1) petrochemically rich in silica, alkali and volatiles; (2) low oxidation ratio and relatively high Al index and K2O/Na2O ratio. As indicated by their geochemical, petrological and mineralogical features, many granites in Guangxi belong to S-type, frequently associated with mineralizations of rare-earth, tin, tungsten niobium and tantalum. 相似文献
18.
SO2-4浓度偏高是晋西柳林泉域岩溶水的主要特色之一,判断SO2-4来源对于理解岩溶水的水文地球化学过程具有重要意义。在分析区域地质、水文地质条件及岩溶水中SO2-4浓度空间分布特征的基础上,利用化学计量学法、同位素质量平衡模型和Rayleigh蒸馏模型,分析了岩溶水中SO2-4的主要来源,计算了不同来源的SO2-4所占的比例和滞流区岩溶水中SO2-4的还原比例。结果显示,石膏的溶解和黄铁矿的氧化是柳林泉域岩溶水中SO2-4的主要来源,排泄区岩溶水中石膏溶解来源的SO2-4所占比例介于73%~88%之间,平均为81%;黄铁矿氧化来源的SO2-4占比12%~27%,平均为19%。滞流区发生了硫酸盐的还原作用,约有9%~15%的SO2-4被脱硫细菌还原为H2S气体,且越靠近西部边界,还原反应所消耗的SO2-4比例越高。 相似文献
19.
层间氧化带型砂岩铀矿床地浸过程的热力学研究：以伊犁盆地512铀矿床为例 总被引：4，自引：2，他引：2
伊梨盆地512层间氧化带型砂岩铀矿床是中国第一个工业化规模开发的地浸铀矿床,作者简要地介绍了其地质特征和地浸开发工艺,并利用较新的Gibbs自由能和平衡常数数据,对该矿床地浸处理中铀的地球化学行为进行了定量研究。首先,通过标准电动势（E^o）,氧化-还原电位（Eh）的计算和分析,阐明了H2O2、硝酸盐、大气中自由氧都能提升溶液的Eh值,从而加速矿物相U^4 的氧化溶解,为了节约地浸氧化剂成本,对于U^4 /U^6 比值不太高的矿床来说,建议充分利用大气中自由氧化氧化剂,然后,通过化学平衡计算,推导出了地下水和硫酸浸出液中铀存在形式的计算公式,计算结果表明：（1）512铀矿床矿体所赋存的含矿层地下水中,铀主要以碳酸铀酰类络合物形式存在,并且以UO2（CO3)^4-3和UO2（CO3）^2-2形式为主,并随着pH从7.31升高到8.20,UO2CO3从3.80%降低到0.06%,UO2（CO3）^2-2从21.91%降低到3.12%,而UO2（CO3）^4-3则从74.28%升高到96.82%,（2）512铀矿床硫酸浸出液中,铀主要以硫酸铀酰类络合物形式存在,其中,UO2SO4占63.28%～ 63.86%,UO2(SO4)^2-2占16.55%～21.36%,UO^2 2占15.04%～19.62%,从推导出的计算公式可以看出,硫酸浸出液中铀的存在形式随溶液pH、总SO^2-4含量的变化而变化,并呈非线性关系,为了提高离子交换树脂的吸附性能,可利用文中推导出的公式进行计算,以使调节溶浸液的pH和总SO^2-4含量,从而达到浸出液中铀存在形式的最佳比例关系,最后,因热力学数据对化学反应平衡计算的影响呈指数关系,在进行热力学数据计算时,必须采用较新、较准确的数据。 相似文献
20.
Stoichiometry of smectite dissolution reaction 总被引：1，自引：0，他引：1
The dissolution stoichiometry of smectite-rich bentonites SAz-1, STx-1 and SWy-1 was studied at 50°C and pH 2 and 3 using flow-through reactors. In addition to smectite, these samples contain considerable amounts of silica phases (quartz, cristobalite and/or amorphous silica). As a result, the molar Al/Si ratios of the bulk samples are significantly lower than those of the pure smectite.Smectite dissolution was highly incongruent during the first few hundred to few thousand hours of the experiments. Release rates of Si, Mg, Ca and Na underwent a distinct transition from an initial period of rapid release to significantly lower release rate at steady state. A reversed trend was observed for release of Al, which gradually increased from very low starting release rate to higher release rate at steady state. At steady state the ratio of released Al to released Si was found to be constant and independent of the experimental conditions. We suggest that this ratio represents the Al/Si ratio of the smectite itself, and it is not influenced by the presence of accessory phases in the sample.The rapid release of calcium, sodium and magnesium from the interlayer sites is explained by ion-exchange reactions, whereas the fast release of silicon is explained by dissolution of amorphous silica. We interpret the initial slow release of Al as the result of inhibition of smectite dissolution due to coating or cementation of the smectite aggregates by amorphous silica. As the silica is dissolved, the aggregates fall apart and more smectite surfaces are exposed, resulting in an increase in the smectite dissolution rate. Thereafter, the system approaches steady state, in which the major tetrahedral and octahedral cations of smectite are released congruently. 相似文献