Flotation separation of andalusite from quartz using sodium petroleum sulfonate as collector

The floatability of andalusite and quartz was studied using sodium petroleum sulfonate as collector, being successfully applied in the real ore separation. The collecting performance on minerals was interpreted by means of zeta potential measurement and infrared spectroscopic analysis. The single mineral experiments showed that andalusite got good floatability in acidic pH region while quartz exhibited very poor floatability in the whole pH range. At pH 3, the presence of Fe3+ obviously activated quartz, causing the identical flotation behavior of the two minerals, and calcium lignosulphonate exhibited good selective inhibition to quartz. The real ore test results showed that andalusite concentrate with 53.46% Al2O3 and quartz concentrate with 92.74% SiO2 were obtained. The zeta potential and infrared spectroscopic analysis results indicated that chemical adsorption occurred between sodium petroleum sulfonate and andalusite.

Flotation separation of Xixia andalusite ore

The flotation behavior of Xixia andalusite was studied with different collectors.The tests were conducted with a pure andalusite sample in micro-flotation cell and then with an ore sample in a mechanical flotation cell.The surface charge was measured on pure andalusite sample and the isoelectric point（IEP） was found to be pH 5.2.Andalusite is floated with an amine collector above IEP where mineral surface is negatively charged.In contrast,an alkyl sulfonate collector（sodium dodecyl benzene sulfonate） is effective in the pH range where andalusite surface is positively charged.Furthermore,andalusite is floated with oleate in neutral and mildly alkaline pH values.55.3% Al2O3 is produced with 75.6% andalusite recovery when using the alkyl benzene sulfonate collector.Starch is found to be an effective depressant for gangue minerals in alkyl benzene sulfonate flotation.Moreover,slimes are found to have an adverse effect on the flotation of andalusite.Therefore,pretreatment by desliming and pre-float（to remove carbonaceous species） prior to andalusite flotation is necessary.

Selective flotation separation of andalusite and quartz and its mechanism

The separation of andalusite and quartz was investigated in the sodium oleate flotation system, and its mechanism was studied by solution chemical calculation, zeta-potential tests, Fourier transform infrared spectroscopic(FTIR), and X-ray photoelectron spectroscopic(XPS). The flotation tests results show that FeCl3·6H2O has a strong activation effect on andalusite and quartz and citric acid has a strong inhibitory effect on activated quartz, thus increasing the floatability difference between quartz and andalusite when the pulp p H is approximately 8. The FTIR, Zeta potential, and XPS analyses combined with the chemical calculation of flotation reagent solutions demonstrate that Fe forms hydroxide precipitates on the surface of andalusite and quartz and that oleate anions and metal ions adsorb onto the surface of the minerals. The elements Al and Fe can be chemically reacted. The anions in citric acid have different degrees of dissolution of Fe on the andalusite and quartz surfaces, thereby selectively eliminating the activation of the elemental Fe on andalusite and quartz and increasing the floatability of andalusite, leading to a better separation effect between andalusite and quartz.

Sillimanite,Kyanite and Andalusite in China and Their Applications Part Ⅰ:Their Reserve,Distribution and Characteristics

Sillimanite, kyanite and andalusite are advantageous natural refractory raw materials for aluminosilicate refractories to attain improved key properties. This paper are divided into two parts to introduce their resource and technical characteristic in the first part, and their applications in refractories in the second part to be succeeded . In this part, based on authors ' knowledge and sources , information on their reserve, distribution, composition and characteristic is provided , to bring it to light that China is rich in the reserve of them , in particular andalusite. The sillimanite group minerals are characterized by their phase transformation to form primary mullite and secondary mullite when added in high alumina system , accompanied by volume expansion , which can be taken use to improve creep resistances and thermal shock resistance of the related refractories.

Mullite Refractory Made from Andalusite and α-Al_2O_3

Mullite refractory was made from micropowder of andalusite and α-M2O3 by an ' one-step sintering process' . This refractory has a lower linear expansion coefficient, more simple process and the sintering tem-parature can be decreased 200 - 25017 . But the cool strength of the material is near to that of fused casting mullite brick. For this material, the test sum of α-Al2 O3 added is 20% , the favorable sintering temperature is 1400℃.

Effect of Andalusite Aggregate Pre-fired at Different Temperatures on Properties of Al2O3-SiC-C Castables

This work investigates the effect of the pre-firing temperature of andalusite aggregate(5-3 mm)on the conversion of andalusite,the volume stability,the thermal shock resistance and the slag resistance of Al2O3-SiC-C castables.The results show that the volume stability and the thermal shock resistance of the castables could be adjusted at different pre-firing temperatures of andalusite aggregates.There was no noticeable difference in the slag resistance between the specimens without andalusite and those with andalusite aggregate pre-fired at different temperatures.

Sillimanite, Kyanite and Andalusite in China and Their Applications Part II: Their Applications in Refractories to Improve Resistance to Creep and Thermal Shock

As a second part under the title, this paper introduces the applications of sillimanite group minerals (SGM) in refractory products for hot blast stove, blast furnace, torpedo, hot metal mixer, etc., with emphases on their uses in the low creep and thermal shock resistant bricks for tuyere and iron notch of blast furnace and checker brick and ceramic burner of hot blast stove, taking use of their phase transformation to form primary mullite and secondary mullite, accompanied by volume expansion. The developed SGM containing refractories have found wide uses in major domestic iron and steel making plants to meet the requirements of longer service life, higher service temperature and intensified operations.

Characteristics and Application of Andalusite Material and Andalusite-Based Refractory

Andalusite material and Andalusite based refractory are very popular in Europe and Japan, but its applications are restrained because of its low quality and misunderstanding in China. The paper introduced in detail the characteristics of andalusite material and andalusite based refractory based on the authors’ research work in recent years and on some references. Some information is illustrated clearly by figures and microstructure photographs. It is concluded the property of raw material and refractory is not determined by alumina content but by type and quantity of the impurities and microstructure. Mullitisation provide andalusite based refractories more excellent macro and micro properties that guarantee its popular application.

Effect of Carbon Graphite on the Crystallization of Andalusite: Application to the Synthesis of Mullite and the Improvement of Refractory Quality

Different mixtures of Moroccan silica-alumina geomaterials were used for the preparation of refractory ceramics. A formula of composition (M2) has allowed obtaining a good quality of refractory. Addition of a small quantity of carbon (1%) to the M2 formula has substantially improved the quality of the refractory. The morphological, textural and mineralogical evolution, through SEM and XRD shows that the addition of carbon, which plays a catalytic role, favors the crystallization of andalusite. Then, from 1200°C, the andalusite starts to transform to primary mullite needles. At 1400°C, the mullite becomes the major mineral phase beside cristobalite and vitreous phase.

Elaboration and Characterization of Mullite Refractory Products from Moroccan Andalusite

Enrichment of schist mined in Morocco resulted in an extract essentially made of andalusite, quartz and muscovite, which was investigated with the aim to synthesize mullite refractory materials. X-ray diffraction analysis was used to assess phase transformations upon heating at different temperatures. Mullite formation starts as early as 1200℃ and seems almost total at 1450℃. This process correlates with a weak shrinkage (3.5% at 1450℃) and the formation of an important glass phase. Green compacts obtained by unidirectional pressing the extract powder were heated under air in the temperature range 1200℃ - 1600℃. Chemical and mechanical properties of these materials were investigated and correlated with their microstructure.

Effect of Andalusite on Properties of Homogenized Bauxite Based Al2O3-SiC-C Castables

In this study,in order to evaluate the performance of homogenized bauxite,two Al_2O_3-SiC-C castables were prepared using homogenized bauxite and brown fused corundum as aggregates,respectively. 5 mass%andalusite was introduced into the two castables so as to research the effect and mechanism of andalusite in Al_2O_3-SiC-C castables. The results showed that：（1） compared with the brown fused corundum based castables,the homogenized bauxite based castables had higher cold strength after heat treatment,but lower hot modulus of rupture;（2） addition of 5 mass% andalusite could enhance the cold and hot modulus of rupture,improve the thermal shock resistance,and optimize the microstructure of specimens;（ 3） the mullitization of andalusite was not obvious in the castables fired at 1100-1400℃.

Development of Andalusite Bricks for Hot Blast Stove

Low-creep andalusite bricks are characterized by high refractoriness under load, good anti-creep property, high mechanical strength, low porosity, good thermal shock resistance, etc. In this study, low-creep andalusite brick specimens were investigated in the lab using mullite, bauxite and andalusite. Andalusite with the different particle sizes were used in the experiment and the specimen with the best property was selected us the production standard. In addition, the industrial produced low-creep andalusite bricks were compared with other low-creep bricks. The results show that the developed low-creep andalusite bricks is an excellent material for hot blast stove.

Kyanite Sillimanite and Andalusite

1 Scope This standard specifies classification, symbol, brand,technical requirements, test methods, inspection rules,packing, marking and quality certificate of concentratedkyanite, sillimanite and andalusite. This standard is applied to the beneficiated kyanite,sillimanite and andalusite used for high quality refracto-ries, technical ceramics and Si-Al alloy.

Effect of Andalusite Addition on Properties of Chrome-corundum Bricks

In order to improve the thermal shock resistance of chrome-corundum bricks,different amounts of andalusite were added to the formulation of chrome-corundum bricks to replace the equivalent white fused corundum with the same particle size.After mixing,shaping,drying and firing,the density,the cold strength,the cold wear resistance,the hot modulus of rupture and the thermal shock resistance were tested.XRD,SEM and elemental surface scanning were used to characterize the specimens.The results show that:(1)the volume expansion of andalusite mullitization reduces the apparent porosity of chrome-corundum bricks;(2)the density and the hardness of mullite are lower than those of corundum so the decrease of the corundum content in brick leads to the decrease of the bulk density,the strength and the cold wear resistance;(3)the cross-distributed columnar mullite in the matrix can effectively improve the hot modulus of rupture and the thermal shock resistance of the specimens;(4)considering comprehensively,the andalusite addition shall not exceed 18%.

Development of Anti-Creep Andalusite-Based Bricks for Blast Furnace Stove

Secondary nudlitization and mineral phase compositions of reacting andalusite of different gain sizes with fine alumina powders are studied. By adopting reasonable process technology to control nudlitization behavior during firing, good anti-creep andalusite bricks have been developed.

Effect of Some Additives on the Microstructure and Properties ofAndalusite-cordierite Refractory

The effect of some additives on the microstructure and properties of andalusite-cordierite refractory is concerned with. A study has been made on Al2O3, Cr2O3 and SiC powders, which are selected as additives and added respectively to the standard formulation in varying amounts as extra content (2%, 4%, or 6%). As the results indicate, Al2O3 (best at 4%) and SiC (best at 2%) can improve the microstructure and the properties of the material.But Cr2O3 shows the effect to the contrary.

红柱石原料高温结构演变及抗钾蒸气侵蚀行为研究

红柱石是铝硅系耐火材料重要的原料之一,因完全莫来石化后具有莫来石-高硅氧玻璃相相间的结构而表现出优异的抗碱侵蚀性能。然而,其莫来石化程度与抗碱侵蚀性能之间的关系尚未厘清。为此,本工作以粒度为3~5 mm的红柱石为研究对象,在1450~1600℃下热处理红柱石3 h,研究了红柱石的莫来石化过程与结构演变,并采用碱蒸气法研究了抗碱侵蚀行为。结果表明,随着热处理温度的提高,红柱石表面及裂纹附近先转变形成莫来石-高硅氧玻璃相结构,随后莫来石化转变不断向内部发展,直至完全莫来石化。红柱石莫来石化程度不同决定了其不同的抗碱侵蚀行为。1450℃热处理后的红柱石表面及大裂纹附近形成的莫来石-高硅氧玻璃相复合层较薄,侵蚀以红柱石与钾蒸气直接反应为主,抗碱侵蚀性能较差;1500℃及以上温度热处理的红柱石表面及大裂纹附近形成了一定厚度的莫来石-高硅氧玻璃相复合层,钾蒸气首先与高硅氧玻璃相反应形成含钾硅酸盐液相,随后该液相对莫来石相产生侵蚀溶解,阻止了碱蒸气对莫来石的直接反应侵蚀,从而使红柱石表现出优良的抗碱侵蚀性能。

骨料特性对刚玉-莫来石浇注料性能的影响

刚玉-莫来石浇注料主要用于各类窑炉内衬材料的制备,为进一步提高内衬材料的使用性能,采用杂质含量不同的预合成莫来石和红柱石,研究了骨料种类和杂质含量对刚玉-莫来石浇注料显微结构与力学性能的影响。结果表明,当热处理温度为1100℃和1550℃时,莫来石骨料的杂质元素扩散进入基质中,降低了基质中液相的生成温度,促进了浇注料的烧结,因此添加莫来石骨料的浇注料比添加红柱石骨料的浇注料力学性能更加优异;杂质含量高的MS60骨料在高温下形成的液相较多,能够有效促进浇注料的烧结,提升浇注料的常温力学性能,其在1550℃时的抗折强度和抗压强度分别为10.7 MPa和115.2 MPa。但高温抗折强度会因液相较多而降低,其值为0.7 MPa;杂质含量高的红柱石骨料D59的莫来石化程度大,产生的富硅玻璃相黏度低,可以促进浇注料的烧结和二次莫来石生成,从而改善浇注料的力学性能,D59浇注料的高温抗折强度为0.7 MPa。

周口店地区接触变质岩的演化:来自碳质拉曼光谱温度计的证据

燕山板内构造带是华北克拉通中部遭受长期造山演化作用的活动区,详细的岩浆活动和变质作用研究对于恢复其造山热演化过程具有重要意义。构造带内周口店地区的房山岩体是中生代燕山运动晚期的产物,但关于房山岩体周缘受到接触热变质作用的古老地体变质演化历史却缺乏详细的研究。本研究在房山岩体红柱石-黑云母接触变质带内采集了岩石样品,通过岩相学的详细观察和碳质物拉曼光谱温度计的计算,得到了以下认识:岩石中红柱石斑晶核部的碳质包体记录下了早期区域变质过程的变质温度(约550℃),红柱石斑晶及边部中的碳质包体共同记录了峰期变质温度条件(约598℃),岩石基质中碳质包体可能记录了岩石接触热变质的峰后期变质温度(598~574℃)。研究结果表明,接触热变质带的岩石受到房山侵入岩释放的热量而迅速加热,在达到峰期变质温度后又随岩体的冷却而降温,导致了近等压的p-T-t轨迹。

红柱石、蓝晶石和夕线石的相变与变形

红柱石、蓝晶石和夕线石是铝硅酸盐(Al_(2)SiO_(5))的3种同质多像体,其晶体结构、物理性质和温度、压力稳定范围各不相同。研究它们的矿物共生组合、相变和变形,可以解析矿物结晶顺序、变质与变形历史。本文对已有的天然样品和实验岩石学研究成果进行综合分析,发现Al_(2)SiO_(5)的多相转变和相平衡关系受化学组成、流体、温度和压力等环境条件的影响;Al_(2)SiO_(5)的双相或三相共生组合通常是亚稳态的;矿物结晶顺序记录着区域的温度压力轨迹和构造演化历史。变质岩石中,Al_(2)SiO_(5)矿物可以形成不同强度的结晶学优选方位,其中c[001]轴近似平行线理方向,红柱石、蓝晶石和夕线石的主滑移系分别为(110)[001]、(100)[001]和(010)[001]或(100)[001]。目前,红柱石-夕线石转变线位置和三相点的温压条件还存在争议,三相矿物的共生组合是变质过程的亚稳态共存状态,不能代表三相点的温压条件。