微波制备人造金红石及其相转变的研究

天然金红石是生产钛白粉的重要原料之一。目前,可利用的高品位天然金红石资源日渐枯竭,探索一种在较低能耗以及较小环境污染下生产人造金红石的方法已日趋迫切。微波加热技术现已广泛的应用于试验和工业生产中,与传统加热相比,有着选择性加热,加热速度快等优点。本文以云南高钛渣为原料提出一种微波加热制备高品质人造金红石产品的新工艺,并利用X射线衍射,扫描电子显微镜,能谱分析等方法对产物进行表征与分析。XRD分析结果表明,高钛渣的主要成分是铁钛氧化物的固熔体,其中的二氧化钛大多是以锐钛矿形式存在,也含少量的金红石相。经过微波焙烧后,锐钛矿的峰已经消失,金红石的峰增强。SEM-EDAX分析结果表明高钛渣表观型貌图中高钛渣颗粒表面比较光滑、平整,但经微波焙烧后物料生成了一些形状不是很规则的短棒状体,这些棒状体即为金红石相。     

湖北枣阳细粒原生金红石矿浮选分离研究

湖北枣阳金红石矿含Ti O23.06%,主要有用矿物为金红石,脉石矿物为角闪石、钙铁榴石,矿石嵌布关系复杂,为细粒难选矿石。针对该难选矿石,进行了浮选试验研究,捕收剂采用C5⁹羟肟酸+苄基砷酸(BAA)组合用药,浮选闭路试验表明采用二者组合用药,可获得金红石粗精矿Ti O2品位43.30%、回收率67.98%,基本实现金红石的有效分离,试验指标良好。     

Formation of TIB2 from rutile by room temperature ball milling

A mixture of rutile, boron oxide and magnesium has been ball milled together with the intention of inducing a reaction to form titanium diboride. The resultant powders were examined by differential thermal analysis, isothermal annealing and X-ray diffraction to determine the effect of milling on the formation of TiB₂. Complete reaction was found to occur in the mill between 10 and 15 h forming TiB₂ and MgO with no residual Mg. The unwanted phase, MgO, was readily removed by leaching in acid leaving a fine powder composed of aggregates of TiB₂. The feasibility of using this relatively simple, low technology route to value add for minerals is also discussed.     

Technical note bench scale flotation of a brazilian monazite ore

Preliminary studies of the floatability characteristics of monazite, zircon and rutile, performed in a modified Hallimond tube, initiated a bench scale investigation of the flotation of a Brazilian monazite ore from Sao Goncalo do Sapucai, MG. The testwork was conducted with the utilisation of a commercial hydroxamate and sodium oleate as collectors and sodium metasilicate as depressant. In all tests, the best collector/depressant ratio defined during the microflotation experiments was confirmed at bench scale. The results indicated that with both collectors it is possible to produce a high purity cleaner monazite concentrate (> 60% RE₂O₃). The concentrations of collector and depressant must be well defined to prevent a significant increase in the flotation of gamgue minerals such as ilmenite, zircon and rutile, causing contamination of the monazite concentrate.     

河南淅川石墨矿工艺矿物学研究

采用X射线衍射分析、X射线荧光分析、偏光显微镜分析等测试手段对淅川县五个不同矿点的石墨矿进行系统的工艺矿物学研究。结果表明该地石墨矿石固定碳含量11%左右,杂质成分以SiO2、Al2O3为主。目的矿物是石墨,含量10%左右,脉石矿物以石英、白云母为主,含量分别约为40%、25%,石墨主要与石英、白云母相间分布。五个矿点可归为两类(1#、2#为第Ⅰ类,3#、4#和5#样为Ⅱ类),这两类石墨片的粒度不同,要使石墨单体解离达到90%以上,磨矿细度分别需达到-0.0026mm、-0.013mm。综合分析,该两类石墨矿均属于难选石墨矿,而第Ⅰ类(1#和2#样)石墨矿比第Ⅱ类(3#、4#和5#样)更加难选。     

Research on the recycling of valuable metals in spent Al2O3-based catalyst

A new technology was developed to recover multiple valuable elements in the spent Al₂O₃-based catalyst by X-ray phase analysis and exploratory experiments. The experiment results showed: In the condition of roasting temperature of 750 °C and roasting time of 30 min, mol ratio of Na₂O: Al₂O₃ 1.2, the leaching rate of alumina, vanadium and molybdenum in the spent catalyst is 97.2%, 95.8% and 98.9%, respectively. Vanadium and molybdenum in sodium aluminate solution can be recovered by barium hydroxide and barium aluminate, the precipitation rate of vanadium and molybdenum is 94.8% and 92.6%. Al(OH)₃ is prepared from sodium aluminate solution with carbonation decomposition process, and the purity of Al₂O₃ is 99.9% after calcinations, the recovery of alumina can reach 90.6% in the whole process. The Ni–Co concentrate was leached by sulfuric acid, a nickel recovery of 98.2% and over 98.5% cobalt recovery was obtained respectively under the experimental condition of 30% (w/w) H₂SO₄, 80 °C, reaction time 4 h, liquid:solid ratio (8:1) by weight, stirring rate of 800 rpm.     

高钛渣氧化焙烧行为研究

针对钛工业对人造金红石品质的要求,进行高钛渣常规氧化焙烧试验,考察不同焙烧温度下高钛渣样品重量变化、二氧化钛品位、脱硫和脱碳效果。结果表明,高钛渣在常规焙烧条件下主要发生低价金属氧化物的氧化反应,随着焙烧温度的提高,氧化反应越容易进行,因此样品重量增重越明显,同时二氧化钛品位由于样品总重量的增加而明显下降,而杂质中的硫和碳在高温下与氧结合生成SO2、CO和CO2逸出。     

用浮选捕收剂处理电解铜废水的试验研究

电解铜废水主要含有Cu₂ 、Pb₂ 、Zn₂ 、Cd₂ 、Ni₂ 等离子,对人类健康和环境危害很大。因此,对电解铜废水进行处理方法的研究十分必要。本文研究用浮选捕集剂乙基黄药处理电解铜废水。研究结果表明：在调节该废水pH = 6.6的条件下,乙基黄药(10%)投加量20.0 mL/L,快搅时间1.5 min,慢搅时间10 min时Cu₂ 、Pb₂ 、Zn₂ 、Cd₂ 、Ni₂ 的去除率均可达到95%,处理后废水中重金属残留浓度均达到了国家污水综合排放标准(GB8978-2002)的允许排放浓度或一级标准。对重金属螯合物进行的稳定性研究指出,在pH = 9时,乙基黄药的重金属螯合物中Cu₂ 、Pb₂ 、Zn₂ 的泄漏量均为0 mg/g,Cd₂ 的泄漏量为0.8?10_-3 mg/g,Ni₂ 的泄漏量为14.2?10_-3 mg/g,处理后的污泥稳定性好,对环境无二次污染。浮选捕收剂乙基黄药具有pH应用范围广、操作简单、处理成本低、效果稳定等优点,在重金属废水治理中具有良好的应用前景。     

LiMn0.6Fe0.4PO4/C纳米片正极材料的水热合成及其电化学性能

采用乙二醇辅助的水热法合成了锂离子电池LiMn0.6Fe0.4PO4/C纳米片正极材料,并采用X射线衍射(XRD)及其Rietveld精修和扫描电子显微镜(SEM)研究了材料的结构与形貌;采用循环伏安(CV)和充放电测试研究了材料的电化学性能。XRD及其Rietveld精修表明,LiMn0.6Fe0.4PO4/C纳米片具有与LiMnPO4类似的结构,无杂质峰。SEM表明,LiMn0.6Fe0.4PO4/C的形貌为片层状结构。CV表明,LiMn0.6Fe0.4PO4/C存在Mn2 /Mn3 和Fe2 /Fe3 两步转化过程。充放电测试结果表明,LiMn0.6Fe0.4PO4/C纳米片具有较好的倍率容量和循环稳定性。5C倍率放电时,100次循环的容量仍高达115.8 mAh/g左右,容量保有率为95.8%。     

The development of a composite collector for the flotation of rutile

A study was carried out to find a replacement for benzyl arsenic acid (BAA) that was used in the rutile flotation circuit of a hard rock rutile mine in China. Several types of oxide collectors were tested, including sodium oleate, sodium laurate, sodium dodecyl sulphate, amino acids, diphosphonic acid and styryl phosphonic acid. It was found that styryl phosphonic acid (SPA) was the most effective, and that an aliphatic alcohol (e.g., octanol) was required to maintain the effectiveness of SPA.However, octanol was insoluble in water. The composite collector that was mixed with SPA and octanol had to be well emulsified before addition to flotation pulp. Poorly emulsified composite collectors destroyed flotation froths. Several surfactants were tested as emulsifiers and one was found to have the least adverse effects on the selectivity of the composite collector. By using the composite collector that contained SPA, octanol and the emulsifier, a rutile rougher concentrate assaying 71.3% TiO₂ was floated at 81.6% recovery from a feed containing 8.78% Ti0₂ in a single stage rougher flotation.     

Effect of refractory agent on ash fusibility temperatures of briquette

To solve the problem of the low ash fusion point of briquette, this paper reported that the ash fusibility temperatures can be elevated by changing ash ingredients through blending refractory agents in briquette ash, which will create favorable conditions for moving bed continuous gasification of briquette with oxygen-rich air. The effects of Al₂O₃, SiO₂, kaolin, dry powder and bentonite on ash fusibility temperatures were studied, based upon the relationship between briquette ash components and ash fusibility. The results show that the increasing of ash fusibility temperatures by adding the same amount (11%, w) of refractory agents follows the sequence of SiO₂, bentonite, dry powder, kaolin, Al₂O₃, with the softening temperatures being elevated by 37.2, 57.6, 60.4, 82.6 and 104.4 °. With the same ratio of SiO₂/Al₂O₃ in briquette, adding the Al₂O₃ component is more effective than SiO₂ for raising ash fusibility temperatures. In this paper, inexpensive kaolin and bentonite rich in Al₂O₃ are found to be better refractory agents, and the suitable adding quantities are 9% and 11%, respectively.     

滨海型钛铁砂矿生产高端金红石的分析研究

利用X射线衍射和化学分析方法对滨海型钛铁砂矿进行了检测分析。结果表明: 滨海型钛铁砂矿主要由18.1%的钛铁矿和77.4%的铁金红石组成, 原钛铁矿中的Fe(Ⅱ)大部分氧化成Fe(Ⅲ)。利用还原-流态化浸出法, 从滨海型钛铁砂矿制备了人造金红石, 利用X射线衍射、光学显微镜、化学分析和粒度筛分对产物人造金红石进行了检测分析。结果表明: 该人造金红石是金红石型TiO₂, 其中TiO₂含量(质量分数)为96.12%, CaO+MgO含量为0.21%, 多孔空心结构, +150 μm粒级占96.5%, 属于高端人造金红石产品, 是氯化钛白和海绵钛生产的理想原料。     

不同磨矿分级方式对长石矿分选效果的影响

本溪长石矿含有褐铁矿、伊利石、金红石等杂质矿物,为提高该长石品级,开展了不同磨矿分级方式的选矿研究。通过考察实验室磨矿、连续磨矿-螺旋闭路分级、连续磨矿-高频细筛闭路分级3种磨矿方式,磨矿细度为-0.074mm 52%时,将3种磨矿试样以强磁选-浮选流程杂质并分离石英。结果表明:连续磨矿-高频细筛方式的粒度组成较好,其筛下试样能取得更好的分选效果,最终得到产率为50.64%,Na2O含量为11.04%,收率为70.25%的长石精矿,为该长石矿工程化生产提供了依据。     

Stability of Coatings on Sulfide Minerals in Acidic and Low-Temperature Environments

The effectiveness of silicate- and phosphate-based surface coating agents (Na₂SiO₃, CaSiO₃, and KH₂PO₄) in inhibiting the oxidation of sulfide minerals in acidic and low temperature conditions was studied. Rock samples were coated using two oxidation methods: H₂O₂ was mixed with the coating agents in one, whereas in the second, H₂O₂ was applied to the rock surface prior to the coating agent. The second approach was ineffective, but with Method 1, the pH (5) was above the pH (3.6) of the uncoated control sample. Oxidation, calculated after 14 weeks, had been suppressed by up to 96 and 65%, as indicated by the release of Fe²⁺ and SO₄ ^2?, respectively. All three coating agents (at concentrations of 0.1 and 0.3 M) suppressed the release of Fe²⁺ (<3 mg L^??1). Na₂SiO₃ inhibited Fe²⁺ and SO₄ ^2? release by 94 and 65%, respectively. Surface protection (or oxidation inhibition) efficiencies of KH₂PO₄ (in terms of Fe²⁺ release) were 67, 94, and 96% with 0.05, 0.1, and 0.3 M, respectively. The Na₂SiO₃ and CaSiO₃ coatings, irrespective of their concentrations, reduced iron oxidation by 94 and 84%, respectively. Fourier transform infrared spectroscopy analysis of the Na₂SiO₃ treated samples showed the presence of iron silicate coatings. Based on this work, coating of rock samples with silicate or phosphate can reduce the oxidation rate of sulfide minerals in acidic and low temperature conditions.     

Cobalt recovery from mixed Co–Mn hydroxide precipitates by ammonia–ammonium carbonate leaching

The research work presented in this paper focused on the recovery of cobalt from mixed Co–Mn hydroxide precipitates (obtained from sulphate leach liquors of nickel oxide ore), using ammonia–ammonium carbonate leaching. The characterization of the initial mixed hydroxide precipitates, as well as the corresponding leached residue was carried out by X-ray Diffraction, TG–DTA and Scanning Electron Microscopy.Cobalt and manganese precipitation was based on the statistical design and analysis of experiments, in order to determine the main effects and interactions of the precipitation factors, which were the equilibrium pH and the temperature. Co and Mn were precipitated as hydroxides at pH = 10.5 and T = 25 °C, using 5 M NaOH as a neutralizing agent, by 99.9% and 99.5%, respectively. The main mineralogical phases were, Mn₃O₄ (Hausmannite), γ-Mn₃O₄ and CoMn₂O₄, while Co(OH)₂ and Mn(OH)₂ (Pyrochroite) were also present as minor constituents.Cobalt and manganese separation was based on selective cobalt recovery by ammonia–ammonium carbonate leaching of the produced mixed hydroxide precipitate. The factors studied were the ammonia–ammonium carbonate concentration and the solid to liquid ratio. The cobalt recovery efficiency reached 93%. Mn₃O₄ (Hausmannite) was the main mineralogical phase of the leached residue, while MnCO₃ (Rhodochrosite) and Mn₂O₃ were also present. Small quantities of cobalt were also observed in the residue as CoMn₂O₄.     

Understanding the influence of acidic components (Si,Al, and Ti) on ash flow temperature of South African coal sources

Ash flow temperature is one property that specifically gives more information on the suitability of a coal source for combustion or gasification purposes. Therefore the chemistry and mineral interaction have to be understood in order to determine the suitability for fixed bed gasification purposes with regards to ash flow properties. Various authors ([Seggiani, M., 1999. Empirical correlations of the ash flow temperatures and temperature of critical viscosity for coal and biomass ashes. Fuel 78, 1121; Alpern, B., Nahuys, J., Martinez, L., 1984. Mineral matter in ashy and non-washable coals—its influence on chemical properties. Commun. Serv. Geol. Portugal 70 (2), 299]) have expressed the fusibility of coal ash as a function of the content of the principal oxides frequently found in coal ash, i.e. SiO₂, Al₂O₃, TiO₂, Fe₂O₃, CaO, MgO, Na₂O and K₂O. However, coal ash fusibility characteristics are difficult to determine precisely, partly because coal ash contains many components with different chemical behaviours, and may very from coal source to coal source.The purpose of this study is primarily to understand the effect and chemistry of the acidic components (Si, Al and Ti) of South African coal sources, as well as the manipulation or addition of these components to the coal sources, with the view to understand their effect on the ash flow properties.A representative coal blend as it is currently used for gasification purposes, as well as coal mixtures with the addition of pure SiO₂, Al₂O₃ and TiO₂, respectively, were prepared. The variation of the acidic components SiO₂, Al₂O₃ and TiO₂ varied from 1 mass% to 50 mass% to the coal blend. The particle size of the samples were representatively prepared to <1 mm and analyzed for ash flow temperature and ash composition as dependant variables according to ASTM D1857-87 and ASTM D2795-95, respectively. The raw data was then statistically evaluated by means of regression models.Results of the statistical evaluation of ash flow temperature and the ash elemental composition indicated that based on the 95% confidence interval Al₂O₃, Fe₂O₃, CaO, MgO, P₂O₅, as well as the SiO₂–Al₂O₃ ratio have a statistical significant effect on ash flow temperature. Regression trends of the coal and Al₂O₃, SiO₂ and TiO₂ mixtures indicated that Al₂O₃ has the biggest effect on the ash flow temperature. A shift towards increasing the Al₂O₃ concentration has a significant increasing effect on the ash flow temperature in the three-component system Al₂O₃–SiO₂–TiO₂ phase diagram. The ash flow temperature is the highest at the point where the Al₂O₃ concentration is maximized. The shifts in frequency of the absorption band associated with the 6s–6p electron transaction which relates to the basicity of a glass or slag also relates to the different effect of the individual acidic components on ash flow temperature. The shift can be considered as a measure of the electron donor power and is usually expressed in terms of the optical (Λ) basicity. The ion–oxygen attraction and the stronger (more positive) value obtained for Al₂O₃ in comparison with TiO₂ and SiO₂ could be seen; and possibly explain why Al₂O₃ has a bigger influence and effect on increasing the ash flow temperature.It can be concluded from this experimental work with the emphasis on flow properties, that the acidic components Al₂O₃, SiO₂ and TiO₂ all have an increasing effect on ash flow temperature when added to the coal blends currently used for gasification. In addition to this general conclusion, it has also been confirmed that Al₂O₃ addition to the coal blend has the most significant effect towards increasing the ash flow temperature when compared to SiO₂ and TiO₂.     

Mechanochemical processing of chrysocolla with sodium sulphide

Autogenous solid state processing of chrysocolla with sodium sulphide has been carried out at different CuSiO₃–Na₂S-ratios, particle sizes and temperatures. Water soluble sodium silicate (Na₂SiO₃) and covellite (CuS) were determined by means of chemical analysis and X-ray examination as reaction products. More than 84% of chrysocolla and 50% of associated malachite were converted to covellite at 80 °C, atmospheric pressure, 10 min contact time, stochiometric CuSiO₃–Na₂S-ratio and particle sizes of <100 μm. The mechanochemical treatment using a vibrating mill increases the conversion rate of chrysocolla and malachite up to 90% and 70%, respectively. After washing of the products, the sodium silicate solution was converted into sodium sulphate (Na₂SO₄) by adding sulphuric acid, with precipitation of silica as by-product. In addition, the carbothermic reduction of crystallised sodium sulphate led to sodium sulphide necessary for solid state processing.     

滤纸模板法制备Ag-SnO_2电接触材料

首先以纳米SnO_2粉体和Ag NO3为原料,滤纸为模板,通过浸渍、煅烧制备了Ag-SnO_2复合粉体,然后利用Ag-SnO_2粉体为原料,采用压制、烧结工艺制备了Ag-SnO_2电接触合金。进一步通过XRD和SEM等分析手段对所制备的复合粉体和合金样品进行表征,并借助TG-DSC对滤纸前躯体的分解过程进行分析,同时研究了不同纳米SnO_2含量对Ag-SnO_2电接触合金组织和性能的影响。结果表明,所制备的Ag-SnO_2复合粉体由四方相金红石型结构的SnO_2和立方相的银组成,模板去除干净,无杂质引入。由于滤纸模板的引入使得SnO_2颗粒弥散分布于银基体中。随着SnO_2含量的增加,Ag-SnO_2电接触合金的硬度有上升趋势,但高氧化物含量也导致模板的分散效果变差,使得合金的电导率和致密度逐渐降低。     

云南文山某细粒钛铁矿选矿试验研究

云南文山某钛铁矿原矿含TiO25.96%,以钛铁矿为主,还含有少量的金红石。原矿经磨矿分级控制入选粒度为-0.5 mm,采用水力分级后重选,水力分级粒度为0.038 mm,重选工艺流程为螺旋溜槽粗选、摇床精选,得到品位46.67%,回收率59.01%的钛精矿。该工艺流程简单,投资小、选矿成本低。     

贵州某难选硅质胶磷矿正-反浮选试验研究

对贵州某难选硅质胶磷矿进行正-反浮选试验研究,以GC-4为捕收剂,经过一粗二精一扫正浮选脱硅和一段反浮选脱镁工艺流程,最终获得磷精矿P₂O₅品位34.65%、回收率92.39%,MER值7.18%的良好指标,该磷精矿可直接用于湿法磷酸的生产,同时获得了P₂O₅品位19.80%、SiO₂含量29.23%、MgO含量1.23%,倍半氧化物含量12.52%的中精矿,该部分可直接用于生产中低端磷复肥。试验结果表明,GC-4是一种多功能捕收剂,泡沫稳定性可控,流动性好,最终指标较好,可以作为单一捕收剂参与正-反浮选,同时避免了因pH不同造成多种捕收剂相互影响的局面,也有利于正-反浮选回水的混合再利用;WFS是磷化工酸性废水,在磷矿反浮选中取得较好效果,可以代替H₂SO₄作为反浮选的抑制剂,同时节约生产成本,提高社会效益。GC-4和WFS在本试验的成功应用为该类复杂难处理胶磷矿规模化利用提供技术参考。