微波焙烧攀枝花钛渣实验研究

由于氯化法钛白工艺及电焊条产业的迅速发展,对高品位人造金红石的需求呈现快速增长的趋势。进行了攀枝花钛渣微波焙烧试验,考察了不同焙烧温度对钛渣样品的重量、二氧化钛品位、脱硫及脱碳效果的影响。结果表明,钛渣在微波焙烧条件下,低价钛逐渐氧化成高价钛,随着焙烧温度的提高,氧化效果越好,样品重量的增重先升高后降低,同时二氧化钛品位呈现先降低后升高的趋势,且硫、碳含量因为在焙烧过程中与氧气反应生成SO2、CO及CO2逸出而减少。     

酸溶性钛渣在微波场中的升温特性研究

以酸溶性钛渣为原料,探讨酸溶性钛渣在微波场中的升温特性,通过对酸溶性钛渣进行微波加热及保温处理,考察在不同微波加热温度及保温时间条件下,对酸溶性钛渣微波改性后样品二氧化钛品位及硫、碳含量的影响。结果表明:提高微波加热温度与增加保温时间,有利于物料在微波场中氧化更加彻底,低价钛与铁及铁的氧化物的氧化反应使得总量增加而二氧化钛含量相对下降,同时也实现了酸溶性钛渣在微波场中较高的脱硫率与脱碳率。     

微波焙烧高钛渣中试研究

对微波焙烧高钛渣制备人造金红石工艺进行了中试研究。采用均匀设计安排了中试实验, 验证了放大准则, 确定了放大参数, 同时考察了原料粒度、煅烧温度和通氧量等工艺条件对微波焙烧高钛渣的影响。结果表明: 微波焙烧时间是决定高钛渣氧化程度的关键参数。当高钛渣处理量为120 kg/h, 微波焙烧时间为4 h时, 最优工艺参数为原料粒度275 μm, 焙烧温度950 ℃, 通氧量0.557 m³/h, 在此条件下高钛渣的氧化率可以达到91%。     

微波焙烧高钛渣中试研究

对微波焙烧高钛渣制备人造金红石工艺进行了中试研究。采用均匀设计安排了中试试验,验证了放大准则,确定了放大后的参数,同时考察了原料粒度、煅烧温度和通氧量等工艺条件对微波焙烧高钛渣的影响。结果表明,微波焙烧时间是决定高钛渣氧化程度的关键参数。当高钛渣处理量为120kg/h,微波焙烧时间为4 h时,最优工艺参数为原料粒度275μm,焙烧温度950℃,通氧量0.557 m3/h,在此条件下高钛渣的氧化率可以达到91%。     

硫酸铵焙烧钛渣提钛的研究

通过单因素试验,研究了焙烧温度、硫酸铵与钛渣质量比、原料粒度和焙烧时间对二氧化钛提取率的影响。正交试验结果表明试验过程中各因素对二氧化钛提取率的影响由大到小的顺序为:焙烧温度焙烧时间硫酸铵与钛渣质量比。得到最佳试验条件,即在硫酸铵与钛渣质量比为5∶1、焙烧温度为470℃、钛渣粒度为44~49μm,焙烧时间为80 min时,钛渣中二氧化钛的提取率可达到80%。     

电炉钛渣制备高品位人造金红石的试验研究

以云南某地两种不同性状电炉冶炼钛渣为原料, 对氧化还原-流态化酸浸和活化焙烧-洗硅-流态化酸浸两种高钛渣制备人造金红石的工艺路线进行了试验研究, 并通过XRD、SEM分析等手段探讨了氧化还原和活化焙烧对高钛渣改性的机理。试验结果表明, 低硅含量的电炉钛渣采用氧化还原-流态化酸浸工艺可获得符合沸腾氯化钛白原料要求的人造金红石;采用活化焙烧-洗硅-酸浸工艺可得到TiO₂品位97%的细粒级人造金红石。     

硫酸铵焙烧钛渣的溶出动力学研究

对硫酸铵焙烧钛渣后的熟料进行了溶出单因素试验,研究了搅拌速率、液固比、溶出时间和溶出温度对二氧化钛溶出率的影响。得到最佳试验条件,即在搅拌速率500 r/min,液固比5∶1,溶出时间60 min,溶出温度70℃时,二氧化钛溶出率可达92%。并对硫酸铵焙烧钛渣后的熟料进行了反应动力学研究,结果表明:熟料的溶出过程受通过固体产物层的内扩散控制,溶出反应的表观活化能为20.96 k J/mol。     

攀枝花钛渣流化焙烧实验研究

针对用于生产特种焊接材料的钛系原料对其品质要求,进行了流态化焙烧攀枝花钛渣的试验研究。考察了焙烧温度为950℃,空气流量为3.3 m3/h,螺旋推料器频率为45.4 Hz条件下,流化焙烧对钛渣品质的影响。结果表明,由于焙烧过程中细颗粒直接被吹出流化床腔体而被冷却水吸收,流化焙烧后,钛渣颗粒变粗,粒度增大;XRD及Raman分析显示,攀枝花钛渣经流化氧化焙烧后,钛渣中发生晶型转变,610 cm-1处振动特征峰发生红移,低价钛转变成高价钛,金红石型Ti O2长大增多。     

攀枝花钛渣流化焙烧试验研究

针对用于生产特种焊接材料的钛系原料对其品质要求,进行了流态化焙烧攀枝花钛渣的试验研究。考察了焙烧温度为950℃,空气流量为3.3 m3/h,螺旋推料器频率为45.4 Hz条件下,流化焙烧对钛渣品质的影响。结果表明,由于焙烧过程中细颗粒直接被吹出流化床腔体而被冷却水吸收,流化焙烧后,钛渣颗粒变粗,粒度增大;XRD及Raman分析显示,攀枝花钛渣经流化氧化焙烧后,钛渣中发生晶型转变,610 cm-1处振动特征峰发生红移,低价钛转变成高价钛,金红石型Ti O2长大增多。     

氧化-还原焙烧工艺综合处理二次硫铁尾矿

采用氧化—还原焙烧工艺流程综合处理二次硫铁尾矿,考察了气体流速、焙烧温度、焙烧时间等因素对脱硫、脱砷效果以及烧渣中铁品位的影响。结果表明,采用两段氧化焙烧法分别进行脱硫、脱砷,在氧化焙烧温度为600~750℃时,处理后的氧化焙烧渣中铁的品位达到64%,然后在1100℃进行还原焙烧,可有效回收有价金属Sb、Pb、In及Zn等,且最后烧渣中铁的品位达到66%以上,可以作为优良的炼铁原料。     

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。     

Oxidation of high-titanium slags in the presence of water vapour

High-titanium slag can be oxidised by exposure to oxygen or water vapour, since the slag contains trivalent titanium and divalent iron; such oxidation is used in slag upgrading processes. The presence of water vapour may increase the rate of oxidation. To test this, samples of crushed high-titanium slag were oxidised in various mixtures of oxygen, argon, and water vapour, in a fluidised bed, at 800 °C, for up to 2 h. The presence of water vapour did increase the degree of oxidation, without changing the nature of the reaction products, which were rutile, pseudobrookite with increased iron content, and some anatase.     

含钛高炉渣钛提取中酸解率影响因素的研究

采用硫酸法对含钛高炉渣进行钛提取,对影响含钛高炉渣酸解率的因素进行了实验室研究,确定了最佳工艺参数。结果表明,影响酸解率最重要的因素为酸浓度、酸渣比和反应时间;在含钛高炉渣细度300目、酸渣比（1.8~2.2）∶1,硫酸浓度85%,反应时间40 min,熟化温度160 ℃,熟化时间4 h,浸取浓度50 g/L,浸取时间8 h,浸取温度50 ℃的条件下,酸解率在85%以上,并可得到总钛浓度50 g/L以上的合格钛液。对钛液进行水解、水解产物经煅烧后得到的TiO₂其品位超过了98%。     

偏钒酸铵掺杂高钛型高炉渣的光催化性能优化

为了实现以非提钛方法对高钛型高炉渣的综合利用,利用其含TiO2可制备光催化剂的特点,以攀钢高钛型高炉渣掺杂偏钒酸铵为原料,采用多元固相烧结法制备掺杂钒的光催化剂,在紫外光下,考察了煅烧温度、掺杂量及煅烧时间对模拟污染物亚甲基蓝溶液降解率的影响,并用XRD对催化剂进行了表征。结果表明:在煅烧温度800℃、偏钒酸铵-TiO2质量百分比45%、煅烧时间2h时,制备的掺杂光催化剂降解率达到83.5%,与未掺杂之前相比,其降解率提高了26.9%。      

TiO2/柱撑膨润土复合光催化剂制备及应用研究

以改性的新疆乌兰陵格膨润土、四氯化钛和钛酸丁酯为原料，采用柱撑多次负载法制备TiO₂／柱撑膨润土复合光催化剂。并通过改变TiO₂／柱撑膨润土的配比、负载次数、焙烧温度得到最佳制备条件。采用XRD、IR、SEM、EDS对TiO₂／柱撑膨润土复合光催化剂进行了表征。证实TiO₂呈高度分散状态，并已渗入膨润土层间结构，使层间距扩大，形成互不干扰的活性反应中心。在模拟染料废水中，对TiO₂／柱撑膨润土复合光催化剂的光催化降解性能进行了研究。同时用所制TiO₂／柱撑膨润土复合光催化剂对石化含油污水进行了光降解试验。     

Prediction of the acid generating potential of coal mining spoils

Abstract

The sulfide oxidation impact on mined land reclamation mades it necessary for mine spoils to be classified according to their acidifying potential. In this paper predictions were made of the acid generating potential of sulfide-containing spoils from the Puentes lignite mine (Galicia, NW Spain), and the limits of sulfur contents allowable for their storage in aerobic conditions, were established. Using samples of fresh spoils, analyses were made of the content and speciation of sulfur, pH was measured after oxidation of the sample with H₂O₂ (pH of oxidation=pH_ox), and titration of the oxidation extract with 0.1 N NaOH to pH = 7 was carried out (Net Acid Production=NAP). The total sulfur content (S_T) varied between <0.0l% and >3 %, with pyritic-S being the most common form (>80%). pH_ox varied between 1.6 and 6.4 and NAP between 1.2 and 85.0 Kg CaC0₃ t^?1. A high correlation was found between the NAP and the S_T(r=0.98, p<0.001). Spoils with S_T>0.15% cause high risks of mine-soil acidification., and create the need for large doses of CaCO₃ to be used on final surface of the mine dump. Use of fly ash, produced from the combustion of lignite, as an alternative to commercial lime is more effective in the control of acidity generated by spoils with high S_T.     

Calcium leaching from waste steelmaking slag: Significance of leachate chemistry and effects on slag grain mineralogy

Accelerated carbonation of alkaline wastes such as steelmaking slag offers the potential to combine waste valorisation with climate change mitigation by utilising carbon dioxide (CO₂). One method of achieving this is through an indirect carbonation process to produce a marketable precipitated calcium carbonate (PCC), using ammonium salts to selectively extract calcium from steelmaking slag. Two unaddressed design parameters for a slag based plant differing from that of a traditional PCC plant are the effect of mineralogy on extraction efficiency when using a multicomponent, heterogeneous feed such as slag and the challenges raised by the resulting leachate chemistry. This paper presents petrographic textural observations on the effect of calcium leaching via ammonium chloride on individual grains of dicalcium silicate in three different widely unutilised steelmaking slags. These observations are then interpreted in conjunction with measured changes in solution leachate chemistry. The results indicate that although silica enriched regions form at the reaction front, the reaction continues into the core of the particle due to fracture propagation caused by volume reduction as calcium is extracted. Co-leaching of sulfur alongside calcium and the formation of precipitate in the leachate highlights potential engineering challenges when the process is scaled up due to fouling of process equipment. The main mineral phases in all untreated slags were found to be calcium silicates, predominantly dicalcium silicate (Ca₂SiO₄). This was followed by a complex mixture of calcium/magnesium-wustite (CaFeMnMg)O type phases and srebrodolskite (Ca₂Fe₂O₅(Ti, V)). Results indicate that calcium silicate is the more reactive component of BOS slag, while lime bound as (CaFeMnMg)O is most reactive in HMD and SS slags. Selectivity of the ammonium chloride solvent was high at 95–97% and efficiency of calcium extraction ranged between 25% and 39%.     

TiO2 对黄金尾砂微晶泡沫玻璃非等温析晶活化能的影响

以黄金尾砂为主要原料,改变原料中晶核剂TiO2的掺量,制备微晶泡沫玻璃.运用差热分析(DSC)、X射线衍射仪(XRD)等分析手段,研究TiO2掺量对微晶泡沫玻璃析晶与发泡的影响.结果表明,随着TiO2含量的增加,析晶活化能呈现出先减小后增大的规律,当TiO2添加量为3.5％时,析晶活化能较小,为95kJ/mol;同时微晶泡沫玻璃析出的主晶相为硅灰石(CaSiO3),次晶相为钙长石(CaAl2Si2O8);当TiO2添加量为3％～4％时,制备得到的微晶泡沫玻璃具有良好的物理性能;主晶相硅灰石(CaSiO3)不随TiO2的添加改变,并且TiO2能促讲晶相牛长.