砷钙渣碳热还原分解热力学分析及试验研究

运用热力学计算软件HSC Chemistry 6.0对砷钙渣碳热还原分解反应进行热力学分析,发现还原气氛下可有效降低CaSO_4、Ca_3(AsO_4)_2的分解温度。根据分析结果在管式炉中进行砷钙渣碳热还原分解试验,并考查反应温度、还原剂量、反应时间对砷钙渣分解的影响。试验结果表明,在温度1 200℃、还原剂量25%、反应时间3h最优条件下,砷挥发率93.75%,脱砷渣中CaO含量78.87%。     

铁闪锌矿碳热还原机理研究

研究了人工合成铁门锌矿（Zn，Fe）S的高温反应性能，明确了其在只有碳质还原剂存在时具有良好的热稳定性，但极易被氧化钙分解；在碳质还原刘存在的强还原气氛下，铁门锌矿与氧化钙之间的反应更易进行，查清了其离解的条件与机理。     

电解锰渣的理化特征及其开发应用的研究

化学成分、DTA、XRD图谱分析和对不同温度下煅烧的电解锰渣的强度测试表明：电解锰渣属工业副产品化学石膏,低温下无水化活性和胶凝性,经一定温度煅烧后,具有较好的脱水石膏活性和火山灰活性.     

钛石膏在烧结砖中的应用研究

钛石膏为硫酸法钛白生产过程中的副产品,每生产1 t钛白会产出4~5 t钛石膏。将钛石膏进行预处理后作为黏结剂加入以煤矸石为主要原料的烧结砖中,有效解决了钛石膏堆存和环境污染问题。通过条件试验和正交试验,研究了煅烧温度、黏土添加量、钛石膏添加量和高温保温时间对强度的影响。条件试验表明:烧结砖强度随黏土配入量、煅烧温度和高温保持时间增加而增加,随钛石膏加入量增加而降低。正交试验表明:在黏土添加量相对稳定(20%左右)的条件下,其余3因素对烧结砖强度影响大小依次为:钛石膏添加量高温保温时间煅烧温度。最佳参数分别为:钛石膏的添加量14%,高温保温时间8 h,煅烧温度1 000℃。     

污酸石膏渣热分解行为及砷固化特性分析

分析了污酸石膏渣的成分、砷物相等,采用热重差热分析法(TG-DSC)探讨了污酸石膏渣的热分解行为,开展了不同温度下砷的挥发特性分析.结果 表明,污酸石膏渣中砷物相主要以砷酸盐和砷氧化物为主,分别占63.02％和35.59％;游离水、结晶水的脱除集中在180℃以下,硫酸钙的分解在1 150℃以上;在900℃时煅烧,砷挥发...     

TiCl_4精制尾渣的回收利用研究

对海绵钛厂Ti Cl4精制工艺尾渣的回收利用进行了研究。在对尾渣元素组成和物性分析的基础上,提出了高温煅烧尾渣制备钒渣的工艺。对煅烧温度、物料粒度以及煅烧时间等进行条件试验。结果表明,在煅烧温度≥600℃,煅烧时间大于2 h条件下,可将尾渣制备成TV在8%~12%、Cl含量小于0.3%的钒渣,V收率达到95%,Cl逸出率达到99%。     

EDTA滴定法测定钒渣中氧化钙

通过试验,确定了盐酸、硝酸、高氯酸分解钒渣样品,或碳酸钠-硼酸混合熔剂高温熔融样品后酸浸取的样品分解方式。在硝酸介质中,向试液中加入0.3～0.5 g氯酸钾,使锰形成二氧化锰沉淀,过滤沉淀后,在酸性条件下用无水乙醇将滤液中的钒还原为钒,用氨水调节pH 6~7,绝大部分的钒和铁、钛、铝、稀土等可生成沉淀,沉淀物经过滤被分离。调节滤液pH 7后,加入少量铜试剂分离残余的钒和金属离子,分取试液采用EDTA滴定法测定钒渣样品中的氧化钙含量。随机抽取一个钒渣样品,采用混合熔剂熔融处理样品后进行EDTA滴定法分析,11次测定结果的相对标准偏差为3.1%。对钒渣实际样品中的氧化钙量进行测定,结果与行业标准(YB/T 547.3-1995火焰原子吸收光谱法和高锰酸钾容量法测定氧化钙含量)的测定值一致;对钒渣标准样品进行分析,测定值与认定值一致。     

铜渣熔融还原回收铁试验研究

以铜浮选尾渣为原料,采用直接熔融还原—磁选的方法回收铁,探讨了在焙烧温度为1 350℃时,碳粉、氧化钙用量及焙烧恒温时间对还原渣磁选过程铁回收率与铁精矿品位的影响。结果表明,在碳粉和氧化钙添加量分别为铜渣质量的32%和10%、恒温100min的条件下对浮选尾渣进行熔融还原,焙烧后的产物破碎磨细至-0.074mm占85%,再进行弱磁选,可获得铁品位为67.47%的还原铁精矿,铁回收率为92.32%。     

炼钢温度下小颗粒石灰石热分解反应机理

转炉喷吹石灰石粉造渣脱磷有利于提高其反应效率，在快速造渣同时还可资源化利用CO₂。为此基于热重-差热分析仪和高温管式炉，对小颗粒石灰石在炼钢温度下的分解行为进行研究。研究结果表明，升温速率越小，小颗粒石灰石分解反应开始温度和完成温度越低，且升温速率越大分解反应持续时间越短；粒径2.5 mm以下的石灰石颗粒均可以在1 000℃以下快速完成分解反应，且粒径越小分解越快，反应完成温度越低，可见转炉采用喷粉方式可减少造渣时间，提高冶炼效率；与N₂、空气、O₂气氛相比，在纯CO₂气氛下，石灰石热分解反应完成温度提高，但分解所需时间反而缩短1/3,随着CO₂分压增加，分解完成温度提高但分解速度加快；随着煅烧温度提高，不同颗粒度石灰石分解完全所需时间均有不同程度的缩短，且粒径越大缩短程度越明显；在同一煅烧温度下，随着石灰石颗粒度由小到大，石灰石完全转化所需时间呈现由长到短再到长的趋势。仅从小颗粒石灰石煅烧效率上讲，转炉喷吹石灰石粉粒径选取0.13～1.5 mm为宜。     

液态高铅渣直接还原试验研究

以豫光氧气底吹炉所产高铅渣为原料,配入碳质还原剂,在高温熔融态下还原高铅渣中的铅,并对还原过程进行了系统研究。结果表明,最佳还原条件为:还原温度1 150℃、还原时间1 h、还原剂率3.5%。在上述条件下,高铅渣还原进行得较彻底,渣含铅可降到3%左右。     

高碳铬铁中硅的快速分析方法研究

采用氟硅酸钾滴定法测定高碳铬铁中的硅。试样用KOH和KNO3混合熔剂在镍坩埚中熔融,选取了最好的熔融条件,熔融温度600℃,熔融时间10 min。该条件下减少了对镍坩埚的损害,易于浸取。采用自制的抽滤装置,过滤速度快,滤纸无穿漏,吸附的残余酸量很少,易于洗涤和中和。样品平行测定的相对标准偏差在0.52%～3.67%,回收率实验结果为98.72%～101.30%。此方法快速简便,经大量生产实践检验,结果可靠,能够满足日常分析检测需要。     

鱼雷罐用铝碳化硅碳砖中碳化硅的氟硅酸钾滴定法研究

探讨了测定鱼雷罐用铝碳化硅碳砖中碳化硅的氟硅酸钾滴定方法。用KOH和KNO₃混合熔剂在镍坩埚中熔融鱼雷罐用铝碳化硅碳砖,选取熔融温度为700 ℃,熔融时间为15 min的熔融条件,在此条件下进行浸取易于操作,减少了对镍坩埚的损害。采用自制的抽滤装置,即将普通抽滤瓶进行改装,将玻璃砂芯漏斗部分用塑料代替,只需用直径约为40 mm、相当于四分之一张普通滤纸的滤纸进行过滤,过滤时抽滤速度快,滤纸不会穿漏,且吸附的残余酸量很少,易于洗涤和中和。方法用于自制标准样品的测定,回收率在98%～101%之间,相对标准偏差小于5%,能够满足日常分析检测需要。     

The effect of low melting point impurities on the properties of aluminum-lithium alloys

The effect of low melting point impurities, such as sodium and potassium, on the properties and microstructure of Al-Li alloys has been investigated. These impurities have been shown to occur as discrete lenticular particles along grain boundaries. In underaged and peak-aged conditions, the impurity particles are liquid and the toughness and ductility of alloys in this condition were found to be improved by lowering the test temperature below the freezing point of the impurity. In the overaged condition, the sodium and potassium occur as a solid phase and materials in this condition were found to follow the pattern of most aluminum alloys and show a decrease in Charpy impact toughness as the testing temperature was lowered. The addition of sodium and potassium to Al-Li alloys reduced toughness and ductility at room temperature in the range of compositions investigated (up to 476 ppm Na and up to 23 ppm K). Low melting point impurities were found to have little effect on the toughness or ductility of high purity aluminum. The detrimental effects of sodium and potassium on toughness appear to exist only in alloys containing substantial amounts of lithium or magnesium, which break down the relatively harmless solid NaAlSi_x phase which exists in conventional alloys. The loss of toughness due to low melting point impurities was found to be about the amount expected from the calculated reduction in surface energy of a grain boundary crack containing a liquid phase.     

The Cyclandelate Reference Standard (Control 931) of the National Institute of Health Sciences

Raw thiamine hydrochloride material was tested for preparation of the "Thiamine Hydrochloride Reference Standard (Control 931)". Analytical data obtained were as follows: melting point, 242.7 degrees C (decomposition); infrared spectrum, the same as that of the JP Thiamine Hydrochloride Reference Standard; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography (HPLC), a trace amount of one impurity was detected; assay results, 100.4% by UV spectrophotometry and 100.0% by HPLC, respectively. Based on the above findings, the raw material was authorized as the JP Thiamine Hydrochloride Reference Standard (Control 931).     

Features of Structure Formation with Zone Melting of Powder Boron-Containing Refractory Materials

The connection between zone melting production parameters and structure formation of a porous billet with a moving impurity solvent under conditions of a large temperature gradient and continuous heating is established by experiment. Basic specifications for the impurity solvent are formulated. It is shown that during zone melting the impurity solvent added to the original refractory material powder moves in a temperature gradient field through pores of the sintered skeleton activating compaction and recrystallization processes of the original billet at the level of individual particles and with slow rates of molten front movement without entering the molten zone. This makes it possible to combine the operations of preparing highly dense billets and zone melting.     

退火态钽丝表面熔化机理的研究

通过电子探针微区分析,研究钽丝内部的金属杂质铁对退火态钽丝表面的影响。结果表明,钽丝中低熔点金属的存在能导致退火态钽丝的表面熔化,确定了钽丝用钽粉中的铁含量的技术指标,并通过严格的过程控制,降低了退火态钽丝表面熔化的程度。     

火花源原子发射光谱法测定纯金中14种杂质元素

探讨了火花源原子发射光谱法分析纯金中14种杂质元素的分析条件、标准样品及分析样品处理方法,确定了各杂质元素工作曲线线性范围。采用压片方法制备漂移校正样品和纯金试样,用稀盐酸去除试样表面的沾污,工作曲线采用仪器内置的纯金标准曲线,并通过内部质量控制样品和校正样品监控。对于纯金中14种杂质元素的测定,相对标准偏差小于2.76%;测定结果与其他方法相比,吻合较好。     

火花源原子发射光谱法测定银中铜铋铁铅锑钯硒碲

探讨了火花源原子发射光谱法分析银中杂质元素铜、铋、铁、铅、锑、钯、硒和碲的分析条件、样品处理方法, 确定了各杂质元素测定范围。采用对测定结果无明显影响的车床或压样机加工样品表面, 用盐酸(1+9)去除试样表面的沾污, 校准曲线采用仪器内置的纯银标准曲线, 并通过内部质量控制样品和校正样品监控。实验方法用于纯银标准样品中8种元素的分析, 测定值与认定值一致;对银锭样品进行分析, 各元素11次测定结果的相对标准偏差在1.0%~4.0％之间。方法可用于纯银和银锭中包括钯的杂质元素分析。     

An investigation of the electrolytes of aluminum production with the help of physicochemical simulation

A physicochemical simulation of a melting electrolyte is performed with the purpose of developing methods for monitoring the content of impurity elements. A physicochemical model, which allows one to reduce the time and expenses for a chemicoanalytical investigation of the properties of the electrolyte of aluminum baths necessary for the stable performance of electrolysis, is approved. The possibility of determining the phase composition of the main components and impurity elements in the electrolyte that form as the analytical procedures are being carried out at the stages of melting, evaporation, and solidification is shown.     

镁热还原K2ZrF6制备镁锆中间合金

在KCl、NaCl熔剂的保护下,液态Mg能够还原K2ZrF6.通过控制炉料配比、还原温度、还原时间,并用机械正反向交替搅拌,成功地解决了传统生产工艺中渣相与Mg-Zr中间合金难以分离、合金杂质含量偏高、合金成分偏析的难题,获得了高质量的Mg-Zr中间合金.