History of Iron Ore Sintering Recalls Variety of Experimentation

Numerous methods were invented to solve the problem of agglomeration of flue dust and other kinds of ore fines. Methods tried on a large scale were: sintering, briquetting, blocking, and nodulizing. The sintering process introduced in 1900 has developed into the most efficient and economical of these processes.     

Zinc Recovery via the Flame Reactor Process

A major objective of the zinc industry for the 1990s will be to maintain high zinc recovery while eliminating the disposal of copious quantities of hazardous iron residues. The flame reactor process has demonstrated the potential of meeting this objective by either treating the residues or smelting zinc directly. The process has been proven commercially viable for treating flue dusts generated during electric arc furnace steelmaking. Zinc, lead and cadmium are recovered from the dust as a crude oxide for recycle while a nonhazardous slag is produced for sale. Similar products are efficiently produced from electrolytic zinc plant neutral leach and iron precipitation residues. In addition, the reactor shows promise of fulfilling its original objective of being a low-energy primary zinc smelter by fuming and condensing zinc from roasted concentrates.     

常用微粉分离装置的特点

从理论分析入手 ,分别介绍了沸腾冷却床兼做微粒分离装置、单级流幕式微粉分离装置以及多级流幕式微粉分离装置的特点以及在使用中应注意的问题     

Chloride-process treatment of smelter flue dusts

A low-pressure, low-temperature chloride leach process called the Cashman process can be used to extract metals from arsenical flue dusts and residues and fix the arsenic in an environmentally stable form as ferric arsenate (scorodite). The process has been pilot tested in an integrated plant including continuous recycle; during the tests, several tonnes of flue dust were processed. Based on this pilot program, the process was deemed technically feasible, and its products are commercially salable. Residues from this pilot program were also subjected to a long-term stability test.     

黄磷电炉电尘浆提取镓的预处理

根据在电炉还原炼磷过程中,磷灰石中的镓在电尘浆中高度富集,成为可供利用的镓资源,提出了一种提取镓的预处理技术:用浓硫酸熟化电尘,将其中的镓先转化成水溶性化合物,再从预处理物料中浸出镓.考察了预处理过程中电尘的化学和矿物学变化以及影响镓提取率的因素,并给出了适宜的预处理条件;在最佳质量比电尘:水:硫酸=1:1:1,200℃下熟化2 h.实验结果表明,在优化条件下将预处理的电尘在80℃浸出1 h,镓的浸出率可达90%以上.     

Cadmium Purification with a Vibrating Reactor

This paper describes the results of pilot plant testwork on a novel single stage zinc solution purification process using a vibratory reactor. This technique was modified for continuous cadmium cementation. There are distinct advantages to combining an intensely agitated reactor with a high mass of precipitant per unit volume in the form of granular zinc instead of zinc dust, including significant reduction of cementation agent consumption and substantial upgrading of the cadmium cement. This technique has the potential to minimize equipment, reduce plant size, and diminish operating costs.     

Recovery of gallium from phosphorus industry flue

The flue dust generated during electric furnace production of elemental phosphorus was investigated for the recovery of gallium. Then the flue dust was slurried with water and blended with concentrated sulfuric acid, followed by ageing. The gallium in the dust was thereby converted to soluble sulfate. The factors affecting the dust curing were investigated to understand the process chemistry of the pretreatment. The optimal curing conditions are determined as follows: the mass ratio of dust to water and acid is 1 : 1 : 1, ageing temperature and time are 200℃ and 2h, respectively. Almost all the gallium available to acid dissolution in the dust, about 90% gallium, can be extracted by leaching the cured dust at 80℃ for 1h.     

硅业工业硅电炉的收尘设计

根据二期工业硅电炉的烟气特性,设计采用表面冷却器、粗分离器、布袋收尘整套收尘工艺对烟气进行综合治理.结合实际生产运行的情况,阐述了收尘设计的主要参数及主要设备,分析了烟气治理的效果,提出了改进措施.     

大功率密闭直流电弧炉冶炼钛渣烟气净化工艺研究

根据国内引进的第一台30MW密闭直流电弧炉钛渣生产线的工艺流程,对采用云南省钛铁矿冶炼钛渣过程中产生的烟气进行了气体及烟尘的流量、含量、化学成分等分析。由于产生的烟气具有温度高、含尘量大(1.75%~9.60%)、SO2含量低、CO含量高的特点,选择烟气净化设备时,除了处理能力要符合生产要求,还需要考虑粉尘粒径和烟气温度这两个因素,以实现烟气回收利用的目的。经过研究,烟气净化工艺首先对烟气进行直接水冷使烟气降温,然后选用德国进口涤气机对烟气进行精处理,除尘效率可以达到99.983%。处理净化后的烟气,热值高,气体性质稳定,净化后可安全用于无烟煤/钛渣干燥及渣包/铁包的烘烤,实现节能减排的目标;烟尘可以回收利用。     

Purification technology of flue gas from remelting process of aluminum alloy tailings

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钼精矿及烟道灰中铼的测定

介绍了钼精矿及烟道灰中铼的酸溶-萃取光度测定法。对溶样、萃取分离、显色、测定等条件进行了系统的试验研究,确定了铼的最佳测定条件。运用此法进行钼精矿及烟道灰中铼的测定,相对标准偏差 (n=11)均小于3.5%。经与其他实验室不同分析方法 (ICP-AES标准加入法、碱熔-萃取光度法)进行数据比对,结果令人满意     

Hot model studies of the basic oxygen process

A 1/12-size hot model of Jones & Laughlin’s Aliquippa basic oxygen furnace—constructed and operated to simulate plant operations on scrap — hot metal charges—is described. The model, which permits visual observation of reaction zones and data collection without interruption of blowing, can be charged with the same raw materials and blown at specific oxygen rates equivalent to or greater than those used in plant practice. The fluid dynamic factors that govern blowing conditions—principally lance height, blowing rate, and gas velocity—were investigated in the model and are correlated with plant practice.     

The pyrometallurgical processing of galvanizing zinc ash and flue dust

Large amounts of zinc ash and flue dust, containing more than 80% zinc, are accumulated during galvanization processes at the surface of molten zinc bath and in the chimney, respectively. The pyrometallurgical recovery of zinc from both ash and dust samples was carried out, and parameters affecting recovery processes such as time, temperature, and flux percentage were studied.     

沸腾式树脂旧砂热法再生装置的原理及应用

提出了几种树脂旧砂的理论再生加热温度及保温时间,介绍了沸腾式树脂旧砂热法再生装置的工作原理;热法再生系统的工艺流程,工艺布置方案以及实际应用结果。     

Hot Corrosion Mechanism of Steels Exposed to Heavy Metal Chlorides and Sulphates in SO<Subscript>2</Subscript> Environment

Copper flash smelting produces flue dust containing SO₂-rich exhaust gas, causing corrosion problems in the heat recovery boiler of the gas train. In order to understand the corrosion behaviour of boiler steels, conditions of the boiler were simulated in the laboratory. Corrosion damage occurred as chlorine reacted with steel surfaces forming chlorides which deplete the steels from their alloying metals. At the scale/dust deposit interface, where the highest sulphur partial pressures prevail, a sulphate layer covered the mixed oxide and chloride scale. Molten sulphate deposit reduced the metal loss of AISI 304 steel by preventing chromium chloride diffusion away from the steel surface. The Cr₂O₃ scales were quite stable under molten sulphates. The dust deposit melted partially due to the presence of ZnCl₂ in the deposit which initiated corrosion damage by producing a molten salt layer on the steel surfaces bringing it in contact with aggressive compounds in the copper smelter flue dust.     

高钛渣电炉烟气收尘工艺的特点

阐述新立公司高钛渣密闭电炉烟气收尘工艺的特点,该密闭电炉煤气收尘后用于干燥钛铁矿、无烟煤等,达到节能环保的目的.     

转炉煤气干法除尘技术在国内钢厂的应用

转炉干法除尘技术已在我国钢厂推广应用,该技术主要由蒸发冷却器、静电除尘器和煤气冷却器等组成。生产实践表明,该系统运行稳定,净化后的烟气含尘量小于10mg/m3,且运行费用低。     

Corrosion experience with carbon steel in spray absorption FGD plant

Carbon steel is the traditional material for boiler flue gas ducts and stacks. The introduction of flue gas desulphurisation systems in existing power plant units requires major changes in the flue gas system from boilers to the flue stack. In the semidry spray absorption plant at Studstrupværk power plant carbon steel has been used. This concept was chosen to utilize part of the existing carbon steel ducting and avoid the use of expensive high alloyed materials and coating systems. During the first year of operation emission of fine flakes of rust from the ducting and the stack become a major problem. To overcome this, corrosion testings were performed in laboratory and in the plant. The corrosion problems were found to be related to an atmospheric corrosion with hygroscopic chloride containing deposits. The aim of the tests was to establish the critical humidity for corrosion of carbon steel in FGD plant products and deposits. The examinations cover products and deposits from different operational conditions and parts of the Studstrupværk power plant. The laboratory tests were followed by corrosion probe tests in the plant and full scale operation tests with the plant. The results of this programme showed that carbon steel can be used and corrosion can be kept at a very low level by controlling the humidity of the flue gas below 40% RH with fresh water as process water and down to 30% RH with salt water as process water. In practice this has to be controlled by the temperature difference between the flue gas and the adiabatic saturation temperature of the flue gas. Effective insulation of the ducting has been found to be of outmost importance as the humidity should be measured relative to the surface temperature. Experience from the plant shows that the most severe corrosion is found in cold spots.     

High sinter burden experiments in Belgium

At Seraing, tests with low and high sinter burdens have shown a linear relationship between the percent of sinter charged and the coke rate, calorific value of top gases, and amount of flue dust produced. Experiments are compared with the 100-pct sinter burden practice at Dilling and Domnarvet.     

Leaching of gallium from corundum flue dust using mixed acid solution

In order to extract gallium from a high-silica-content flue dust generated in corundum production, a mixed acid solution of H₂SO₄ and HF was used for leaching, and test parameters of the leaching process were optimized. Experimental results show that the leaching rate of gallium was only 38% when H₂SO₄ was used as leaching agent. Composition analysis results of micro areas in this corundum flue dust indicate that the content of gallium in silica-enriched phases was high; this portion of gallium was insoluble in H₂SO₄ solution. The leaching rate of gallium increased significantly with addition of HF due to corrosion of silica. Effects of reaction time, temperature, and concentrations of HF and H₂SO₄ on leaching rates of gallium were investigated. The leaching rate of gallium reached 91% when this corundum flue dust was leached in a mixed acid solution of H₂SO₄ and HF for 4 h, at a temperature of 80 °C, with a liquid-to-solid ratio of 5:1 (mL/g). The optimal concentrations of H₂SO₄ and HF in the mixed acid solution were 1.5 and 6.4 mol/L, respectively.