微波碳热还原含锌铅电炉粉尘

利用含锌铅电炉粉尘、焦炭、无烟煤和烟煤吸收微波能力强的特点,采用微波加热方法对配碳电炉粉尘进行碳热还原。结果表明,选用粒度为-0.096 mm的无烟煤为还原剂,在碳氧比为0.9、还原温度为1 100 ℃、保温时间为15 min的条件下,还原产物中铁的金属化率可达90.33%,蒸发脱锌率为96.26%,脱铅率为88.89%。     

含锌电炉粉尘处理工艺现状及发展

对目前国内外含锌电炉粉尘的性质和处理现状进行了分析和总结。电炉粉尘传统处理工艺都有各自的局限性:填埋法处理无法利用电炉粉尘中的有价金属;钢铁厂循环利用对电炉粉尘铅锌含量要求严格,锌的富集对后续炼铁炼钢工序造成危害,并不能大规模利用;湿法处理电炉粉尘能耗小,但流程长,设备腐蚀严重,目前难以得到大规模工业应用;火法处理虽然生产效率高,操作简单,脱锌率高,原料适应性强,但污染大,能耗高,对环境污染严重。新的处理技术如微波法、真空冶金技术、铝浴熔融法虽具有脱锌率高,更环保等优势,但因设备投资大,技术不成熟等原因,目前很难在工业上得到应用。焙烧转化-分离技术具备流程短,操作简单的优势,是未来处理含锌电炉粉尘的发展方向。     

微波场下冶金含锌尘泥的脱锌效果

研究了在微波场下用C和S iC作还原剂时,氧化锌在精矿粉中的还原率,以模拟钢铁企业冶金含锌尘泥中锌的去除。结果表明:微波处理冶金含锌尘泥,脱锌反应快,效果显著,并且S iC作还原剂时效果较好,得到的氧化锌纯度可达97.7%。因此,微波处理钢铁企业冶金含锌尘泥是可行的。     

微波焙烧锌浮渣脱氯的研究

针对锌浮渣含氯高,现有回收处理过程存在复杂、易造成污染等问题。利用氯化物在微波场中吸波性能好、升温速度快的特点,开展了微波焙烧来脱除锌浮渣脱氯的研究。采用1.5kW箱式微波焙烧反应器,分别考察了焙烧温度、保温时间以及搅拌强度对脱氯效果的影响规律。然后借助扫描电子显微镜(SEM)研究了微波焙烧前后物料成分的变化,并通过氯离子选择电极法分析处理前后锌浮渣物料的氯的含量。结果表明,在焙烧温度为700℃,保温时间80 min,搅拌强度15 r/min的条件下,锌浮渣中氯的脱出率可以达到88%以上,最终氯含量低于0.13%。微波焙烧锌浮渣脱氯效果较好,与传统回转窑、多膛炉焙烧等火法脱氯方法相比,其具有加热快、不易烧结、加热温度低、脱氯效率高、锌损失率低等优点。     

高炉含锌粉尘中铁资源的富集回收

以转底炉工艺技术为基础,采用高温焙烧-磁选分离工艺对济钢高炉含锌粉尘脱锌富集铁进行了实验室研究,考察了还原温度、还原时间及配煤量对含锌粉尘脱锌率、金属化率、磁选精矿产率以及铁回收率的影响。实验结果表明最佳工艺参数为:还原温度1 350℃,还原时间30 min,配煤量4%。在此条件下的脱锌率和金属化率分别为99.75%和99.46%,精矿产率为45.63%,铁回收率为95.76%。     

含锌电炉粉尘配碳选择性还原的实验研究

为实现含锌电炉粉尘选择性还原、有效分离铁和锌资源,采用热力学计算和实验研究相结合,分析电炉粉尘中主要物相的还原分解行为,研究配碳量、反应温度和反应时间对还原产物的影响。结果表明,含锌电炉粉尘配碳选择性还原为铁氧化物和ZnO是可行的;在582~940 ℃之间,可实现铁酸锌的有效分解、ZnO过还原的抑制;随着反应温度增加和反应时间延长,铁氧化物遵循逐级还原规律,配碳量对产物并未产生明显影响;当温度为950 ℃时,ZnO被还原为锌蒸气而挥发,导致产物中锌含量明显降低。在配碳量1/10、反应温度850 ℃、反应时间1 h的优化条件下,ZnFe₂O₄分解率约为70%。     

含锌电炉烟尘氨浸预处理研究

含锌电炉烟尘是炼钢过程中产生的一类具有回收价值的废弃物。针对电炉烟尘成分复杂的特点,结合回转窑—氨浸制取活性氧化锌的工艺,采用碳酸铵作浸出剂,对电炉烟尘进行预处理。在浸出部分锌的同时脱除回转窑不能处理的杂质如钾、钠等,降低了回转窑的处理量。实验结果表明,电炉烟尘中的钾、钠、氯及以氧化锌形式存在的锌进入溶液,其中锌的浸出率为78%,钾、钠、氯的脱除率分别为96%、92%、97%。浸出渣中碱金属含量小于3%,能减少其在后续回转窑处理过程中对炉衬的侵蚀,浸出渣率为50%,同时铁、碳、钙由于未参与反应而得到富集,减少了回转窑的处理量。     

用选矿方法从高炉瓦斯泥中回收铁精矿的研究

介绍了梅山高炉瓦斯泥的性质、试验情况及结果，国内外处理使用含锌高炉瓦斯泥的方法。根据其性质，用选矿方法对高炉瓦斯泥进行了收铁降锌的试验研究。结果表明，无论用弱磁选还是强磁选均能从中回收大部分铁矿物并去除大部分锌，将高锌、低锌物料进行有效分离，铁精矿产率和品位均达到52.00%以上，铁金属回收率70.00%，脱锌率50.00%以上，使除锌后的瓦斯泥可继续作炼铁原料使用。     

新疆某复杂低品位氧化铅锌矿选矿工艺

新疆某氧化铅锌矿,原矿含铅0.14%,含锌2.00%,铅氧化率37.86%,锌氧化率为35.42%,矿石铅锌含量低、氧化率较高,属低品位氧化铅锌矿。采用洗矿脱泥的浮选工艺方案,获得铅品位为43.18%、铅回收率为25.04%的铅精矿,锌品位为42.99%、锌回收率为90.3%的氧化锌精矿,实现铅锌资源的有效回收。     

铁质污染的异极矿浮选富集试验

湖南万寿坪氧化铅锌矿石的锌矿物,氧化率为96%,异极矿占67.85%,次为菱锌矿。锌矿物表面被褐铁矿严重覆盖或污染,与钙镁碳酸盐脉石矿物极为密切。这种难选矿石可不脱泥,经硫化钠(或稀酸)预处理后,用硫化钠脂肪胺盐酸盐乳化剂浮选,粗选时以腐植酸盐抑铁,精选时以硫化钠和碳酸钠组合抑钙镁碳酸盐脉石,原矿含锌15.07%时,可获得含锌40%以上的合格锌精矿,回收率达76%以上。试验了选铅之后直接浮锌和浮碳酸盐脉石矿物后浮锌两方案,并对一些工艺制度作了讨论。     

Microwave caustic leaching of electric arc furnace dust

Electric arc furnace (EAF) dust is a waste product which is generated when steel scrap is melted in an electric arc furnace. It contains high concentrations of iron, zinc and lead. Numerous pyrometallurgical and hydrometallurgical processes have been developed to treat this material. Only a limited number of these have reached commercialization and the majority have been pyrometallurgical. However, the hydrometallurgical processes, such as caustic leaching, offer some potential advantages.In the present research, the application of microwave radiation at 2.45 GHz was employed, as the energy source, in the hydrometallurgical caustic leaching process for EAF dust treatment. The variables which were investigated were: leaching time, microwave power, caustic concentration and the solid to liquid ratio. The experimental results showed that the zinc recovery from the dust increased with a decrease in the solid to liquid ratio and an increase in the microwave power. The optimum caustic concentration for the maximum zinc recovery was 8M. The rates of zinc recovery were significantly higher under microwave conditions as compared to those observed with conventional leaching. Some possible mechanisms to explain this behaviour are discussed.     

Alkaline leaching of zinc from electric arc furnace steel dust

Electric arc furnaces (EAF) generate about 10–20 kg of dust per metric ton of steel, which constitute a hazardous waste, known as EAF dust. This dust contains a remarkable amount of non-ferrous metals, which include zinc, cadmium, lead, chromium and nickel that could be recovered, reducing the environmental impact of the leachable toxic metals, and generating revenue. In this paper, different alkaline leaching techniques were tested in order to dissolve the zinc present in an EAF dust: (i) conventional agitation leaching; (ii) pressure leaching; (iii) conventional leaching following a microwave pretreatment and (iv) leaching with agitation provided by an ultra-sonic probe. Temperature and sodium hydroxide concentration were the variables tested. The highest zinc recovery from the EAF dust, containing about 12% of zinc, was about 74%. This was achieved after 4 h of leaching in a temperature of 90 °C and with a sodium hydroxide concentration of 6 M of the leaching agent.     

Recycling EAF dust by heat treatment with PVC

This study investigated whether polyvinyl chloride (PVC) can be used as an additive for the treatment of electric arc furnace (EAF) dust. The PVC powder was mixed with the dust in order to test the synchronous treatment of two resources: waste PVC and EAF dust. The mixture was made into pellets and subjected to heat at various temperatures. The effects of the heat treatment and heating rate were investigated. The PVC emitted hydrogen chloride gas by pyrolysis and generated chlorides of zinc, lead, and cadmium in the pellets. These chlorides can be recovered by volatilization or leaching after the heat treatment. The residual pellet of this process contained over 45% iron, and it is expected that the residual pellet can be injected into the electric arc furnace.     

国外电弧炉烟尘处理技术现状及发展

综合介绍了国外电弧炉烟尘处理的主要工艺——威尔兹、转底炉直接还原、ZINCEX、EZINEX及MRT(HST)工艺的发展现状。经综合评价后指出：采用先火法后湿法的联合工艺，可以一次回收电弧炉烟尘中全部的铁与锌等有价金属，并得到优质高纯的产品，是将来的发展方向。     

Thermodynamic modelling of the multiphase pyrometallurgical processing of electric arc furnace dust

Electric arc furnace (EAF) dust is produced when automobile scrap is remelted in an electric arc furnace and about 10–20 kilograms are generated per ton of steel. The major elements present in the dust are usually zinc, iron and calcium with smaller amounts of numerous other elements such as lead, copper and nickel. Typically, in the pyrometallurgical EAF dust treatment processes, the lead and zinc are separated as a crude zinc oxide while the iron is generally not worth recovering. Copper and nickel are usually not recovered as they report either to the oxide residue or to any metallic iron that is produced. In the present research, the recovery of the non-ferrous metals in a multiphase system consisting of gas, slag, matte, metal and solid carbon phases was investigated. The equilibrium compositions of the various phases, resulting from the smelting of the dust, were calculated using the SOLGASMIX module of Outokumpu HSC Chemistry. The effects of the following operating variables were investigated; carbon additions, sulphur additions, nitrogen and oxygen additions, temperature and dust composition. The thermodynamic modelling results show that the majority of the non-ferrous metals can be recovered, with the zinc and lead concentrating in the gas phase and the nickel and copper concentrating in the matte phase.     

Application of microwave irradiation to quick leach of zinc silicate ore

A zinc silicate ore was treated with sulfuric acid in a water-starved system in the presence of microwave irradiation. Phase changes occurring during the reaction process were examined by X-ray powder diffraction analysis, and the effect of microwave irradiation time and water amount used on the extraction of zinc, silica and iron was investigated. It is demonstrated that the hemimorphite present in the ore is predominantly changed to ZnSO₄·6H₂O for samples without microwave irradiation and ZnSO₄·H₂O for those with microwave irradiation, respectively. Silica and iron are changed to quartz and Fe(OH)₃. An increase in microwave irradiation time can slightly increase the extraction of zinc and decrease the dissolution of iron. The increase of water amount used can increase the extraction of zinc and considerably decrease the dissolution of silica. Under optimum conditions, the extraction percentage of zinc is 99.08% and the dissolution of silica and iron is as low as 0.30% and 0.10%.     

粉煤热解含尘干馏气两级净化实验研究

为解决粉煤热解过程中的含尘干馏气净化难题,设计了由旋风分离器和颗粒床过滤器组成的高温两级除尘实验装置。基于该装置对旋风分离器和颗粒床过滤器的除尘性能进行了研究,同时探讨了滤料、温度、焦油气等因素对系统除尘性能的影响。结果表明,两级除尘装置中旋风分离器能够完全去除28μm以上的粉尘,颗粒床过滤器能够进一步去除28μm以下的粉尘,整个系统的总除尘效率高达99. 89%。同时,颗粒床过滤器采用半焦作滤料比石英砂具有更高的过滤质量。此外,温度升高会降低旋风分离器和颗粒床过滤器的除尘效率,其对颗粒床过滤器的影响尤为显著。然而,在含焦油气的工况下,部分焦油气会在颗粒床过滤器内部产生冷凝,可以在一定程度上提高颗粒床过滤效率,还可提升焦油品质。     

煤矿除尘技术的研究与展望

矿尘是煤矿安全生产中必须要考虑的因素之一,可导致尘肺病或粉尘爆炸等重特大事故的发生,给一线工人、煤矿企业和国家带来不可估量的灾难和损失。对泡沫除尘技术和风幕除尘技术进行了整理和归纳。泡沫除尘技术的提出极大地改善了喷雾除尘的效率,之后不断研制出新型发泡剂、泡沫发生器以及将泡沫除尘的具体应用等,但是该技术的研究仍存在空缺,成本太高和抑制粉尘的扩散使其无法广泛应用,在对泡沫除尘的研究过程中,应继续考虑如何使其从源头上减少粉尘的产生,同时抑制粉尘的扩散。风幕隔尘集尘系统有抽出式和压入式系统2种结构,在控制风流时,可以达到隔断、引射风流的目的,并且可以对风流增阻。目前,矿井风幕的理论体系与评价指标尚未完善,未来研究开发在完善基础理论研究的同时,将控制噪声技术、节能环保意识与自身的性能相结合。