PHOSPHORUS REMOVAL USING STEEL SLAG

Steel slag is a byproduct produced in large amounts in the steel-making process. It is an important resource that can be effectively utilized. An experiment was described in which steel slag was tested as an adsorbent for the removal of phosphorus from waste water. Phosphorus removal depended on the amount of steel slag added, the pH value, the contact time, and the initial concentration. Under laboratory conditions when the added slag was 7.5g/L, the contact time 2h, and the pH value was equivalent to 6.5, over 99% of the phosphorus was removed; the experimental data on steel slag adsorption of phosphorus in the water fitted the Freundlich isotherm model. Steel slag was found to be very effective in adsorbing phosphorus.

Experimental study on sulfur removal from ladle furnace refining slag in hot state by blowing Air

In view of the present problem of sulfur enrichment in the metallurgical recycling process of ladle furnace （LF） refining slag, a simple and efficient method of removing sulfur from this slag was proposed. The proposed method is compatible with current steelmaking processes. Sulfur removal from LF refining slag for SPHC steel （manufactured at a certain steel plant in China） by blowing air in the hot state was studied by using hot-state experiments in a laboratory. The FactSage software, a carbon/sulfur analyzer, and scanning electron micros- copy in conjunction with energy-dispersive X-ray spectroscopy were used to test and analyze the sulfur removal effect and to investigate factors influencing sulfur removal rate. The results show that sulfur ions in LF refining slag can be oxidized into SO2 by O2 at high tempera- ture by blowing air into molten slag; SO2 production was observed to reach a maximum with a small amount of blown O2 when the tem- perature exceeded 1350℃. At 1370℃ and 1400℃, experimental LF refining slag is in the liquid state and exhibits good fluidity; under these conditions, the sulfur removal effect by blowing air is greater than 90wt% after 60 min. High temperature and large air flow rate are benefi- cial for removing sulfur from LF refining slag; compared with air flow rate, temperature has a greater strongly influences on the sulfur re- moval.

Mechanisms of phosphate removal from aqueous solution by blast furnace slag and steel furnace slag

We report the adsorption of phosphate and discuss the mechanisms of phosphate removal from aqueous solution by burst furnace slag (BFS) and steel furnace slag (SFS). The results show that the adsorption of phosphate on the slag was rapid and the majority of adsorption was completed in 5~10 min. The adsorption capacity of phosphate by the slag was reduced dramatically by acid treatment. The relative contribution of adsorption to the total removal of phosphate was 26%~28%. Phosphate adsorption on BFS and SFS follows the Freundlich isotherm, with the related constants of k 6.372 and 1/n 1.739 for BFS, and of k 1.705 and 1/n 1.718 for SFS. The pH and Ca2+ concentration were decreased with the addition of phosphate, suggesting the formation of calcium phosphate precipitation. At pH 2.93 and 6.93, phosphate was desorbed by about 36%~43% and 9%~11%, respectively. These results indicate that the P adsorption on the slag is not completely reversible and that the bond between the slag particles and adsorbed phosphate is strong. The X-ray diffraction (XRD) patterns of BFS and SFS before and after phosphate adsorption verify the formation of phosphate salts (CaHPO4·2H2O) after adsorption process. We conclude that the removal of phosphate by BFS and SFS is related to the formation of phosphate calcium precipitation and the adsorption on hydroxylated oxides. The results show that BFS and SFS removed phosphate nearly 100%, indicating they are promising adsorbents for the phosphate removal in wastewater treatment and pollution control.

Smelting chlorination method applied to removal of copper from copper slags

In order to reasonably utilize the iron resources of copper slags, the smelting chlorination process was used to remove copper from copper slags. Higher holding temperature and O2 flow rate are beneficial to increasing copper removal rate. However,the Cu2O mode is formed by the reaction of surplus O2 and CuCl with O2 flow rate increasing over 0.4 L/min, causing CuCl volatilization rate and copper removal rate to decrease. The resulting copper removal rate of 84.34% is obtained under the optimum conditions of holding temperature of 1573 K, residence time of 10 min, Ca Cl2 addition amount of 0.1(mass ratio of CaCl2 and the copper slag) and oxygen flow rate of 0.4 L/min. The efficient removal of copper from copper slags through chlorination is feasible.

Study on the removal of Hg^0 from flue gas by coal dry powder gasification coarse slag

The prevention and treatment of mercury in coal-fired power plants has always been the focus and difficulty.How to control the pollution of mercury to human body and ecological environment quickly and effectively is a hot research topic nowadays.As a low cost and potential adsorbent,there is a huge space for the development of coal dry powder gasification coarse slag.In this paper,Mercury osmotic tubes are heated by water bath tank as mercury source,and the scavenging effect of adsorbent on Mercury monomer under different influence conditions is explored.The adsorbent plays an important role in adsorption of mercury monomer because of its special active sites on the surface.The reason is that the adsorbent surface is rich in carboxyl group,hydroxyl functional group,combined with mercury to form complexes.This shows that chemical adsorption facilitates the adsorption process.

Removal Rate of Phosphorus by Different Constructed Wetland Substrates

[ Objective] The study aimed to discuss the removal rate of phosphorus by different constructed wetland substrates. [ Methed] Based on static experiments, we analyzed the removal rate and characteristics of phosphorus by different constructed wetland substrates like steel slag, cin- der slag, shale, boiler slag, soil and gravel. [ Result~ The maximum adsorption of phosphorus by various substrates showed as follows, steel slag 〉 cinder slag 〉 shale 〉 boiler slag 〉 soil 〉 gravel. When the initial concentration of phosphorus was 5 mg/L, the removal rate of phosphorus by the steel slag, cinder slag, shale, boiler slag, soil and gravel was 99.76%, 85.8%, 71.2%, 63.0%, 46.8% and 11.7% respectively. It is suggested that shale and boiler slag can be used as the substrate of subsurface-flow constructed wetlands; cinder slag can be chosen as a renewable sub- strate for intensifying phosphorus removal; steel slag could be used at the end of subsurface-flow constructed wetlands for treating TP in outflows. [Concluslon] The research could provide theoretical references for choosing a suitable substrate for constructed wetlands to remove phosphorus in future.

铝粉还原污酸中砷新工艺研究

由于硫化精矿中砷含量越来越高,致使烟气处理过程产生的污酸中砷含量也越来越高,同时污酸中含有铜、铁等有价金属。目前污酸除砷方法多以除砷为目的,形成的含砷渣属于危废,还需要二次处理。本研究研发了还原除砷新工艺,首先向污酸中加入硫化砷渣进行脱铜预处理并回收铜,然后用铝粉还原脱铜后液中的砷回收砷,最后向脱砷液中加入硫酸钾回收铝,还原后液回收还原剂后采用两段中和法处理。试验研究结果表明,在加入铜离子摩尔量1.1倍的硫化砷渣、反应温度85℃、反应时间3 h的条件下,污酸中的铜含量由2000 mg/L降至196 mg/L,硫化铜渣返熔炼配料系统;在还原温度70℃、还原时间2 h,还原剂用量1.8倍的条件下,砷的还原率大于96%,还原后液中的砷含量低于300 mg/L,得到的砷渣品位大于95%,可用于后续制备高品位单质砷;在硫酸钾用量1.1倍、反应温度常温、反应时间2 h的条件下,溶液含铝3.6 g/L,得到的明矾可达到《工业硫酸铝钾》(HG/T2565—2007)一等品标准。该方法除砷效果好,且能将污酸中的砷转变为具有经济价值的砷产品,还不会产生硫化氢气体,具有应用推广价值。

铜底吹熔炼过程中Pb、Zn、As分布影响机理分析

探究底吹熔炼过程中Pb、Zn、As等杂质元素在产物中的分布特征,以及熔炼参数与杂质元素分布规律的关系,对低品位、高杂质复杂铜精矿的冶炼具有重要意义。本文采用热力学计算软件Factsage理论分析与实际生产数据分析相结合的方法,探讨了Pb、Zn、As在产物中的分布特征及其影响机理,得到以下主要结论。温度升高,有利于Pb、Zn挥发进入烟尘降低其在渣和铜锍中的占比,也有利于促进渣中As向烟尘中转化脱除,但会导致As在铜锍中占比增加;渣铁硅比增加,会使得Pb、Zn在渣中分布占比逐渐降低,在铜锍和渣中占比逐渐升高,而As在渣中的占比会增加;渣中CaO含量升高,会使得Pb、Zn在渣中分布占比降低,在烟尘和铜锍中增加,As在渣中的占比会增加,在烟尘中占比降低;实际生产操作中,可通过提高冶炼温度促进部分杂质元素挥发,在适当降低渣铁硅比提高Pb、Zn脱除率的同时,可配合添加CaO促进As向渣中迁移。实际生产数据统计表明,Pb在铜锍、渣、烟尘中的分布占比分别为23.86%、33.12%、43.02%,Zn分别为4.47%、88.54%、6.99%,As分别为16.58%、15.34%、68.08%。

超声波强化硫酸洗涤单宁锗渣

锗具有特殊性能,已被许多国家划分为战略性资源,在多个领域具有不可替代的作用。在氧化锌烟尘浸出过程中,由于杂质金属与锗会一同进入溶液,并与单宁酸共同发生络合反应,导致煅烧后所获得的锗精矿品位低、杂质含量高,对于后续的氯化蒸馏工艺十分不利。因此在单宁锗渣煅烧前,去除其中杂质金属对于锗资源化利用具有重要意义。本研究以单宁酸沉锗所得单宁锗渣为原料,以硫酸溶液为洗涤剂,通过引入超声波强化去除其中的主要杂质金属锌与铁,实现锗富集。通过单因素试验研究了酸洗过程中固液比、硫酸浓度、酸洗时间、酸洗温度以及超声波功率对锌与铁去除率的影响。结果表明,在最佳工艺条件:H_(2)SO_(4)浓度0.3 mol/L、固液比300 g/L、酸洗时间40 min、酸洗温度50℃、搅拌速度300 r/min、超声波功率300 W的条件下,锌与铁的去除率分别为86.74%与85.68%。对洗涤除杂后的单宁锗渣进行煅烧,结果表明超声波强化酸洗生产的锗精矿品位高达25.65%,与未洗涤以及常规酸洗相比,超声波强化酸洗生产的锗精矿品位分别提高了约22%、15%,绿色、高效地除去了单宁锗渣中的大部分杂质金属,显著提高了锗精矿的品位。

赤泥和铜渣基功能型陶粒的磷吸附性能研究

利用固体废物赤泥和铜渣作为原料制备功能型陶粒,研究了功能型陶粒对磷的吸附性,考察了陶粒烧制温度、添加剂用量、陶粒投加量、初始pH、吸附反应时间和磷初始质量浓度对除磷率的影响。结果表明,陶粒的最佳配比为:赤泥、铜渣与膨润土的质量比为5∶1∶4,CaCO_(3)添加量为30%。最佳制备工艺为:将原料混合的生球烘干,在400℃下保温10 min后,继续升温至1100℃保温30 min。对于100 mL磷初始质量浓度为2μg/mL磷溶液,在pH为2,陶粒投加量为9 g/L,吸附反应时间为12 h,对磷的吸附效果最佳,除磷率为96.67%。X射线衍射(XRD)和扫描电镜-X射线能谱(SEM-EDS)分析结果表明,最佳条件下制备的陶粒主要矿物成分为钙铁榴石、镁黄长石和钙铝黄长石。

微波强化中和铅锌冶炼渣干燥机制研究

针对现行铅锌冶炼渣干燥周期长、过程污染大等问题,本文提出微波强化干燥新工艺,在分析原料物性状态的基础上,对中和铅锌冶炼渣高温介电及微波干燥影响因素进行分析,明确了微波强化中和铅锌冶炼渣干燥过程机制。结果表明,中和铅锌冶炼渣中含有结晶水的物相为CaSO_(4)·0.5H_(2)O,自由水含量为30.2%,结晶水含量为7.2%,自由水与结晶水的吸波性能相似,且明显优于渣中其他物相;在粒径8 cm、厚度2.2 cm、微波功率700 W、干燥时间15 min条件下,微波干燥中和铅锌冶炼渣效果最优,自由水完全去除,结晶水去除率达到53.06%,总失水率为34.02%;微波干燥中和铅锌冶炼渣时,会引起中和铅锌冶炼渣的破裂分层,有助于实现快速高效干燥;相较常规干燥,微波干燥1 kg中和铅锌冶炼渣节约能耗16.98%(630 kJ),比常规多脱除5.40%的水分,干燥时间缩短87.5%。本论文所建立中和铅锌冶炼渣干燥技术具有明显优势。

碱熔融复合改性钢渣处理铅离子废水的试验研究

采用复合改性剂〔NaOH或Al(OH)_(3)+粉煤灰〕在高温下对钢渣进行改性,探究了碱熔融温度、碱熔融时间及碱掺量等因素对改性钢渣吸附铅离子性能的影响,并结合XRF、XRD、SEM和BET等测试方法,对改性钢渣的化学成分、矿物组成、微观结构及孔径进行分析,并考察了最优条件下制备得到的改性钢渣的重金属浸出毒性,对铅离子吸附的再生性及选择性。研究结果表明,在碱熔融温度700℃,碱熔融时间4 h,钢渣、粉煤灰和碱性改性剂Al(OH)_(3)质量比100∶10∶20条件下,吸附铅离子效果最佳。改性钢渣没有生成新的晶体,只是破坏了钢渣中原有的晶体结构,生成了具有一定活性的多孔硅酸铝盐,表面松散堆积细小熔融颗粒,孔径集中分布在5~20 nm,在孔的吸附、化学沉淀和离子交换等反应共同作用下,对废水中铅离子的吸附率达98.15%,且具有较好的再生性和选择吸附性,是一种绿色安全的重金属离子吸附剂。

秸秆-钢渣混合填料对低C/N比污水脱氮研究

为探讨作物秸秆和钢渣对低C/N比污水脱氮的影响,本研究分别以空白(CK)、小麦秸秆(W组)、水稻秸秆(R组)、小麦秸秆+钢渣(WF组)、水稻秸秆+钢渣(RF组)、钢渣(F)为填料,在厌氧循环系统中对C/N比为0.23~0.93的污水进行处理,探究6种不同的填料-系统对NO3-N的去除效果。结果表明:W组、R组、WF组和RF组的NO_(3)^(-)-N去除率分别为94.99%、86.70%、98.75%和94.70%;相比于WF组和RF组填料系统,纯秸秆填料系统(W组和R组)对污水中NO_(3)^(-)-N的去除速度更快,但在处理过程中的可溶性有机碳(DOC)浓度更高;WF组和RF组钢渣中含铁化合物的释放及转化会消耗有机质,因此其DOC浓度保持在较低水平,避免了因DOC浓度过高而引起的二次污染问题。综合考虑,小麦秸秆+钢渣混合填料在脱氮过程中能够在保持高效脱氮的同时避免出水二次污染问题,更适用于低C/N比污水的脱氮。

精炼渣酸性氧化浸出制备黑铜电解液实验

这是一篇冶金工程领域的文章。研究了双氧水氧化酸性浸出法从高铜高锡阳极炉精炼渣中脱除铜制备黑铜电解液。主要考查了双氧水用量、反应温度、硫酸浓度、固液比和反应时间等因素对铜脱除效果的影响。结果表明,在精炼渣20.0 g,2.0 mol/L硫酸溶液200 mL,S/L=1/10,浸出温度65℃,双氧水用量10.0 mL,搅拌速度400 r/min和浸出时间60 min时,Cu、As的平均浸出率分别达到88.98%、87.33%,而Ni和Sn的浸出率仅为7.72%和1.34%,浸出液中铜离子浓度为48.48 g/L,可用于黑铜电解液的补充液。

风冷式干除渣系统在1×330 MW机组中的应用与优化改造

东海热电330 MW机组采用传统的水力除渣方式,存在水资源浪费、能耗高、安全性差、维护费用高等问题。对电厂生产过程中炉渣的排放方式及提高炉渣的综合率方面进行研究论证,将水力除渣系统改造成风冷式干除渣系统,改造后简化了排渣系统,提高了能源利用率及锅炉的效率。风冷式干除渣系统灰渣燃烧充分、含碳量低,保留了炉渣的活性,利于灰渣综合的利用,提高了社会效益及经济效益,对提高整个电厂的经济运行水平具有非常重要的意义。

顺层钻孔螺旋排渣孔口“三防”装置研制及应用

为减少瓦斯抽采钻孔施工过程中的瓦斯风险和粉尘危害,防止摩擦静电或火花进入抽采系统,针对王坡煤矿顺层钻孔螺旋排渣施工工艺特点,研制了由钻孔气渣分离箱、钻孔封孔套管、二次气尘分离箱及相关配套组件组成的新型“三防”装置,进行了现场应用试验,大幅提高了钻孔施工的安全性,降低了钻场作业人员的瓦斯、粉尘风险。该装置投入应用后巷道瓦斯浓度降低率达77.8%、钻孔孔口瓦斯浓度降低率达99.1%、孔口下风侧5 m处降尘率达92.5%以上。

污水处理中的硫化法除砷

砷在自然界中普遍存在,砷的化合物有很强的毒性,进入环境中会对人们的生产生活造成很大的危害。介绍了中和硫化法、浮选硫化法、重金属捕集剂硫化法、微生物硫化法的除砷工艺,同时分析了硫化法除砷的特点,综述了当前国内外硫化法除砷技术的研究现状,并对砷治理的发展趋势及应用前景进行了分析和展望。

除渣装置在煤化工领域中的实践应用

现阶段国内煤化工领域发展迅猛,相关项目随之日渐增多,而煤化工项目种类较多,常见的有水煤浆气化炉与干煤粉气化炉,但无论哪种气化炉,只要其使用的原料以煤为主,则必然要安装除渣装置以确保设备的有效运行。着重探讨该类装置在煤化工领域的实践应用,先行明确除渣装置的具体工艺流程,随后以此为基础,探讨其在煤化工领域应用路径,随后以具体案例来进一步说明其应用过程,以期为提升除渣装置在煤气化领域中的应用安全性与平稳性提供有效借鉴。

无水砂卵石地层隧道内长距离大管棚施工技术

无水砂卵石地层中开挖易引起塌方,可采用大管棚支护。然而该地层中管棚打设困难,长距离打设还存在精度低、地层扰动大、变形大的问题,且缺乏经验。基于此,以北京地铁工人体育场站暗挖工程为背景,通过多组大管棚打设试验,比选得出打设长40.2 m的大管棚时可采用冲击旋转跟管钻进、高压风排渣的方法;据此调整确定了超长92.9 m大管棚打设所需设备和参数,并在现场成功实现了单根长度12.7~92.9 m、总长度58331 m的大管棚的打设,且打设精度高、质量好、地表变形小。最终提出隧道内无水砂卵石地层中超长大管棚打设施工工艺和重点控制措施,研究成果可为类似工程提供指导,弥补大管棚技术在无水砂卵石地层应用中的不足,具有重要工程意义。

钢包包底结构优化及铸余量控制实践

钢包铸余量控制不当时,合格钢水易变成渣钢导致铸坯收得率降低。包底工作层冲击区凹陷导致铸余量增加,且其在钢包周转过程中难以控制。在本工作中,通过采取钢包水口附近增加御渣区、座砖胎模结构优化、包底工作层冲击区及时修补等控制措施,使钢包铸余量降低了41.8%,经济效益显著,为钢厂解决浇铸尾期大包下渣量问题提供参考。