Resource utilization of slag from desulphurization and slag skimming:A comprehensive recycling process of all components

In order to make the slag from desulphurization and slag skimming(SDSS)to be comprehensively recycled and utilized,a combined process of beneficiation and building materials preparation was proposed to recover iron from SDSS,meanwhile to apply the remaining slag tailings as cement admixture.From this process,three iron-rich products were recovered in stages by clean gravity-magnetic separation,slag tailings were left.Slag powder was prepared by ultrafine grinding of slag tailings.The stability,setting time and cement mortar strength of the slag tailings cements(STC)which were mixed with Portland cement and slag powder were studied respectively.The results showed that a proper overall performance still could be obtained at the slag powder content of 30%.Chemical composition analysis,X-ray diffraction(XRD)analysis,metallographic microscope and scanning electron microscope(SEM)analysis were employed to assess the characteristics of the SDSS and the products obtained from the whole process.The results indicated that the three iron-rich products could be used as a raw material for steelmaking and ironmaking and the relatively large amount of calcium silicate(C_(2)S)and tricalcium silicate(C_(3)S)in the slag tailings make the addition of slag powder into the Portland cement feasible.

KINETICS OF DESULPHURIZATION IN PERMANENT CONTACT OF SLAG AND STEEL

The curve of % S vs reaction time is described quantitatively based on the electrochemical model directly deduced from the principle of electrochemistry as well as the given method for calculating the initial oxygen potential along slag/steel interface.The calculated data is in good agreement with the experimental results. During desulphurization,both L_s~* and L_s,the sulphur partition along the interface and that in the bulk,go up in association with the descending of oxygen potential along interface. The plot of L_s~* against reaction time follows a parabolic curve,while that of L_s is of hyperbola type.Correspondingly,on curves of driving force parameter vs reaction tone,either calculated or experimental,a hump occurs.

Adsorption of Pb^2+and Cu^2+with Unburned Desulphurization Slag Modified Nickel Slag

Desulphurization slag modified nickel slag adsorbent was prepared by unburned forming technology. The structure of the sample was characterized by BET,XRD,IR,SEM and EDAX. The adsorption performance of Pb^2＋ and Cu^2＋ onto the resultant adsorbent from aqueous solution was studied. Results indicated that the adsorbent possesses a network pore structure formed by the AFt and C–S–H through cross lapping; the adsorbent contains a large number of Si–OH and Al–OH functional groups. The presence of functional groups not only provides abundant adsorption sites for Pb^2＋ and Cu^2＋,but also improves the adsorption performance of Pb^2＋ and Cu^2＋ from waste water through the complexation of heavy metal ions. The result of specific surface area analysis showed that the adsorbent sample possesses mesoporous structure and the BET specific surface area is 27.15 m^2/g. The solution p H values for the adsorption of Pb^2＋ and Cu^2＋ were optimized to be 6 and 5.5,respectively. The adsorption capacities of Pb^2＋ and Cu^2＋ gradually increase,whereas the removal rates of the two metal ions decrease with increasing the initial concentration of simulated solution. The resultant adsorbent gives a higher adsorption capacity for Cu^2＋ than for Pb^2＋ in the single ion solution. However,it shows preferential adsorption of Pb^2＋ rather than that of Cu^2＋. Meanwhile,results of recyclability indicate the remarkable regeneration capacity,re-adsorption ability and reusability performance of the adsorbent sample.

The Ionization Theory of Desulphurization of the Panzhihua Blast Furnace Slag

With the proper choice of the ion species present in the Panzhihua blast furnace slag, the sulphur partition ratio was calculated based on the ionization theory of the slag. It can be concluded that TiO_2 reacts as an acidtc oxide and the Panzhihua ore or concentrate cannot be treated as a semi-self-fluxing ore.

Vacuum Treatment for Simultaneous Desulphurization and Dephosphorization of Hot Metal and Molten Steel

The vacuum treatment for simultaneous desulphurization and dephosphorization of hot metal and molten steel with pre-melted CaO-based slag was carried out.For pre-treatment of hot metal,both desulphurization and dephosphorization are improved with the increase of CaO in slag,but deteriorated with the increase of CaF2 in slag.The average desulphurization and dephosphorization rate is 68.83 % and 78.46 %,respectively.For molten steel,the substitution of BaO for CaO in slag has minor effect on simultaneous desulphurization and dephosphorization.The desulphurization and dephosphorization rate is higher than 90% and 50% respectively with the lowest final sulfur and phosphorus mass percent being 0.001 2% and 0.010%,respectively.The overall effect of simultaneous desulphurization and dephosphorization of molten steel is better than that of hot metal.

Designing Evolutionary Wavelet Neural Network for Estimating Foaming Slag Quality in Electric Arc Furnace Using Power Quality Indices

In the present study,a novel approach based on an evolutionary wavelet neural network(EWNN)is proposed to estimate the slag quality in an electric arc furnace(EAF)employing power quality indices.In the EWNN,an evolutionary method is applied to train the parameters for a combination of neural networks and wavelets.I For this purpose,all of the electrical parameters for six melting processes are measured with a power quality analyzer,attached to the secondary component of an EAF transformer at a Saba steel complex,to estimate the foaming slag quality.Experimental results on various combinations of measured electrical parameters,applying the designed EWNN estimator,demonstrate that utilizing five leading indicators leads to the highest precision.The obtained 99%accuracy for estimating the foaming slag quality by EWNN compared to the other methods illustrates the proposed method's efficiency.

Slag foaming experiments in EAF for stainless steel production

The foaming slag practice can effectively solve the problems existing in EAF smelting of stainless steel, such as high electrical consumption ,high refractory consumption and long tap to tap time. In this paper, theoretical analyses were made on the technical difficulties and development feasibility of the technology. Slag foaming experiments were performed in a 10t EAF where crude stainless steel with a Cr content of 13% - 15% and a carbon content of 1.5% - 2.5% was smelted and special foaming pellets were added to release additional gas for better foaming. Good foaming slag was observed with the electric arc fully covered by the foam when the content of Cr2O3 is between 7% - 12%. The industrial scale experiments were performed in a 110 t EAF by the use of the same foaming pellets. Compared with the traditional operation, these experiments resulted in better foaming effects.

Influence of aluminium nitride as a foaming agent on the preparation of foam glass-ceramics from high-titanium blast furnace slag

To effectively reuse high-titanium blast furnace slag （TS）, foam glass-ceramics were successfully prepared by powder sintering at 1000℃. TS and waste glass were used as the main raw materials, aluminium nitride （AIN） as the foaming agent, and borax as the fluxing agent. The influence of the amount of A1N added （lwt%-5wt%） on the crystalline phases, microstructure, and properties of the produced foam glass-ceramics was studied. The results showed that the main crystal phases were perovskite, diopside, and augite. With increasing A1N content, a transformation from diopside to augite occurred and the crystallinity of the pyroxene phases slightly decreased. Initially, the aver- age pore size and porosity of the foam glass-ceramics increased and subsequently decreased; similarly, their bulk density and compressive strength decreased and subsequently increased. The optimal properties were obtained when the foam glass-ceramics were prepared by adding 4wt% AIN.

Study on Foaming Behaviour of Molten Slag during Smelting Reduction with Iron Bath

The molten slag in smelting reduction with iron bath has peculiar behaviour for its high FeO concentration. Slag foaming is effected by the concentration and reduction rate of FeO, basicity of slag and temperature. Addition of granulated coke can greatly decrease slag foaming extent in the process of smelting reduction with iron bath. The anti-foaming capacity of granulated coke is the best when the ratio of coke used for coke layer to total coke used in smelting reduction is controlled at about 20%.

Foaming Behavior in Molten Slag Caused by Decomposition of Carbonate Minerals

The average foam life is proposed as an index to the foaming behavior in molten slag. The molten slag system of Na2B4O7-CaO-MgO is foamed by the gas from the thermal decomposition of carbonate minerals as the foamer. The experimental results show that foamer type and particle size have influence upon the average foam life of slag. The concentration of CaO and MgO in molten slag not only varies the physical properties of melt but also influences directly the decomposition rate of carbonate and the bubble size of gas, thus playing an important role in foaming and to foam stability of slag.

利用电石渣替代水泥开发固碳胶凝材料

本研究利用电石渣替代部分水泥,制备新型固碳胶凝材料,研究了不同电石渣含量的胶凝材料对600 kg/m3等级泡沫混凝土的基础性能及固碳性能的影响。研究表明:电石渣的掺入导致泡沫混凝土气孔变大,28 d抗压强度先升高后降低,保温性能提高;当电石渣取代10%水泥,制备出的泡沫混凝土干密度为595 kg/m3,28 d抗压强度比未掺加电石渣的提高4.2%,达5.0 MPa;当电石渣取代50%水泥,制备出的泡沫混凝土导热系数比未掺加电石渣的降低17.1%,为1.131 W·m-1·K-1。电石渣掺加有利于改善泡沫混凝土收缩,当电石渣掺量增加,泡沫混凝土先呈现收缩减小后出现膨胀。碳化养护不仅能够固化封存CO_(2),还能提高泡沫混凝土的力学性能与保温性能。电石渣掺量越高,泡沫混凝土固碳能力越强,电石渣掺量为50%时,CO_(2)的捕获量达到46.02 wt%。

碱激发矿渣基泡沫混凝土的制备及其封存CO_(2)可行性研究

随着工业化进程的不断推进,工业固体废弃物的排放量逐年增加,以工业固废为主要原料制备泡沫混凝土并将其用于CO_(2)封存,对实现工业固废的资源化利用和CO_(2)的经济、高效封存具有重要意义。本文以高炉矿渣为原料,选用NaOH为碱激发剂,硬脂酸钠为稳泡剂,十二烷基硫酸钠(C12H25NAO4S,SDS)为发泡剂,制备了高孔隙的泡沫混凝土。探究了不同NaOH用量对矿渣基泡沫混凝土综合性能及封存CO_(2)性能的影响。实验结果表明,随着NaOH用量的增加,泡沫混凝土的干密度逐渐增加,抗压强度先增大后减小。泡沫混凝土的内部孔隙分布不均匀,孔隙率大。SEM结果表明,当NaOH用量过高时泡沫发生破裂连通。XRD结果表明,矿渣基泡沫混凝土水化产物主要是C—S—H凝胶和Ht物相,Ht物相的层状结构使得材料的孔壁不够致密,从而影响材料的力学性能。TGA结果表明,碳化过程中水化产物有效吸收CO_(2)转化成以CaCO3为主的碳酸盐,NaOH用量12%时,CO_(2)的封存量最高为89.74 kg/m^(3)。

基于光谱学分析的硬质聚氨酯泡沫/钢渣/次磷酸铝复合材料阻燃机理研究

硬质聚氨酯泡沫(RPUF)的优异性能使其在各领域被广泛应用,但本身的易燃性为其在应用过程中埋下了巨大的安全隐患。钢渣(SS)作为提炼铁精矿后排放的固体废弃物,因其综合利用效率低下而造成一系列环境污染问题。为提高RPUF火灾安全性和钢渣的附加值,将SS和次磷酸铝(AHP)引入到RPUF中,采用一步全水发泡法,制备一系列阻燃RPUF(FR-RPUF)复合材料。利用射线荧光光谱分析(XRF)探究了SS的化学成分,并系统研究了SS/AHP对FR-RPUF复合材料的微观形貌、热稳定性、阻燃性能以及气相产物的影响。XRF测试表明:钢渣的化学成分主要是CaO、SiO_(2)、Al_(2)O_(3)、Fe_(2)O_(3)、SO_(3)、MgO,以上金属氧化物能够作为协效剂促进聚合物成炭,并覆盖在材料表面阻隔燃烧热,在凝聚相达到阻燃目的。扫描电镜(SEM)测试表明:SS/AHP与RPUF基体的相容性较差导致FR-RPUF的泡孔出现不同程度的破损。阻燃测试表明:RPUF-1、RPUF-4、RPUF-5的极限氧指数分别为24.2 vol%、23.4 vol%、19.7 vol%,说明SS和AHP存在一定的协效阻燃作用,且RPUF/SS/AHP复合材料全部通过UL-94 V-0级别,满足外墙保温材料使用要求。热重-红外分析(TG-FTIR)测试表明:SS/AHP并未改变RPUF的降解过程,气相产物主要为碳氢化合物、羰基化合物、氨基甲酸酯、CO_(2)、异氰酸酯化合物、芳香族化合物、氰化氢、羰基化合物和酯类。对典型挥发性产物进一步分析发现,AHP和SS的加入促进RPUF基体早期降解。拉曼测试表明:当SS/AHP加入到RPUF后,RPUF-4的D峰与G峰的峰面积比(I_(D)/I_(G))值最小,表明SS/AHP的加入提高了FR-RPUF复合材料炭渣的致密性、石墨化程度。结合上述分析提出阻燃机理:首先AHP吸热分解,降低了火焰周围的温度,其分解的PO·自由基捕获游离的HO·抑制连锁反应,分解产生的焦磷酸铝与炭渣覆盖在基体表面,抑制了火焰和可燃气体的扩散。AHP分解产生的PH3遇氧气生成酸性物质(磷酸和聚磷酸),促进了RPUF脱水成炭,并且钢渣中的矿物成分会与磷酸或聚磷酸反应,形成致密炭层,与AHP共同发挥协效阻燃作用。研究为SS和AHP复配阻燃硬质聚氨酯泡沫材料提供理论依据和实验基础。

Experimental Research on Refining Slag Systems Containing BaO for Ultra-Low Sulphur Steel

The experimental research on refining slag systems for ultra-low sulphur steel was carried out in a 10 kg induction furnace.It was proved that sulphur element in molten steel can be removed to less than 5×10^(-6) by adding CaO-Al_2O_3-SiO_2-MgO-CaF_2 slag on the surface of molten steel and feeding CaO-BaO-CaF2 wire into molten steel.And L_s,which is the coefficient of sulphur between slag and molten steel,that is ω(s)/ω[s],increases by increasing I(I = ωBaO/ωCaO).When I=5/3,L_s can be up to its maximum of 633.The CaSi is effective for deep desulphurization,especially when it is added to the slag of wire feeding.

粉煤灰 - 锂渣基发泡陶瓷的制备及性能研究

为制备低成本兼具高孔隙率与高压缩强度的发泡陶瓷,以粉煤灰、锂渣、长石、滑石和碳化硅为原料,经1180、1200、1220、1240℃分别保温10、20、40、60 min烧结制备发泡陶瓷试样。主要研究了锂渣的掺量(质量分数分别为0、10%、20%、30%)对试样物相组成、显微结构、孔隙率及压缩强度的影响。结果表明:1)随锂渣掺量的增加,发泡陶瓷的孔隙率增加,体积密度降低,压缩强度波动;2)锂渣中丰富的钙、硫成分,可发挥助熔剂和发泡剂作用,降低烧结温度,提高发泡陶瓷的孔隙率,改善气孔圆整度,提高压缩强度;3)当锂渣掺量为20%(w)时,经1220℃保温20~40 min烧结所得发泡陶瓷的体积密度为0.32~0.40 g·cm^(-3),孔隙率为84.4%~87.6%,压缩强度为1.51~2.35 MPa。

Recovery of bismuth and antimony metals from pressure-leaching slag

The leaching behavior of metals from a pressure-leaching slag was investigated using a desulphurization-leaching-hydrolysis process for the recovery of bismuth and antimony.Various parameters were studied,including the amount of acid added,temperature,time,addition of NaCl and solid-liquid ratio in the leaching process.The experimental results show that the contents of bismuth and antimony are mostly enriched in the process of kerosene desulphurization.More than 98% Sb and 96% Bi are extracted under the determined conditions.In the process of hydrolysis,the precipitation rates of bismuth and antimony are 97.80% and 94.59%,respectively.Under the optimum experimental conditions,the recovery rate of bismuth and antimony can be up to 95.80% and 90.80%,respectively.

钢渣细骨料泡沫混凝土制备及抗压强度计算

为实现钢渣资源化利用,以钢渣作为细骨料,采用不同钢渣粒径、钢渣取代量和水胶比制备了钢渣泡沫混凝土试块,通过7 d无侧限抗压强度确定出最优配合比为1.18 mm钢渣粒径、20%(与水泥质量比,下同)钢渣取代量、0.45水胶比。根据分形理论建立了最优配合比下钢渣泡沫混凝土抗压强度与孔隙率的关系式,试样的分形维数D可由盒计数法算出。此分形模型计算的抗压强度预测值与试验值吻合度较高。通过对比其他文献中泡沫混凝土抗压强度的实测值,证明了分形计算模型能够准确预测出泡沫混凝土的抗压强度,具有良好的应用前景。

一种再生复合相变材料泡沫玻璃的制备与性能测试

为减少建筑材料能耗,试验通过固废物水淬渣和陶瓷废料,结合氧化铝和硼砂,制备一种泡沫玻璃材料,并研究其强度和保温性能。结果表明,该泡沫玻璃材料的最佳配方为:在900℃发泡温度条件下,水淬渣、陶瓷废料和纯碱份数比例固定为40∶60∶10,氧化铝和硼砂添加量分别是4%、8%。此时,制备的泡沫玻璃材料抗压强度为9.38 MPa,导热系数为0.411 W/(m·K),均符合建筑保温材料要求。综上,试验中的泡沫玻璃材料有着良好的强度和保温性能,是一种绿色环保的建筑节能材料,可以适用于建筑外墙等。

Wettability of Molten Steel/Na2O-Li2O-SiO2-B2O3 Slag System

The vacuum treatment for simultaneous desulphurization and dephosphorization of hot metal and molten steel with pre melted CaO based slag was carried out. For pre treatment of hot metal, both desulphurization and dephosphorization are improved with the increase of CaO in slag, but deteriorated with the increase of CaF 2 in slag. The average desulphurization and dephosphorization rate is 68 83 % and 78 46 %, respectively. For molten steel, the substitution of BaO for CaO in slag has minor effect on simultaneous desulphurization and dephosphorization. The desulphurization and dephosphorization rate is higher than 90 % and 50 % respectively with the lowest final sulfur and phosphorus mass percent being 0 001 2 % and 0 010 %, respectively. The overall effect of simultaneous desulphurization and dephosphorization of molten steel is better than that of hot metal.

小颗粒石灰石与石灰化渣脱磷效果试验研究

为了探究转炉喷吹小颗粒石灰石炼钢的可行性,基于化渣脱磷基础试验,对比了小颗粒石灰石与石灰在相同条件下的化渣脱磷效果,并从造渣脱磷机理上进行分析。研究表明:小颗粒石灰石在熔池内分解形成高活性石灰,可同时实现在熔池内部及界面的脱磷反应,脱磷效果与石灰相当,终点铁水脱磷率均可以达到85%以上;小颗粒石灰石比石灰的前期脱磷速率快,可以在更短的时间内将大部分磷元素脱除;小颗粒石灰石与石灰均可以实现均匀化渣,石灰石化渣渣层较高,泡沫渣更为明显,渣中元素分布均匀,磷元素主要富集在Ca_(3)(PO_(4))_(2)固溶体相中。