低温低碱度脱磷渣中磷的富集行为

At low basicity and low temperature, the dephosphorization behavior and phosphorus distribution ratio (L_P) between slag and molten steel in the double slag and remaining slag process were studied with a 180 t basic oxygen furnace industrial experiment. The dephosphorization slags with different basicities were quantitatively analyzed. At the lower basicity range of 0.9–2.59, both L_P and dephosphorization ratio were increased as the basicity of dephosphorization slag increased. Dephosphorization slag consisted of dark gray P-rich, light gray liquid slag, and white Fe-rich phases. With increasing basicity, not only did the morphologies of different phases in the dephosphorization slag change greatly, but the area fractions and P₂O₅ content of the P-rich phase also increased. The transfer route of P during dephosphorization can be deduced as hot metal → liquid slag phase + Fe-rich phase → P-rich phase.     

合成精炼渣对钢水脱磷作用的研究

采用CaO-Al2O3-MgO-BaO-CaF2渣系,在实验室内依据冶金热力学和动力学理论进行热模拟实验,对不同量的原料配比进行了精炼渣的脱磷实验,系统的分析了初始磷含量、碱度、光学碱度、BaO、CaF2等因素对脱磷能力和脱磷反应速率的影响。研究表明,BaO部分取代CaO时,脱磷率高,碱度小于30,光学碱度小于0.9,CaF2在16%-18%,脱磷率高。     

全电子系炉渣热力学在BaO基脱磷渣系中的应用

论述应用电子系炉渣热力学，推导出了磷在渣钢分配比的表示式ＬＰ＝ＫＰｆ［Ｐ］ｐｏ２γ（Ｐ）／ψ（Ｐ），并据此讨论了温度Ｔ，脱磷反应平衡常数ＫＰ，氧分压ｐｏ２，磷在熔渣中的原子活度系数ψ（Ｐ）和磷在钢中的原子活度系数ｆ［Ｐ］对脱磷的影响，得出了实验基本一致的结果。     

高磷铁水预处理环保脱磷渣系的相图计算和实验研究

采用FactsageTM软件对以B2O3、K2O、MnO2、TiO2代替CaF2助熔的4种高磷铁水预处理脱磷渣系在1 623 K时的相图进行计算,发现相图中的多数区域都有液态渣出现.根据计算相图制定脱磷实验的配渣方案,实验过程中观察到的化渣情况与计算相图提供的信息基本一致.     

基于多功能转炉炼钢法的连续循环冶炼过程

为了研究脱碳渣在脱磷期的重新利用,基于多功能转炉炼钢法进行连续循环冶炼实验.实验发现：脱磷阶段渣中较低的FeO含量、吹炼5 min左右,[ C]≥2.8%的条件下,可实现转炉熔池内铁液[ P]≤0.025%的脱磷效果,并对低( FeO)含量炉渣的脱磷可行性进行热力学计算;随着循环的进行,石灰加入量逐渐降低,由65 kg·t-1降低至31 kg·t-1,转炉冶炼终点钢水[ P]量由0.018%降低至0.005%,2~4炉后达到平衡状态;在循环过程中,脱磷阶段结束倒出炉渣60~80 kg·t-1,整个循环结束一次性倒出剩余全部炉渣120~130 kg·t-1,平均渣量为83 kg·t-1左右,较普通工艺的120 kg·t-1渣量有大幅度减少.     

高磷铁水脱磷渣枸溶性

参照实际转炉脱磷炉渣,配制了不同F、P2O5、FeO和MgO含量及碱度的渣样,用化学分析方法测试了不同组分对渣中磷的枸溶率的影响规律.结果表明:当脱磷渣中含有F时,P主要与F形成氟磷灰石,使得磷的枸溶率随渣中F含量的升高而急剧降低,当不含氟时枸溶率可达92.5%,当氟质量分数达到0.5%时枸溶率已降低到50%以下;随碱度增加,由于渣中Ca2+含量增加,破坏了硅氧网络结构,使得枸溶率有所上升;渣中MgO含量升高,由于Mg2+在熔融冷却过程中会抑制β--Ca3(PO4)2晶体的析出,而β--Ca3(PO4)2中磷不易为质量分数为2%的柠檬酸液溶出,而使枸溶率有所升高;随渣中P2O5含量升高,由于P5+与O2-形成络离子,P5+位于O2-密集形成的间隙中,不易溶出,使得枸溶率有所下降;渣中FeOn升高,枸溶率随之降低.     

组合脱磷剂对高磷铁矿还原焙烧-磁选的影响

针对高磷铁矿还原焙烧降磷过程中脱磷剂成本高、用量大等难题，为更好地开发利用高磷铁矿，采用还原焙烧-磁选工艺，研究了组合脱磷剂对高磷铁矿提铁降磷的影响.通过X射线衍射(XRD)和扫描电子显微镜-能谱仪(SEM-EDS)揭示提铁降磷机理.结果表明:加入13%碳酸钙和2%碳酸钠作为组合脱磷剂能代替传统脱磷剂，并获得了良好的脱磷效果.当原矿铁品位55.58%，含磷0.57%时，在推荐的试验条件下，可获得铁品位93.25%，铁回收率90.75%、磷质量分数0.09%以及磷的去除率高达91.46%的粉状还原铁.加入的组合脱磷剂不仅促使铁氧化物中的磷组元向磷酸钙发生转变，使金属铁颗粒与磷酸钙界限明显，而且还能防止难以还原的铝尖晶石和铁橄榄石的生成，最终实现了磷的深度脱除和铁的有效回收.     

石灰石替代部分石灰进行脱磷的实验分析

为了研究石灰石替代石灰的比例(即石灰石替代比)及加入方式对脱磷效果的影响,通过调整石灰石加入量在真空感应炉内进行热态实验。实验结果表明:采用石灰石替代石灰进行造渣炼钢是切实可行的,而且石灰石加入方式对脱磷效果有显著影响;石灰石替代比为40%时脱磷效果最好,终点磷含量由初始的0.12%降低至0.012%,相比石灰石替代比为0%的原方案脱磷率提高24.17%;石灰石替代比为80%时出现严重的炉渣结壳现象,冶炼无法正常进行。石灰石脱磷较适宜方案有2种:一是强调降低生产成本,60%石灰石替代比进行冶炼;二是强调提高产品质量,40%石灰石替代比进行冶炼。     

转炉铁水预处理脱磷的基础理论分析

通过对转炉铁水预处理脱磷过程中选择性氧化的热力学和动力学分析,并结合首钢京唐公司300 t脱磷转炉的生产数据,研究熔池中铁、硅、锰、碳、磷的氧化过程,讨论影响磷在渣铁间分配比以及脱磷速率的主要因素.研究表明,将转炉铁水预处理温度控制在较低范围内（1 300～1 350 ℃）,选择具有合适碱度（1.7～2.5）和成渣快的造渣工艺,并结合高的底吹搅拌强度（≥0.2 Nm3/(t·min)）,这是实现脱磷保碳、提高脱磷速率、加快生产节奏的有效途径.     

转炉渣中磷的微观结构行为

为了设计合理的转炉渣成分以达到满意的脱磷效果，根据转炉炼钢过程熔渣成分的变化范围，采用拉曼光谱测定了CaO-SiO₂-Fe_○xO-P₂O₅系熔渣的熔体结构，并解析了磷在熔渣中的存在形式及转变行为.结果表明，熔渣中磷主要以桥氧数为0，1，2的磷氧四面体结构单元存在，并可进入硅氧四面体和铁氧四面体形成Si—O—P和Fe—O—P键.随着渣中CaO和FeO总量的增加，熔渣中聚合程度较低的Q⁰(P)，Q¹(P)和Q⁰(Si)，Q¹(Si)摩尔分数升高，而聚合程度较高的Q²(P)和Q²(Si)，Q³(Si)摩尔分数降低.另外，Fe—O—P和Si—O—P键的含量也逐渐降低，当碱度为2.83时，Si—O—P和Fe—O—P键消失.     

CaC_2-CaF_2渣系对铁水脱砷的研究

采用CaC_2-CaF_2渣系作为脱砷剂,在实验室范围内进行了铁水还原脱砷的研究。 实验是在钼丝炉内,Ar气氛下,石墨坩埚中进行的。研究了温度、渣成份、渣量、初砷含量和铁水含si量等因素对脱神效率的影响。 通过热力学分析说明了在钢铁溶液中,只能还原脱砷而不能氧化脱砷;用CaO-CaF_2、CaC_2-CaF_2渣系对铁水同时脱硫脱磷脱砷是不可能的。     

某高磷鲕状赤铁矿磷赋存状态及还原焙烧脱磷研究

采用浸出、电渗析等试验方法研究了尼日利亚高磷鲕状赤铁矿中磷的赋存状态并采用XRD和SEM分析添加脱磷剂Na2CO3直接还原焙烧产物的特性.结果表明,含磷矿物主要是呈微细粒包裹体嵌布在铁矿物鲕粒的裂隙或孔洞中的纤磷钙铝石(CaAl3(OH)6(HPO4)(PO4))、蓝磷铝铁矿(FeAl2(PO4)2OH·6H2O)以及均匀分散在铁矿物中的磷.通过添加脱磷剂Na2CO3的还原焙烧磁选可实现高效铁磷分离.磷通过两种方式去除:一部分含磷矿物与金属铁分离,存在于脉石矿物中,通过磨矿磁选可以有效去除,一部分含磷矿物与Na2CO3反应生成溶于水的磷矿物,最终使得还原铁产品中的磷含量降低.     

BaO-CaO基精炼渣对含铬铁水的氧化脱磷

在氩气保护气氛的MoSi2炉内,进行了BaO-CaO基精炼渣对不同初始碳含量的含铬铁水氧化脱磷实验研究.实验结果发现,含铬铁水的初始碳质量分数在3%-4%时,脱磷效果最好,在1 500℃时,脱磷率可达60%以上;氧化脱磷温度对脱磷率影响显著,随着温度的升高,脱磷率显著下降,脱磷温度宜控制在1 500-1 550℃;含铬铁水几乎没有铬损,初始碳含量较高的炉次出现了增铬现象.     

Activity coefficients of NiO and CoO in CaO-Al2O3-SiO2 slag and their application to the recycling of Ni-Co-Fe-based end-of-life superalloys via remelting

To design optimal pyrometallurgical processes for nickel and cobalt recycling, and more particularly for the end-of-life process of Ni-Co-Fe-based end-of-life (EoL) superalloys, knowledge of their activity coefficients in slags is essential. In this study, the activity coefficients of NiO and CoO in CaO-Al₂O₃-SiO₂ slag, a candidate slag used for the EoL superalloy remelting process, were measured using gas/slag/metal equilibrium experiments. These activity coefficients were then used to consider the recycling efficiency of nickel and cobalt by remelting EoL superalloys using CaO-Al₂O₃-SiO₂ slag. The activity coefficients of NiO and CoO in CaO-Al₂O₃-SiO₂ slag both show a positive deviation from Raoult's law, with values that vary from 1 to 5 depending on the change in basicity. The activity coefficients of NiO and CoO peak in the slag with a composition near B=(%CaO)/(%SiO₂)=1, where B is the basicity. We observed that controlling the slag composition at approximately B=1 effectively reduces the cobalt and nickel oxidation losses and promotes the oxidation removal of iron during the remelting process of EoL superalloys.     

复吹转炉多功能法脱磷工艺

在不新增设备的前提下,通过优化转炉冶炼工艺,使用复吹转炉多功能法进行铁水脱磷,提高转炉脱磷率.根据现有转炉设备条件,通过热力学计算确定转炉前期脱磷温度范围,并在现场实验中掌握好倒渣时机、渣碱度、加料量和出钢温度,确定最佳脱磷工艺.分析实验结果,与常规冶炼相比,该脱磷工艺用原料量少,脱磷率稳定,且高达90%以上,在提高钢水质量的同时也降低了生产成本.     

Activity coefficients of NiO and CoO in CaO-Al2O3-SiO2 slag and their application to the recycling of Ni-Co-Fe-based end-of-life superalloys via remelting

To design optimal pyrometallurgical processes for nickel and cobalt recycling, and more particularly for the end-of-life process of Ni–Co–Fe-based end-of-life (EoL) superalloys, knowledge of their activity coefficients in slags is essential. In this study, the activity coeffi-cients of NiO and CoO in CaO–Al2O3–SiO2 slag, a candidate slag used for the EoL superalloy remelting process, were measured using gas/slag/metal equilibrium experiments. These activity coefficients were then used to consider the recycling efficiency of nickel and cobalt by remelting EoL superalloys using CaO–Al2O3–SiO2 slag. The activity coefficients of NiO and CoO in CaO–Al2O3–SiO2 slag both show a positive deviation from Raoult’s law, with values that vary from 1 to 5 depending on the change in basicity. The activity coefficients of NiO and CoO peak in the slag with a composition near B = (%CaO)/(%SiO2) = 1, whereB is the basicity. We observed that controlling the slag composition at approximatelyB = 1 effectively reduces the cobalt and nickel oxidation losses and promotes the oxidation removal of iron during the remelting process of EoL superalloys.     

Effect of slag composition on the cleanliness of 28MnCr5 gear steel in the refining processes

The equilibrium reaction between CaO—Al₂O₃—SiO₂—MgO slag and 28MnCr5 molten steel was calculated to obtain the suitable slag composition which is effective for decreasing the oxygen content in molten steel. The dissolved oxygen content [O] in molten steel under different top slag conditions was calculated using a thermodynamic model and was measured using an electromotive force method in slag–steel equilibrium experiments at 1873 K. The relations among [O], the total oxygen content (T.O), and the composition of the slag were investigated. The experimental results show that both [O] and T.O decrease with decreasing SiO₂ content of the slag and exhibit different trends with the changes in the CaO/Al₂O₃ mass ratio of the slag. Increasing the CaO/Al₂O₃ mass ratio results in a decrease in [O] and an increase in T.O. To ensure that T.O ≤ 20 ppm and [O] ≤ 10 ppm, the SiO₂ content should be controlled to <5wt%, and the CaO/Al₂O₃ mass ratio should be in the range from 1.2 to 1.6.     

CaO-SiO2-FetO-P2O5渣中磷的富集行为

通过考察不同温度下CaO-SiO2-FetO-P2O5熔渣中磷在2CaO·SiO2颗粒内部和表面以及熔渣本体中的浓度分布规律,对CaO-SiO2-FetO-P2O5熔渣中磷的富集行为进行了研究.结果表明:熔渣中存在的2CaO·SiO2固体颗粒为渣中磷富集提供了场所,磷向2CaO·SiO2颗粒富集并形成2CaO·SiO2...     

碳酸钠在高磷鲕状赤铁矿直接还原中的作用

为了研究碳酸钠对尼日利亚某高磷鲕状赤铁矿直接还原焙烧-磁选脱磷效果的影响,采用X射线衍射(XRD)和扫描电镜(SEM)研究了添加碳酸钠后直接还原焙烧的产物.结果表明,还原焙烧过程中添加碳酸钠后可以实现脱磷:碳酸钠的加入抑制了铁橄榄石的生成,阻断了磷进入金属铁的过程;使得鲕粒结构破坏,促进金属铁颗粒的聚集长大,有利于金属铁颗粒与脉石的解离;原矿中含磷矿物在焙烧过程中与碳酸钠反应生成可溶性的Na3PO4,在磨矿磁选过程中溶于水,使直接还原铁中磷的含量降低.     

转炉泡沫渣气泡分布特点及形成过程

在转炉留渣-双渣工艺脱磷阶段结束倒渣时，分别使用样勺获取倒渣开始时上部泡沫渣，倒渣结束时下部泡沫渣以及倒渣结束后炉内剩余底部泡沫渣，使用宏观及微观的方法分别分析泡沫渣各部位气泡分布特点。结果表明：气泡平均当量直径，上部>下部>底部；孔隙率，上部>下部>底部。转炉泡沫渣的形成过程为：随着大量CO/CO2气泡进入渣中，气泡之间不断碰撞、合并，上部气泡被下部气泡抬挤且由于气泡本身的浮力作用，气泡不断上升，气泡在上升时由于重力作用，气泡之间渣相在重力作用下析液，气泡的拓扑结构不断发生变化，同时气泡之间不断碰撞、合并，最后形成上部气泡直径大且孔隙率高，下部气泡直径小且孔隙率低的泡沫渣。