增量模型预报电弧炉终点碳含量及温度的研究

结合电弧炉炼钢未知因素众多的特点，运用统计型增量模型对电弧炉冶炼终点碳含量和温度预报进行研究，结果表明构造增量样本的参考炉应选本炉前一炉，并且不采用动态调节系数时预报效果较好。     

金、银湿法冶炼过程中氮氧化物气体处理工艺的可行性选择

主要介绍了黄金及其它贵金属湿法冶炼过程硝酸分银、王水分金工艺中产生的大量氮氧化物(NOx)气体对人体和周围环境的影响;同时,还介绍了国内外几种氮氧化物气体处理工艺,最终针对黄金及其它贵金属湿法冶炼过程中产生的大量氮氧化物(NOx)气体选择可行性处理工艺.     

转炉钢液终点氮含量研究

在120t转炉上进行不同底吹供气强度和切换供气时间的全程底吹供氮试验,以及底吹介质相同时不同终点碳的质量分数对钢液氮的质量分数影响的试验,试验表明,全程底吹供氮对钢液氮的质量分数有增加的趋势,但增加量不大,约为4×10^-6-10×10^-6;底吹介质相同但终点碳的质量分数不同,钢液终点氮的质量分数相差较多。由于氮气与氩气相比有较强的成本优势,在冶炼对氮的质量分数要求不苛刻的钢种时可以采用全程底吹供氮。但为了减少对钢液的增氮,在满足吹炼要求的前提下,应尽可能减小底吹供气强度。     

唐钢薄板坯连铸连轧钢液增氮的试验研究

通过试验研究了150 t顶底复吹转炉-150 t LF炉-薄板坯连铸连轧流程钢液w(N)的变化.研究发现:转炉出钢、吹氩操作、LF炉精炼和连铸过程均可能增氮,自转炉出钢至LF炉精炼开始过程和钢水从大包进入中间包过程增氮最为严重,平均增氮都接近20×10-6.对影响钢液增氮的一些因素进行了讨论,提出了相应的改进措施.     

控制SPHC钢硅含量的生产实践

针对低碳硅铝镇静钢SPHC硅含量超标的问题,从动力、热力学及实际生产方面进行了研究,结果表明控制硅含量的关键点在于:使用SiO2含量较低的原材料、保证进精炼站钢水较低硫含量、转炉控制下渣量3 kg/t以下、控制转炉出钢及LF处理各阶段合适的钢水AlS含量、精确控制吹氩流量、控制热态钢渣回收量8 kg/t以下等。实践中唐山钢铁集团有限责任公司第一钢轧厂SPHC硅合格率达到了100%,取得了很好的效果。     

Fuel enhancement by conversion of hotter waste CO2 in flue gas with coke

Considering the huge losses of high-temperature metallurgical waste heat and gases in steel works and the energy crisis on a worldwide scale, particularly the waste hotter gases in the flue of a converter that are emitted into air. A novel concept where coke is injected into the hotter gases for enhancement of fuel gas and reduction of CO₂ emissions into air is proposed. Numerical, experimental and industrial investigations are carried out in this work. The effects of injecting mass rate and inserted depth on the mixed state of coke in the flue were numerically evaluated and the effect of the surface structure of coke on the reactions of gas–solid phases was analysed using the t-plot method, and the transient gas products were described during coke injection. The energy change of the flue gas under various injecting schemes was discussed during the tests. The results show that an injecting scheme comprising an injecting pressure of 1.0?MPa, an inserted depth of 500?mm and an injecting mass rate of 18?kg?min^?1 seems to be better. The value of the specific surface area of coke was 8.36?m²?g^?1, while the coal was 20.59?m²?g^?1. With the inserted depth at 400 and 500?mm, the recovery time of the flue gas was 545 and 565?s and the total calorific value accounted for 48.47 and 51.53%, respectively. Without injection, the average contents of CO, O₂ and CO₂ were 48.1, 1.01 and 23.3, whereas after injection the average contents of CO, O₂ and CO₂ were 56, 0.5 and 10.1%, respectively. As a result, this process reduces CO₂ emissions and increases energy of the flue gas.     

Microscopic study on the interior and exterior reactions of coke with CO2 and H2O

The interior and exterior reactions of coke with H₂O and CO₂ were studied at 950–1250°C by self-made gas–solid reacting apparatus, including the particle diameter, apparent porosity, relative volume density distribution and pore structure of coke after reaction. It was obtained that the porcoke in the interior and exterior parts were all eroded after reacting with CO₂ or H₂O. However, compared with CO₂, the reaction of coke with H₂O occurred at the coke exterior more strongly, but in the coke interior occurred more weakly, indicating the reaction area of coke with H₂O was much closer to the coke exterior. Therefore, injecting hydrogen fuel into blast furnace can increase the coke particle size, so as to make coke playing a better role as skeleton in blast furnace. In addition, increasing the temperature can reduce the amount of solution loss in the coke interior, in particular for the reaction with H₂O.     

重审钢铁企业煤气系统不平衡问题

针对钢铁企业煤气系统不平衡问题,指出主要是自备电厂机组设计不合理导致煤气系统结构性静态不平衡。采用概率统计与数值分析的方法,以钢铁企业煤气富余量的统计特性为基础,重新审视煤气系统不平衡问题。以年产280万t粗钢的钢铁联合企业为例对自备电厂机组进行设计,以小时煤气富余量最大值为基准设计7种发电方案,并结合各设计方案的经济效益进行财务评价,得到以90%小时煤气富余量最大值设计本钢铁企业自备电厂机组大小最为合理。以避免生产状况变化较大时煤气的大量放散,使富余煤气得到了合理、安全高效利用,有效缓解煤气系统不平衡的问题,提高了能源利用效率,降低了生产费用。同时针对各方案建立了此钢铁企业自备电厂煤气系统环境成本模型,虽然增加了企业的总运行成本,但对环境保护和经济社会可持续协调发展有着十分重要的意义。     

Effect of CaF2 and SiO2 modification on phosphorus utilisation in P-bearing slag

Abstract

In order to recycle phosphorus in P-bearing converter slag for slag phosphate fertiliser, the effect of CaF₂ and SiO₂ modification on P-bearing steelmaking slag on phosphorus-bearing phases, P₂O₅ solubility and magnetic separation behaviour has been researched. The results show that the phosphorus-rich phase is mainly n2CaO·SiO₂–3CaO·P₂O₅ (nC₂S–C₃P for short) and exists along with fluorapatite phase [Ca₅(PO₄)₃F] after the addition of CaF₂. The fluorapatite cannot be dissolved in 2% citric acid solution, which decreases the P₂O₅ solubility in slag. Although adding CaF₂ can increase the P₂O₅ content of phosphorus-rich phase, it can improve its metallisation and magnetisation of RO phase, increase the amount of recovered magnetic substances, and separate incompletely phosphorus and iron, therefore it is adverse to the phosphorus recovery from P-bearing slag by magnetic separation. P₂O₅ content of phosphorus-rich phase is more than 31% and P₂O₅ solubility of slag is increased to 96% in fluorine-free modified slag, which can meet the requirement of P₂O₅ content and P₂O₅ solubility of the phosphate fertiliser. Meanwhile, 87.1% of the phosphorus in the fluorine-free modified slag is contained in non-magnetic substance, and most of the phosphorus was recycled.     

Gas release from the ZrO<Subscript>2</Subscript>-Y<Subscript>2</Subscript>O<Subscript>3</Subscript> ceramics used in the seeded growth of diamond single crystals

Gas release from the ZrO₂-Y₂O₃ ceramics used for the seeded growth of diamond single crystals in a temperature range from 100 to 700°C and a pressure of 10^?4 Pa is investigated. It is experimentally found that the air content in the pores of ceramic elements of the container is 0.086 sccm³/g. The coefficient of the gas release and diffusivity are determined; this allows one to determine the degassing time for which the gas fraction from the sample attains a definite value from the starting amount. It is revealed that vacuum annealing at a temperature no lower than 700°C and P = 10^?4 Pa provides a decrease in the content of the adsorbed gas on the parts of the reaction cell by an order of magnitude.     

Effect of the firing temperature and the added MgO on the reduction swelling index of the pellet with low SiO2 content

The use of pellet with low SiO₂ content in blast furnace (BF) will reduce the slag amount as well as fuel rate and increase the productivity. In this paper, the effect of the firing temperature and the added MgO on the reduction swelling index (RSI) and the compressive strength of the reduced pellet with low SiO₂ content was investigated, and the microstructure of the fired and reduced pellets was analysed by means of the electron microscopy. It was found that the decrease of SiO₂ content will raise the RSI and reduce the compressive strength of reduced pellet. When the SiO₂ content of pellet is 4.8%, the RSI is 16.5% and compressive strength of reduced pellet is 423 N/P. When the SiO₂ content is 2.8 and 1.8% fired at 1280°C, the RSI of the reduced pellet will increase to 34.5 and 55.8% and the compressive strength is reduced to less than 200 and 80 N/P. However, if some MgO was added, the RSI and the compressive strength of the reduced pellet could be improved significantly. When pellet’s MgO content was over 1.7% and SiO₂ content was 2.8% or MgO content was 2.5% and SiO₂ content was 1.8% fired at 1280°C, the RSI of the two pellets could drop to less than 20% and the compressive strength could increase to more than 300 N/P. Then, the technical index of pellet will meet the requirement of the charging in large BF. The added MgO pellet with low SiO₂ content have been used in 5500?m³ BF in Shougang Jingtang Corporation and delivered sustainable improvement of cost reduction.     

鞍钢干熄焦预存段放散烟气处理技术研究与应用

研究了一种焦炉干熄焦预存段放散烟气处理技术,通过将经过防爆袋式除尘器过滤后的干熄焦预存段放散烟气汇入焦炉烟道气脱硫脱硝系统进行处理,实现了干熄焦预存段放散烟气除尘脱硫净化目的,同时采用安全联锁自动控制技术,以保证干熄焦炉系统的稳定运行和安全生产。该技术应用后,干熄焦装置烟气SO2排放≤30mg/Nm^3、颗粒物排放≤15mg/Nm^3,完全满足《炼焦化学工业污染物排放标准》GB16171-2012要求。     

Study on the preparation and electrochemical performance of rare earth doped nano-Ni（OH）2

Multiphase nano-Ni(OH)2 doped with Y or La was prepared by supersonic co-precipitation method. The crystal morphology, structure and particle size were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and particle size distribution (PSD). The electrochemical performance of samples was investigated by electrochemical workstation and battery tested system. The results indicated that micro-morphology and grain size were changed with the changing of supersonic power, pH values and doping elements. The morphology of Y doped sample was from the flake-like to the needle-like with the increase of supersonic power; Particles were from quasi-spherical particles into needle-like with the increase of pH values; As the supersonic power increased, the proportion of α-Ni(OH)2 increased initially and then decreased. pH value was very important to the formation of crystalline phase. Lower pH value was beneficial to the formation of α-Ni(OH)2. However, the pH values had a slight effect on the reaction reversibility. Complex electrodes were prepared by mixing 8 wt.% nickel hydroxides with commercial micro-size spherical nickel. The discharge capacity of electrodes increased initially and then decreased with the increase of supersonic power. When the supersonic power was 60 W and the pH value was 9, the sample had the largest dis-charge capacity (358 mAh/g) at 0.5 C rate, which was 122.7 and 76 mAh/g higher than the spherical nickel electrode and La doped sample electrode, respectively.