低砷铁矿石烧结脱砷试验研究

针对低砷铁矿石使用量低的问题,通过在烧结杯中对含毒砂的低砷铁矿石进行烧结脱砷试验,研究了料层厚度、料层位置、配煤比、抽风负压、碱度等因素对低砷铁矿石烧结脱砷率的影响。结果表明,烧结工序具有较好的脱砷效果,脱砷率可达60%以上,料层厚度变化对烧结脱砷过程影响不大,料层位置、配煤比及碱度均对脱砷率有一定影响,抽风负压影响较大。在弱氧化性气氛条件下,含毒砂的低砷铁矿石合适的脱砷工艺为:配煤比5.0%~6.0%、抽风负压14 kPa、高碱度。     

含砷铁矿石烧结及除尘灰焙烧脱砷热力学

 为了研究铁矿石烧结及除尘灰焙烧脱砷问题,运用FactSage软件研究了不同氧分压、温度及碱度对含砷铁矿石烧结脱砷率、砷平衡组成、脱砷最终形态的影响,并对除尘灰焙烧脱砷流程进行热力学研究。结合烧结杯进行烧结试验,并在多气氛下利用焙烧除尘灰试验进行验证,运用XRD、SEM及EDS对矿相进行分析。结果表明,脱砷产物及脱砷率与温度、氧分压及碱度密切相关。在烧结过程中,残留在烧结矿中的砷,主要是固态砷酸盐,其他砷会以As4O6（g）等气态物质脱除。除尘灰中砷以固态As2O3（s）和As2O5（s）存在。在空气或厌氧气氛下焙烧除尘灰,会使砷转变为砷酸盐。但采用配比煤粉及厌氧条件下,在600 ℃以上焙烧除尘灰,可使砷以气态As4（g）挥发,在400 ℃以下析出单质砷。     

含砷铁矿石烧结脱砷的试验研究

采用化学分析、XRD、高倍显微镜、EDS、XPS及原子吸收光谱分析等测试技术确定华南含砷铁矿石的理化性质,研究不同因素对华南含砷铁矿石烧结脱砷的影响并确定适宜的烧结脱砷工艺参数。结果表明:华南含砷铁矿石主要以磁铁矿和脉石为主,其中砷以FeAsS及少量As2S3形式存在,其质量分数为0.282%。华南含砷铁矿石烧结过程砷化物主要发生FeAsS的氧化和热分解反应。在弱氧化气氛条件下,华南含砷铁矿石的脱砷率随反应温度的升高、恒温时间的延长、焦粉配入量的提高而增加。反应温度1050~1100℃、恒温时间8~15 min、焦粉配入量6%为适宜的脱砷工艺参数。     

配合矿石中脉石成分对含砷褐铁矿脱砷的影响 通过预处理进行含砷褐铁矿脱砷的基础研究之三

一、绪言北海道开采的褐铁矿都有不同含量的砷。由于在炼铁以后的精炼过程中不可能脱砷,所以在装入高炉之前一定要用预处理进行铁矿石脱砷。有关这方面的研究,笔者已经发表了两篇文章。第一篇是“气氛对褐铁矿脱砷的影响”,第二篇是“褐铁矿的脱砷机理及促进脱砷的物质”。因此本文将论述“配合矿石中脉石成分对褐铁矿脱砷的影响”。在矿石预处理方法之一的烧结过程中,不是单纯地烧结含砷褐铁矿,通常是和各种国外矿石配合烧结。可是配合的国外矿石多种多样,它们所含有的脉石也不相同,SiO_2、Al_2O_3、CaO、MgO等含量也有变化,这样的化学成分对脱砷将带来什么样的影响,多半还不清楚。因此,本文把预处理过程中存在于铁矿石里的脉石成分中常见的化合物分成酸性氧化物     

不同脱砷剂钢液脱砷研究

为了充分利用我国含砷铁矿资源,采用CaO+CaF₂、CaC₂+CaF和Si-Ca-Ba合金+CaF₂对钢液进行脱砷研究,获得较高的脱砷率,其中Si-Ca-Ba合金+CaF₂脱砷效果最明显,其脱砷率最高可达67.7%.在相同实验操作条件下,通过实验室研究,分析比较了温度、传质系数和S含量对不同脱砷剂脱砷效果的影响.      

不同钙合金对钢液脱砷作用的实验研究

为了充分利用我国含砷铁矿资源,采用精炼渣+不同Ca合金对钢液进行脱砷研究,获得较高的脱砷率,其中Si-CaBa合金综合脱砷效果最佳.在相同操作条件下,通过改变实验条件,对钢液中砷含量随时间变化规律以及对脱砷效果的影响进行研究,并对高砷含量下不同Ca合金加入钢液后Ca的有效利用率进行详细分析.      

影响铁水用CaO-CaF2渣系脱砷的因素

为降低Y钢厂生产成本,充分利用周边含砷铁矿资源,采用CaO-CaF2渣系作为脱砷剂进行铁水脱砷实验研究,获得了较高的脱砷率.渣系组成为65 ％CaO-35 ％CaF2的炉渣脱砷效果最明显,其脱砷率可达62.68％.通过实验室研究,分析了渣量、渣中w(CaO)、温度、反应时间、铝粉加入量、铁水中w(C)、w(Si)、w(S)等因素对脱砷反应的影响,确定了最佳脱砷条件.同时,通过热力学计算,得出了脱砷率与铝粉加入量之间的关系式.     

诱导法脱铜、砷、锑、铋的生产技术研究

本文对白银公司一年来诱导法脱砷、锑、铋的生产进行了简要的总结,对电积过程机理进行了研究,同时通过生产实践中技术数据的分析,提出诱导法脱铜、砷、锑、铋的最佳工艺技术条件,并对过程中重要经济技术指标及砷化氢气体的有效抑制作了进一步的探讨。     

铁水还原脱砷的研究

以含砷铁液为研究对象,采用还原脱砷的思路,在实验室条件下系统研究了不同脱砷剂对铁(钢)水脱砷效果的影响。结果发现,低温有利于脱砷反应的进行;不同的脱砷剂对含砷铁水有不同的脱砷效果,但是选用的自制添加剂脱砷效果最好,脱砷率最高可达到58.6%,而其它脱砷剂最高不超过25%。研究还发现,铁水中的磷含对脱砷率有较大的影响,随着铁水中磷含量的降低,脱砷率明显提高。     

气氛对含砷褐铁矿脱砷的影响 通过预处理进行含砷褐铁矿脱砷的基础研究之一

从日本的现状来看,有效地利用国内贫矿是很重要的。最近,随着技术的显著进步,对钢铁产品的质量要求更加严格,但与此相反,国内矿石质量却日益下降,特别成问题的是国内矿石的夹杂物含量。在北海道开采的褐铁矿都有不同含量的砷。砷和钢铁中的其他有害元素硫、磷等不同,它在炼铁工序以后的精炼过程中不能除去,而必须靠炼铁之前的焙烧、烧结等工序加以去除。从前,也曾进行过由预处理脱砷的各种研究,然而对褐铁矿脱砷的基本条件,即气氛对脱砷的影响,脱砷机理,含砷矿石以外的配合矿石中脉石成分对脱砷的影响以及促进脱砷的     

重庆高校推进产学研合作的案例分析

以重庆大学、重庆邮电大学和重庆理工大学为例,剖析重庆高校推进产学研合作的基本模式,已经取得的突出成绩,分析总结其基本经验.从完善政策法规体系、强化经济调控、建立组织机构、加强中介建设及开展国际产学研合作等方面,提出了深入推进重庆高校产学研合作的对策建议.     

Benzimidazole resistance in cyathostomes in horses in the Ukraine

The efficacy of treatment with cambendazole was tested in 1-year-old horses on a farm in Dubrovka, Ukraine. Thirty-five horses were treated. Their egg output was compared on the day of treatment and 14 days later with that of 33 untreated horses. Before treatment the mean number of eggs g-1 faeces was 614 in the controls and 766 in horses that had been treated. After 14 days the mean egg output in the controls was 580 and in the treated horses 369. This means a reduction of 54.5%. Only cyathostome larvae could be cultured from faeces collected after treatment. It can be concluded that benzimidazole resistance in cyathostomes is present in the Ukraine.     

Apoptosis in experimental myocardial infarction in situ and in the perfused heart in vitro

We report the appearance of apoptotic cells in experimental myocardial infarction (rabbit heart) in in situ and in vitro preparations. Apoptosis was recognized by intravital staining with Hoechst 33342 (Ho342), by nick-end labeling (TUNEL) and by DNA laddering. A steady rise in the relative number of apoptotic cardiomyocytes (apoptotic index) was noted in in situ preparations. Apoptosis was first noted 6 h after the onset of ischemia with its highest value occurring after 72 h. Apoptotic nuclei were absent in remote areas of the left and right ventricles. Apoptotic nuclei within the infarcted area showed diminished intensity of Ho342 fluorescence. Three days after ischemia, a border zone adjacent to the infarcted area consisting of apoptotic macrophages was recognized. A novel finding was the appearance of apoptotic cardiomyocytes in the isolated perfused ischemic heart. Occurring as early as 50 min after the onset of ischemia, a high apoptotic index was present adjacent to the ligature placed around the coronary artery. This observation provides the opportunity to selectively examine factors leading to apoptosis in the ischemic heart under controlled experimental conditions.     

Fractures in childhood in Khartoum

A prospective study of fractures in 231 children received at Khartoum North Teaching Hospital(KNTH) was carried out for a period of six months. The incidence of child fracture rated as one per day, then it increased from the age of 5 years onwards in boys and between 6 and 8 years in girls. Most injuries were sustained during the day time, especially between late afternoon and sunset. 82% of injured children presented to a medical facility, while 18% were taken to native healers first. Non-road traffic accidents accounted for 84% of the fractures mainly due to sports, domestic injuries and falls; whereas road traffic accidents were 16% and occurred mainly in pedestrians. Forty three percent of the fractures needed only first aid and splintage while 42% needed closed reduction. Thirty one percent of all patients were treated as inpatients. The long bones were affected in 91% of all fractures, the commonest site being the distal end of the forearm (26%), followed by supracondylar fracture of the humerus (15.6%). In the upper limb, left-sided fractures predominated. The epiphyseal injuries were 3.5% of all fractures, mainly at the distal radial epiphysis. Boys were commonly affected between 13-15 years of age. Open fractures constituted 9.8% of the series and were mainly due to traffic accidents in town dwellers, the most vulnerable bones were those of the leg and foot. Pathological fractures accounted for 2.2% and were due to bone cysts and osteogenesis imperfecta. The problem of child safety and the preventive measures need to be more stressed.     

Heatstroke in runners in Oklahoma

It is a common opinion that general surgery is the first step for whoever approaches a surgical discipline, and that whoever practices training in general surgery should learn the rudiments of each surgical branch. The role of microsurgery in the training of the general surgeon has not been well-established. Clinical applications of microsurgery in general surgery are few and are rarely required, and have been connected strictly to restricted indications. However, we think that microsurgery could be very useful to the general surgeon because it allows the execution of experimental research on rats, the only possibility permitted by law. In these studies the microsurgeon can perform many times and in a short time the same surgical operation, thus improving his skill, and easily getting familiarity with surgical instruments and sutures.