泡沫铝材料的研究与应用

泡沫金属具有实体金属不具备的热、声、轻质、能量吸收等优异性能,成为一种新型结构功能材料.被誉为"金属明星"的多孔泡沫铝材料是目前研究最为热门、最具应用潜力的泡沫金属,具有密度小、耐高温、抗腐蚀、不易燃、耐候性好、导热率低、电磁屏蔽强、吸能降噪等优异性能,被广泛应用在汽车工业、航空航天、建筑工业等工程领域.本文综述了泡沫...     

Processing of nickel- and cobalt-containing leach liquors obtained from different raw materials

Acidic as well as ammoniacal leach liquors obtained from three different raw materials, namely, lateritic nickel ores, copper converter slag and Indian Ocean manganese nodules, were treated for removal of impurities and separation of copper, nickel and cobalt. Precipitation and solvent extraction techniques were used for these purposes. Iron and silica impurities from acidic solutions were removed by lime precipitation. In ammoniacal medium, iron was coprecipitated with manganese. Manganese was removed as manganese dioxide by oxidative precipitation from both media; this removal also results in some loss of cobalt due to its adsorption on the manganese dioxide matrix. From sulphate solutions, copper was extracted using LIX 64N^®1 followed by nickel-cobalt coextraction using di-2-ethylhexylphosphoric acid (D2EHPA). From the loaded solvent, nickel and cobalt were separated by the crowding technique. From ammoniacal solution, both copper and nickel were coextracted with LIX 64N and separated by selective stripping from the loaded organic phase. Cobalt was recovered either by sulphide precipitation or by adsorption on lignite followed by desorption with sulphuric acid/spent electrolyte.     

Mechanical properties of materials obtained from an ultrafine aluminum nitride powder

Conclusions A study was made of the mechanical properties of materials produced from an ultrafine aluminum nitride powder. It is shown that use of such a fine powder enables virtually nonporous specimens to be produced having high strength characteristics: _c=1600 MPa, _tr= 320 MPa, microhardness of 16,800 MPa, microstrength of 3100 MPa, and microbrittleness of 1.9. On the basis of the results obtained it is possible to recommend aluminum nitride sintered from an ultrafine powder as a good-quality constructional ceramic material.Translated from Poroshkovaya Metallurgiya, No. 12(240), pp. 65–69, December, 1982.     

Gold recovery from non-metallic secondary raw materials by leaching with thiourea and adsorption on ion exchangers

Elemental gold on non-metallic secondary raw materials is easy to dissolve by leaching with sulphuric acid solutions of thiourea in the presence of an oxidant such as iron(III) sulphate or hydrogen peroxide. Leaching time is highly dependent upon oxidant concentration and the thickness of the gold coating. The gold goes into solution as the Au[SC(NH₂)₂]_2⁺ complex and can be removed almost completely using cationites, the gold residues being not greater than 6 μM. The gold-free leaching solution may be reused for leaching; the completely-loaded cationite resin (with a gold content of about 30–60 g/l) is burnt to recover the gold.A study of the adsorption of Au and Fe by cationites indicates that the adsorption of gold takes place purely by means of an ion-exchange mechanism, the bond of the gold complex being considerably stronger than that of the iron compounds.     

The mechanical properties of materials from iron powder obtained by the reduction of martite ore

Conclusions The article presents the results of an investigation of the mechanical properties of samples of iron powder obtained by reducing martite ore by converted natural gas.The use of this raw material for producing iron powder for the needs of the powder metallurgy industry permits a considerable extension of the raw material reserves.As a result of the investigations the authors determined the characteristics of strength, plasticity and fatigue strength of material of varying porosity.The regularities of deformation of such materials and the strength characteristics of the duration of load application were studied.The results show that the strength and plasticity of metal powder materials of similar composition made of other kinds of iron powders.     

Influence of melting conditions of aluminum alloys on the properties and quality of castings obtained by lost foam casting

The development of modern foundry production is characterized by a constant increase in requirements for the quality of fabricated casting and rational use of material resources, which determines the search for new technical and process solutions, making it possible to acquire the required properties of cast wares along with resource saving. Herewith, the question of revelation and investigation into the regularities of the influence of thermal-temporal parameters of smelting and pouring of aluminum alloys into the casting mold during the lost foam casting on tightness and mechanical and qualitative characteristics of thin-wall castings remain poorly known and complex for implementation, especially allowing for the performance of resourcesaving measures. In this publication, the influence of process parameters of smelting on the strength, tightness, and content of nonmetallic inclusions in castings of the gas-analyzer case made of AK7 alloy during the lost foam casting is considered. The data set acquired based on the experimental investigations has been subjected to statistical processing. The use of statistic models makes it possible to acquire the results of the influence of the holding time and content of secondary materials in the charge on strength and tightness of mentioned castings. The results of an investigation into the influence of holding the AK7 melt at the overheating temperature of 880–890°С on the content of nonmetallic inclusions in castings show that it can be regulated varying the holding time. This procedure decreases the melt microinhomogeneity and provides the acquisition of numerous castings with a minimal content of nonmetallic inclusions.     

物理富集—熔盐电解法从二次铝灰回收金属铝

二次铝灰是铝工业生产过程中产生的固体废弃物,含有金属铝、氧化铝和氮化铝等。通过球磨—筛分富集铝灰中的金属铝,研究球磨过程铝灰的粒度分布和金属铝的分离规律。结果表明,球磨后铝灰中的金属铝粒径变大,而其他盐类组分变细。较优条件是球磨3 h并筛分,粒度范围97～150μm的铝灰中金属铝的质量分数为24.51%,金属铝的质量占原料中金属铝总质量的41.40%。在冰晶石熔盐中电解最优条件下球磨—筛分后的铝灰,XRF分析表明：电解产物中Al和Si的质量分数分别为97.3%和1.6%,铝回收率为45.89%,电流效率为46.06%。     

Metallurgical and mechanical characterisation of titanium based materials for endosseous applications obtained by selective laser melting

Abstract

The aim of the present work was to estimate the feasibility of selective laser melting (SLM) to produce Ti-hydroxyapatite bioactive composite materials for personalised endosseous implants. Mixtures of Ti6Al7Nb surface conditioned powder with hydroxyapatite up to 5 vol.-% were processed by SLM with the same scanning strategy and laser power in the range of 50–200 W. Specimens with porous structures were characterised from a structural and mechanical point of view. Irrespective to the initial hydroxyapatite content, density increased by increasing the laser power. The microstructure of manufactured parts mainly consisted of α′ martensite. In materials with 5 vol.-% hydroxyapatite, a phosphorous containing phase formed as a consequence of hydroxyapatite decomposition and interaction with the base Ti alloy. By increasing the laser power, the tensile strength increased mainly due to the density improvement of all the investigated materials.     

炉渣和原材料的X射线荧光光谱快速分析

介绍了玻璃熔片X射线荧光光谱法快速分析炉渣中全铁 ,CaO ,MgO ,Al2 O3,SiO2 ,TiO2 ,MnO ,P2 O58种常规成分的方法。讨论了玻璃熔片的制备、熔片的长期稳定性和基体的吸收增强效应的校正 ;采用 2 8个国家标准物质和合成标样制作校准曲线。通过本法与标准样品的标准值和未知样品的化学法、ICP AES法的对照 ,证明了本法是一个高效、快速、准确而实用的分析方法     

Modern processes of copper concentration from mineral raw materials

The modern technologies of processing of sulfide copper raw materials using high-output autogenous and semiautogenous processes are analyzed and compared with the “dead” roasting–reduction smelting technology.