【作者】 于成峰；

【导师】 高晋生；

【作者基本信息】 华东理工大学 ， 化学工艺， 2011， 博士

【摘要】 近年来,软磁功率铁氧体材料进一步向高频、高磁导率和低损耗发展,电子元器件的小型化、片式化、轻型化是大势所趋。软磁功率铁氧体原料中氧化铁的质量百分比约为70%,所以要制造高档软磁功率铁氧体材料,氧化铁原料必须满足相应的性能要求。生产高等级软磁铁氧体材料所需要的原材料氧化铁的纯度也越来越高。目前,软磁铁氧体材料制造企业所需要的氧化铁原料,主要来自钢铁厂冷轧酸洗盐酸再生过程中喷雾焙烧所产生的氧化铁粉。在氧化铁粉生产过程中往往会引入铝、硅、硫、锰、镁、钾、钠、磷、铬、镍、铜、磷等元素,某些钢铁产品的生产过程中还会引入硼、钙、钛、铌、钒等元素。本文将主要对酸再生氧化铁粉提纯的相关技术、氧化铁粉的质量检测技术、MnZn铁氧体材料中B元素微量掺杂和氧化铁粉及MnZn铁氧体材料的穆斯堡尔谱进行研究。本文研究了酸洗废液絮凝剂除硅的相关影响因素。对絮凝剂溶液浓度、絮凝剂溶液使用量、絮凝反应温度、搅拌速率及搅拌时间等进行了试验,确定了较为合适的絮凝除硅工艺条件。此外,还研究了除硅过程的动力学,求得的表观活化能表明,该过程由物理因素控制。上述研究为进一步水洗制备高纯氧化铁粉创造了条件。对除硅后的酸再生氧化铁粉水洗提纯技术进行了研究,对水洗工艺的研磨方式、料水比及搅拌时间、压滤机及滤布选择、烘干方式等进行了试验,确定了合适的水洗工艺条件。氧化铁产品质量达到GB/T 24244-2009《铁氧体用氧化铁》标准中一级品,即YHT1的要求,氧化铁粉的Fe203含量达到99.40%以上。利用水洗后的氧化铁粉制备了MnZn铁氧体试验材料,主要磁性能指标表明其质量不亚于进口的高质量氧化铁粉。本文还对氧化铁粉中氯、铝、硅、硫、钙、锰、硼、钛、镁、钾、钠、磷、铬、镍和铜等微量元素含量的测试方法进行了研究。详细探讨了各种因素对最终测试结果的影响,得出了合理的测试条件,分别建立了离子色谱法测定氧化铁粉中氯化物及ICP-AES法测定氧化铁粉中铝、硅、硫、钙、锰、硼、钛、镁、钾、钠、磷、铬、镍和铜等含量的分析方法。对MnZn铁氧体的晶体结构及其金属离子分布情况进行了分析,确定了MnZn铁氧体制备所使用的方法。根据生产实际,本试验选择了普通干法工艺来制备MnZn铁氧体。详细研究了B掺杂对MnZn铁氧体性能的影响,根据对不同B元素掺杂含量对MnZn铁氧体样品磁性能及微观结构影响的研究,表明当B掺杂含量低于10μg/g时,MnZn铁氧体材料的功率损耗、磁导率及密度较好,显微结构为适宜的细晶粒结构；当B掺杂含量高于15μg/g时,则导致MnZn铁氧体材料的密度下降,磁性能急剧恶化,微观结构表现为巨晶。通过理论计算,得出不同H3BO3掺杂水平下,相应的MnZn铁氧体粉体颗粒上原子覆盖层,分析了不同原子覆盖层对MnZn铁氧体粉体微观结构及晶粒尺寸的影响。对冷轧钢板厂应用鲁特纳法工艺生产的进口和国产两类酸洗氧化铁粉样品进行了穆斯堡尔谱分析研究。两类样品具有相近的穆斯堡尔谱及参数,穆斯堡尔谱的四极分裂都较小,表明氧化铁粉铁周围的电场对称性较好。氧化铁粉和MnZn铁氧体材料的穆斯堡尔谱及参数表明,相比于主要原料氧化铁,MnZn铁氧体中的磁性相Fe周围的配位环境已经改变,并且随着MnZn铁氧体中锰含量比例的降低,二线谱的比例显著增加。不论是MnZn铁氧体A还是MnZn铁氧体B,经热处理后,它们的穆斯堡尔谱双峰的面积都有所减小,均出现了两套以上的六线子谱,且它们的超精细场相差较大,说明锰和锌在样品中的分布在微观上是不均匀的。在对酸再生氧化铁粉提纯及应用技术研究的基础上,完成了GB/T 24244-2009《铁氧体用氧化铁》国家标准的制定工作。标准的技术指标先进合理,适用性和前瞻性强,将有利地促进我国铁氧体用氧化铁生产和使用技术的进步。更多还原

【Abstract】 In recent years, soft magnetic ferrite materials have been devoleping in the field of their functional properties such as high-frequency, high permeability and low loss. Therefore, miniaturization and light-duty of the electric components is a significant developing trend. The mass percentage of iron oxides is about 70% in the soft magnetic ferrite materials, and the raw material of iron oxides must meet the corresponding performance requirements. In order to product high-grade soft magnetic ferrite materials, the purity of iron oxides in the raw materials is required higher and higher. At present, the raw materials of iron oxide needed for the production of high-grade soft ferrite materials are mainly from iron oxide powders by spray roasting of the regeneration hydrochloric acids in cold-rolled steel plants. During iron oxide powder production process, these elements such as aluminum, silicon, sulfur, manganese, magnesium, potassium, sodium, phosphorus, chromium, nickel, copper and phosphorus are imported. Simultaneously, boron, calcium, titanium, niobium, vanadium and other elements are also introduced in the product process of some steel products. This thesis will focus on these studies on the relative purification technology of iron oxide powders from regeneration acids, the quality test technology of the iron oxide powders and the Mossbauer analysis of iron oxide powders and MnZn ferrite materials contaning a trace of B.The influencing factors related to the removing silicon of acid washing waste liquors by the flocculation were investigated. These included the concentration of flocculant solutions, the loading of flocculant solutions, the reaction temperature, the stirring rate and the stirring time. Through these experiments, the feasible technical conditions of removing silicon were confirmed. The removal ratio of silicon was up to 83%, which ensured the high purity of iron oxide powders. In addition, the kinetics of removing silicon process was also investigated. The calculated apparent active energy indicated that the process was controlled by physical factors. The above investigations provided the conditions for the preparation of iron oxide powders with high purity by further water washing.The water washing technology of iron oxide powders from the regeneration acid liquors with the removal of silicon was studied. The investigations included the grinding mothed, the ratio of raw material and water, the stirring time, the selection of filtration equipments and the drying method. Through these investigations, the feasible technical conditions of water washing were confirmed. According to the standard GB/T 24244-2009 (iron oxide powders as the raw materials of ferrite materials), the product of iron oxide powders reached to the first level (the standard of YHT1). And the content of Fe2O3 in iron oxide powders was above 99.40%. MnZn ferrite samples were also prepared using iron oxide powders by water washing as the raw materials. The main magnetic properties of the sample showed that its quality was superior to that of the imported iron oxide powder.The testing and analysis methods on the contents of chlorine, aluminum, silicon, sulfur, calcium, manganese, boron, titanium, magnesium, potassium, sodium, phosphorus, chromium, nickel, copper and other trace elements in iron oxide were studed. Various influencing factors on the final results were discussed in detail. From the results of the above discussions, the reasonable test conditions were obtained. The ion chromatography and ICP-AES method could be separately used to determine the content of chloride and the contents of aluminum, silicon, sulfur, calcium, manganese, boron, titanium, magnesium, potassium, sodium, phosphorus, chromium, nickel and copper in iron oxide powders.The preparation routes of MnZn ferrite materials were confirmed by the analysis of their crystalline structures and metal distributions. According to the actural production experiences, the technical process of ordinary drying method was used to prepare MnZn ferrite materials. The effects of the addition of B on the maganetic properties and microstructures of MnZn ferrite materials were investigated in detail. Below 10μg/g, the maganetic properties (power loss, initial permeability and density) of the samples were excellent and the microstructures of the samples presented fine crystals. Above 15μg/g, the maganetic properties of the samples decreased and the microsturctures of the samples presented giant crystals. Thruogh the theoretic calculation, the resuts on the atomic covering-layer on the MnZn ferrite particles at different additions of B were obtained. At the same time, the effects of different atomic covering-layer on the microsturctures and crystal sizes of MnZn ferrite materials were analyzed.The properties of imported and domestic iron oxide powders were analyzed by the Mossbauer. The results showed that the two kinds of samples presented the similar Mossbauer spectra and parameters and the Mossbauer quadrupole splitting value of the two samples were relatively small, which suggested that the symmetry of the electric field around iron oxide powders was good. The Mossbauer spectra and parameters suggested that the coordination environment around magnetic phase of Fe in MnZn ferrite materials was different from that in original iron oxide powders, and a high-proportion of doublet spectra was observed with a decreasing concentration of Mn in MnZn ferrite materials. For MnZn ferrite A or MnZn ferrites B, after the heat-treatment, their double peak areas were all reduced, both presented more than two Sextet sub-spectrums, and their differences in super-fine field were relatively large. These indicated that the distributions of Mn and Zn in the microsturctures were inhomogeneous in MnZn ferrite samples.Based on the researches on purification and application of iron oxide powers from regenerated hydrochloric acids in cold rolling, the national standard GB/T 24244-2009 (iron oxide powders as the raw materials of ferrite materials) were established. Its technical indexed were advanced and reasonable. In addition, it was a precursor for a strong applicability, and could advantageously promote the development of the production technology of ferrite materials from iron oxides in our country.更多还原