CN110818402B - 一种超细铁氧体粉末的制备方法 - Google Patents

一种超细铁氧体粉末的制备方法 Download PDF

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CN110818402B
CN110818402B CN201910765061.XA CN201910765061A CN110818402B CN 110818402 B CN110818402 B CN 110818402B CN 201910765061 A CN201910765061 A CN 201910765061A CN 110818402 B CN110818402 B CN 110818402B
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陈新彬
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Hengdian Group DMEGC Magnetics Co Ltd
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Abstract

本发明涉及超细粉料制备领域,公开了一种超细铁氧体粉末的制备方法,步骤为:(1)将铁氧体原材料在950~1050℃下预烧后得到高温预烧料;(2)将高温预烧料直接投入冷却介质中,冷却后得到粗粉碎浆料;(3)将粗粉碎浆料与辅料一起进行二次研磨,得到铁氧体浆料;(4)铁氧体浆料经喷雾干燥后即得超细铁氧体粉末。本发明将高温预烧料直接投入冷却介质中,一方面可以使高温预烧料实现快速冷却,避免有效的磁性成分被过度氧化;另一方面实现了对高温预烧料的粗粉碎,使得高温预烧料的快速冷却和粗粉粹可以同时进行,节约了降温时间和粗研磨步骤,不但可以提高铁氧体粉末的各项性能,还提高了生产效率。

Description

一种超细铁氧体粉末的制备方法
技术领域
本发明涉及超细粉料制备领域,尤其是涉及一种超细铁氧体粉末的制备方法。
背景技术
铁氧体一般是指铁族的和其他一种或多种适当的金属元素的复合氧化物。就其导电性而论属于半导体,但在应用上是作为磁性介质而被利用的。铁氧体按照其晶格类型主要可分为七类:尖晶石型、石榴石型、磁铅石型、钙钛石型、钛铁石型、氯化钠型、金红石型。按照其特性和用途可分为软磁、永磁、绝磁、矩磁、压磁等五类。由于它原材料丰富、制造成本低、性能稳定等,被广泛应用于磁记录、微波吸收、磁分离、磁密封、电子元件等各个领域,是工业生产中不可缺少的基础功能材料。
铁氧体成型坯件一般由铁氧体粉料压制成型烧结后制得,因此铁氧体粉料的粒径及表面活性等均对烧结后的铁氧体成型坯件的性能有较大影响。现有技术中制备铁氧体粉末时,一般是将铁氧体粉末在一定温度下预烧一段时间后随炉缓慢冷却,将预烧料及添加剂(或辅料)直接投到球磨机(或砂磨机)中进行研磨制备浆料,然后将浆料干燥后得到铁氧体粉末。例如,一种在中国专利文献上公开的“软磁锰锌铁氧体粉料的生产工艺”,其公告号CN100418921C,其工艺步骤是:将原材料进行湿磨后喷雾造粒,然后预烧,对预烧料进行振动球磨,然后进行二次湿磨,二次喷雾造粒。该发明由于原料在预烧前采用湿磨,预烧后采用震动球磨和二次湿磨、二次喷雾造粒,一方面有利于预烧中固相反应充分完成,提高产品起始磁导率、降低功率损耗,同时减少工作场所粉尘污染,减少产品能耗。
但采用现有技术中的方法,将预烧料随炉缓慢冷却并直接进行球磨,制备出的铁氧体粉料的粒径及表面活性仍有待提高,压制成型后烧结得到的铁氧体坯料易产生坯磁力不足、烧结粘连、烧结开裂等问题,已经不能满足市场越来越高的需求。
发明内容
本发明是为了克服现有技术中将预烧料随炉缓慢冷却并直接进行球磨,制备出的铁氧体粉料的粒径及表面活性仍有待提高,压制成型后烧结得到的铁氧体坯料易产生坯磁力不足、烧结粘连、烧结开裂的问题,提供一种超细铁氧体粉末的制备方法,制得的铁氧体粉末粒径大大减小,且表面活性高,故而能提高铁氧体坯料的磁性能,并降低铁氧体毛坯在最终烧结时的收缩率,提升产品良率。
为了实现上述目的,本发明采用以下技术方案:
一种超细铁氧体粉末的制备方法,包括如下步骤:
(1)将铁氧体原材料在950~1050℃下预烧后得到高温预烧料;
(2)将高温预烧料直接投入冷却介质中,冷却后得到粗粉碎浆料;
(3)将粗粉碎浆料与辅料一起进行二次研磨,得到铁氧体浆料;
(4)铁氧体浆料经喷雾干燥后即得超细铁氧体粉末。
以锰锌铁氧体为例,铁氧体原材料Fe2O3、Mn3O4和ZnO都是不具有磁性的金属氧化物,经过步骤(1)的预烧,在950~1050℃高温下铁氧体原材料可以进行固相反应,生成锰锌铁氧体(MnZn)Fe2O4和锰铁氧体MnFe2O4等物质,使得到的高温预烧料具有了磁性。
高温预烧料如果在空气中缓慢冷却,在不同的温度下会与氧气发生一系列反应:
1050℃:
MnFe2O4+1/4O2→Fe2O3+1/2Mn2O3
1000℃:
3MnFe2O4+1/2O2→β-Mn3O4·3Fe2O3
950℃:
2(β-Mn3O4)+1/2O2→3(α-Mn2O3)
因为高温预烧料的温度较高,所以上述反应进行的速度很快。当温度继续下降至950~600℃后,MnFe2O4会进一步被氧化,同时面心立方结构的γ-Fe2O3会脱溶析出体心立方结构的α-Fe2O3
4MnFe2O4+O2→2Mn2O3·4Fe2O3
(α-Mn2O3)·(γ-Fe2O3)→α-Mn2O3+α-Fe2O3
温度继续下降至600~500℃,MnFe2O4会几乎全部被氧化为Mn2O3和Mn3O4,剩余的Mn2+继续与氧气反应生成Mn3+
2Mn3O4+Fe2O3+1/2O2→3(α-Mn2O3)+Fe2O3
至此MnFe2O4中的Mn2+基本都被氧化为其他相,预烧料的磁性大大降低。并且,当粉料中的MnFe2O4含量过少,磁化度过低时,磁芯尺寸的收缩量就会较小,由于磁芯坯件间间隙较小,收缩量不足会使相邻的磁芯碰触在一起,熔融后导致铁氧体坯件之间表面粘在一起发生烧结粘连。最终制得的铁氧体磁性达不到使用要求,良品率也低。但同时,如果预烧料的氧化不充分,又会在铁氧体的最终烧结过程中,导致坯件重新氧化,产生热膨胀效应,发生烧结开裂现象,使产品产生裂纹。因此采取适当的冷却条件对高温预烧料进行冷却,合理控制高温预烧料的氧化程度,对于提高铁氧体的磁性能及良品率有重要作用。
本发明中为了避免高温预烧料缓慢冷却时会发生的磁性下降及烧结粘连或烧结开裂现象,将步骤(1)中得到的高温预烧料经步骤(2)直接投入冷却介质中,一方面冷却介质能隔绝高温预烧料与空气的接触,并且冷却介质和高温预烧料的温度相差大,可以使高温预烧料实现快速冷却,从而有效避免高温预烧料在高温和有氧气存在的条件下有效的磁性成分被过度氧化,导致磁性大大降低及收缩率。另一方面,将高温预烧料投入冷却介质中时,高温预烧料在快速降温过程中由于各部分收缩不均匀,会发生爆裂,实现了对高温预烧料的粗粉碎,使得高温预烧料的快速冷却和粗粉粹可以同时进行,节约了降温时间和粗研磨步骤,不但可以提高铁氧体粉末的各项性能,还提高了生产效率。
将经过快速冷却和粗粉碎后得到的粗粉碎浆料再通过步骤(3)进行二次研磨进一步
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降低其粒径,二次研磨后得到的铁氧体浆料具有粒度分布窄、粒度小(X50:0.06~1.0um),比表面积大等优点,能大幅改善提高最终制得的铁氧体的电磁特性。
作为优选,步骤(1)中的预烧时间为2~4h。预烧是铁氧体制备过程中最为重要的步骤,铁氧体原材料在预烧过程中发生一系列物理、化学反应。
以锰锌铁氧体为例,在预烧过程中,反应温度在500~600℃时,Mn2+可以氧化生成Mn3+,温度在400~700℃时,部分Fe2O3会由体心立方结构的α-Fe2O3转变为面心立方结构的γ-Fe2O3
2Mn2++1/2O2→2Mn3++O2-
2Mn3O4+1/2O2→3Mn2O3
α-Fe2O3→γ-Fe2O3
当温度继续升高至750℃时,ZnO开始与Fe2O3发生反应生成锌铁氧体ZnFe2O4,同时,在750~850℃时,一部分Mn2O3与ZnO不断进行着固溶-分解过程:
ZnO+Fe2O3→ZnFe2O4
Figure BDA0002171669660000031
继续升温至850℃时,开始发生如下反应:
3Mn2O3→2Mn3O4+1/2O2
Mn3O4+Fe2O3→MnFe2O4+Mn2O3
在生成锰铁氧体MnFe2O4的同时产生的Mn2O3继续转变为新的Mn3O4,因而不断产生新的MnFe2O4
ZnFe2O4在950℃时开始与MnFe2O4生成MnZnFe2O4
MnFe2O4+ZnFe2O4→2MnZnFe2O4
随着温度继续升高,参与上述反应的物料逐渐增多。
因此,预烧时间对铁氧体晶体的生成比例有较大影响,从而对最终铁氧体产品的性能会产生重要影响。预烧时间不足,反应不能充分进行,影响产品的磁性能并易发生烧结粘连;预烧时间过长会导致后续烧结过程易发生烧结开裂。采用本发明中的预烧时间,可以在保证产品磁性能的同时,有效避免烧结粘连和烧结开裂的发生。
作为优选,步骤(2)中所述冷却介质为0.02~0.10wt%的石灰水或去离子水。采用石灰水作为冷却介质,不仅能加快冷却速度,而且将铁氧体粉末烘干后Ca(OH)2会分解成CaO,并且均匀的分散在粉末中。使用该铁氧体粉末制备铁氧体时,铁氧体粉末在高温烧结时CaO跟SiO2的反应物均匀的分布在晶界上能大幅提高铁氧体的电阻率,降低涡流损耗,从而改善制得的铁氧体的性能。
作为优选,步骤(2)中所述的高温预烧料与冷却介质的质量比为1:(0.6~1.0)。采用该比例可以保证高温预烧料能快速冷却,并使得干燥后生成的CaO比例适中,不影响产品的性能。
作为优选,步骤(2)中冷却时间小于10s。在此冷却时间范围内,既可以保证高温预烧料冷却充分,又能保证高温预烧料中的有效成分的氧化比例,使得后续烧结过程既不会发生烧结粘连也不会发生烧结开裂。
作为优选,步骤(3)中所述的二次研磨采用湿法球磨或砂磨,料球质量比为1:(5~7)。采用该料球比进行湿法球磨或砂磨,可以保证二次研磨后的浆料粒度分布窄、粒度小、比表面积大,能大幅改善铁氧体的电磁特性。
作为优选,冷却介质为石灰水,步骤(3)中所述辅料为在铁氧体浆料中的浓度为0~0.005wt%的SiO2及0.02~0.05wt%Nb2O5和/或0.02~0.05wt%ZrO2
作为优选,冷却介质为去离子水,步骤(3)中所述辅料为在铁氧体浆料中的浓度为0~0.005wt%的SiO2、0.03~0.08wt%的CaCO3及0.02~0.05wt%Nb2O5和/或0.02~0.05wt%ZrO2
冷却介质为石灰水时,将铁氧体粉末烘干后Ca(OH)2会分解成CaO,并且均匀的分散在粉末中,添加本发明质量范围内的SiO2作为辅料时,SiO2和CaO的反应产物主要富集于晶界,提高晶界电阻,从而降低铁氧体涡流损耗。但如果SiO2添加过多,过多的SiO2会与Fe2O3反应生成Fe2(SiO3)3,其熔点为1150℃,在铁氧体的烧结过程中成为晶界液相,导致异常晶粒长大。
当冷却介质为蒸馏水时,辅料添加CaCO3和SiO2,CaCO3同样会分解成CaO与SiO2反应,提高晶界电阻,降低铁氧体涡流损耗。
同时,本发明还在辅料中添加一定质量的Nb2O5和/或ZrO2,Nb2O5和ZrO2可以细化晶粒,促进晶粒均匀致密,提高铁氧体起始磁导率和电阻率,降低材料功率损耗。而如果添加量超出本发明的范围,则会导致晶界气孔增多,铁氧体密度和电阻率降低,功耗上升。
作为优选,步骤(3)中二次研磨时间为60~90min。采用适当的研磨时间可以保证研磨后的浆料粒度符合要求。
因此,本发明具有如下有益效果:
(1)将高温预烧料直接投入冷却介质中,一方面可以使高温预烧料实现快速冷却,从而有效避免高温预烧料在高温和有氧气存在的条件下有效的磁性成分被过度氧化,导致磁性大大降低及收缩率。另一方面,将高温预烧料投入冷却介质中时,高温预烧料在快速降温过程中由于各部分收缩不均匀,会发生爆裂,实现了对高温预烧料的粗粉碎,使得高温预烧料的快速冷却和粗粉粹可以同时进行,节约了降温时间和粗研磨步骤,不但可以提高铁氧体粉末的各项性能,还提高了生产效率;
(2)将经过快速冷却和粗粉碎后的粗粉碎浆料进行二次研磨,可以进一步降低铁氧体粉末的粒径,增大比表面积,进一步提升产品的磁性能;
(3)二次研磨时添加适量的辅料,提高晶界电阻,从而降低铁氧体涡流损耗;细化晶粒,促进晶粒均匀致密,提高铁氧体起始磁导率和电阻率,降低材料功率损耗。
具体实施方式
下面结合具体实施方式对本发明做进一步的描述。
实施例1:
一种超细铁氧体粉末的制备方法,包括如下步骤:
(1)按重量百分比69.75%Fe2O3、23%Mn3O4、7.25%ZnO配制400kg MnZn功率铁氧体DMR44原材料,混合均匀后将原材料投入回转窑中在980℃下预烧3h得到高温预烧料;
(2)将高温预烧料直接投入到320kg冷却介质(浓度为0.06wt%的石灰水)中进行快速冷却,冷却5min后得到粗粉碎浆料;
(3)将粗粉碎浆料与辅料SiO2和Nb2O5一起倒入砂磨机中进行二次研磨90分钟(料:球=1:6),得到铁氧体浆料,其中SiO2和Nb2O5在铁氧体浆料中的浓度为0.003wt%和0.03wt%;
(4)铁氧体浆料经喷雾干燥后即得超细铁氧体粉末。
实施例2:
一种超细铁氧体粉末的制备方法,包括如下步骤:
(1)按重量百分比69.75%Fe2O3、23%Mn3O4、7.25%ZnO配制400kg MnZn功率铁氧体DMR44原材料,混合均匀后将原材料投入回转窑中在950℃下预烧4h得到高温预烧料;
(2)将高温预烧料直接投入到320kg冷却介质(浓度为0.06wt%的石灰水)中进行快速冷却,冷却3min后得到粗粉碎浆料;
(3)将粗粉碎浆料与辅料SiO2、Nb2O5和ZrO2一起倒入砂磨机中进行二次研磨90分钟(料:球=1:6),得到铁氧体浆料,其中SiO2、Nb2O5和ZrO2在铁氧体浆料中的浓度为0.003wt%、0.03wt%和0.03wt%;
(4)铁氧体浆料经喷雾干燥后即得超细铁氧体粉末。
实施例3:
一种超细铁氧体粉末的制备方法,包括如下步骤:
(1)按重量百分比69.75%Fe2O3、23%Mn3O4、7.25%ZnO配制400kg MnZn功率铁氧体DMR44原材料,混合均匀后将原材料投入回转窑中在1050℃下预烧2h得到高温预烧料;
(2)将高温预烧料直接投入到320kg冷却介质(浓度为0.06wt%的石灰水)中进行快速冷却,冷却10min后得到粗粉碎浆料;
(3)将粗粉碎浆料与辅料SiO2、Nb2O5和ZrO2一起倒入砂磨机中进行二次研磨90分钟(料:球=1:6),得到铁氧体浆料,其中SiO2、Nb2O5和ZrO2在铁氧体浆料中的浓度为0.005wt%、0.02wt%和0.02wt%;
(4)铁氧体浆料经喷雾干燥后即得超细铁氧体粉末。
实施例4:
一种超细铁氧体粉末的制备方法,包括如下步骤:
(1)按重量百分比69.75%Fe2O3、23%Mn3O4、7.25%ZnO配制400kg MnZn功率铁氧体DMR44原材料,混合均匀后将原材料投入回转窑中在980℃下预烧3h得到高温预烧料;
(2)将高温预烧料直接投入到240kg冷却介质(浓度为0.10wt%的石灰水)中进行快速冷却,冷却5min后得到粗粉碎浆料;
(3)将粗粉碎浆料与辅料Nb2O5和ZrO2一起倒入砂磨机中进行二次研磨60分钟(料:球=1:5),得到铁氧体浆料,其中Nb2O5和ZrO2在铁氧体浆料中的浓度为0.05wt%和0.05wt%;
(4)铁氧体浆料经喷雾干燥后即得超细铁氧体粉末。
实施例5:
一种超细铁氧体粉末的制备方法,包括如下步骤:
(1)按重量百分比69.75%Fe2O3、23%Mn3O4、7.25%ZnO配制400kg MnZn功率铁氧体DMR44原材料,混合均匀后将原材料投入回转窑中在980℃下预烧3h得到高温预烧料;
(2)将高温预烧料直接投入到400kg冷却介质(浓度为0.02wt%的石灰水)中进行快速冷却,冷却5min后得到粗粉碎浆料;
(3)将粗粉碎浆料与辅料SiO2、Nb2O5和ZrO2一起倒入砂磨机中进行二次研磨80分钟(料:球=1:7),得到铁氧体浆料,其中SiO2、Nb2O5和ZrO2在铁氧体浆料中的浓度为0.003wt%、0.03wt%和0.03wt%;
(4)铁氧体浆料经喷雾干燥后即得超细铁氧体粉末。
实施例6:
一种超细铁氧体粉末的制备方法,包括如下步骤:
(1)按重量百分比69.75%Fe2O3、23%Mn3O4、7.25%ZnO配制400kg MnZn功率铁氧体DMR44原材料,混合均匀后将原材料投入回转窑中在980℃下预烧3h得到高温预烧料;
(2)将高温预烧料直接投入到240kg冷却介质(去离子水)中进行快速冷却,冷却10min后得到粗粉碎浆料;
(3)将粗粉碎浆料与辅料SiO2、CaCO3、Nb2O5和ZrO2一起倒入砂磨机中进行二次研磨80分钟(料:球=1:6),得到铁氧体浆料,其中SiO2、CaCO3、Nb2O5和ZrO2在铁氧体浆料中的浓度为0.003wt%、0.03wt%、0.03wt%和0.03wt%;
(4)铁氧体浆料经喷雾干燥后即得超细铁氧体粉末。
实施例7:
一种超细铁氧体粉末的制备方法,包括如下步骤:
(1)按重量百分比69.75%Fe2O3、23%Mn3O4、7.25%ZnO配制400kg MnZn功率铁氧体DMR44原材料,混合均匀后将原材料投入回转窑中在980℃下预烧3h得到高温预烧料;
(2)将高温预烧料直接投入到360kg冷却介质(去离子水)中进行快速冷却,冷却10min后得到粗粉碎浆料;
(3)将粗粉碎浆料与辅料SiO2、CaCO3、Nb2O5和ZrO2一起倒入砂磨机中进行二次研磨80分钟(料:球=1:6),得到铁氧体浆料,其中SiO2、CaCO3、Nb2O5和ZrO2在铁氧体浆料中的浓度为0.005wt%、0.05wt%、0.03wt%和0.03wt%;
(4)铁氧体浆料经喷雾干燥后即得超细铁氧体粉末。
实施例8:
一种超细铁氧体粉末的制备方法,包括如下步骤:
(1)按重量百分比69.75%Fe2O3、23%Mn3O4、7.25%ZnO配制400kg MnZn功率铁氧体DMR44原材料,混合均匀后将原材料投入回转窑中在980℃下预烧3h得到高温预烧料;
(2)将高温预烧料直接投入到360kg冷却介质(去离子水)中进行快速冷却,冷却10min后得到粗粉碎浆料;
(3)将粗粉碎浆料与辅料SiO2、CaCO3、Nb2O5和ZrO2一起倒入砂磨机中进行二次研磨80分钟(料:球=1:6),得到铁氧体浆料,其中SiO2、CaCO3、Nb2O5和ZrO2在铁氧体浆料中的浓度为0.003wt%、0.08wt%、0.03wt%和0.03wt%;
(4)铁氧体浆料经喷雾干燥后即得超细铁氧体粉末。
对比例1:
一种铁氧体粉末的制备方法,包括如下步骤:
(1)按重量百分比69.75%Fe2O3、23%Mn3O4、7.25%ZnO配制400kg MnZn功率铁氧体DMR44原材料,混合均匀后将原材料投入回转窑中在980℃下预烧3h得到高温预烧料,并随炉冷却得预烧料;
(2)将预烧料与辅料CaCO3、SiO2、Nb2O5一起倒入砂磨机中进行二次研磨90分钟(料:球=1:6),得到铁氧体浆料,其中CaCO3、SiO2、Nb2O5在铁氧体浆料中的浓度为0.06wt%、0.003wt%、0.03wt%;
(3)铁氧体浆料经喷雾干燥后即得铁氧体粉末。
对比例2:
一种铁氧体粉末的制备方法,包括如下步骤:
(1)按重量百分比69.75%Fe2O3、23%Mn3O4、7.25%ZnO配制400kg MnZn功率铁氧体DMR44原材料,混合均匀后将原材料投入回转窑中在950℃下预烧4h得到高温预烧料,并随炉冷却得预烧料;
(2)将预烧料与辅料CaCO3、SiO2、Nb2O5和ZrO2一起倒入砂磨机中进行二次研磨90分钟(料:球=1:6),得到铁氧体浆料,其中CaCO3、SiO2、Nb2O5和ZrO2在铁氧体浆料中的浓度为0.06wt%、0.003wt%、0.03wt%和0.03wt%;
(3)铁氧体浆料经喷雾干燥后即得铁氧体粉末。
对比例3:
一种铁氧体粉末的制备方法,包括如下步骤:
(1)按重量百分比69.75%Fe2O3、23%Mn3O4、7.25%ZnO配制400kg MnZn功率铁氧体DMR44原材料,混合均匀后将原材料投入回转窑中在1050℃下预烧2h得到高温预烧料,并随炉冷却得预烧料;
(2)将预烧料与辅料CaCO3、SiO2、Nb2O5和ZrO2一起倒入砂磨机中进行二次研磨90分钟(料:球=1:6),得到铁氧体浆料,其中CaCO3、SiO2、Nb2O5和ZrO2在铁氧体浆料中的浓度为0.06wt%、0.005wt%、0.02wt%和0.02wt%;
(3)铁氧体浆料经喷雾干燥后即得铁氧体粉末。
将上述实施例和对比例中制得的超细铁氧体粉末及铁氧体粉末经压制成型、烧结后制得标准样环φ25x15x6,对相应的粉末及标准样环进行性能测试,测试结果如表1所示。
表1:铁氧体粉末及标准样环φ25x15x6性能测试结果。
Figure BDA0002171669660000091
注:测试条件如下:
μi:f=1KHz,25℃;
Bs:f=50Hz,100℃,H=1194A/m;
Pcv:f=100KHz,100℃,Bm=200mT。
从表1中可以看出,实施例1-8采用本发明中的方法,制得的超细铁氧体粉末的粒度和比表面积与对比例1-3中相比,均有明显提升。且用实施例1-8中的超细铁氧体粉末制得的样环的起始磁导率μi、饱和磁感应强度Bs均比对比例1-3中有所提高,证明采用本发明的方法可以有效提高产品的磁性能。同时实施例1-8中制得的样环的功率损耗Pcv均小于对比例1-3中制得的样环,证明采用本发明的方法可以提高产品的良品率。

Claims (7)

1.一种超细铁氧体粉末的制备方法,其特征是,包括如下步骤:
(1)将铁氧体原材料在 950~1050℃下预烧后得到高温预烧料;
(2)将高温预烧料直接投入冷却介质中,冷却后得到粗粉碎浆料,所述冷却介质为质量浓度为0.02~0.10%的石灰水;
(3)将粗粉碎浆料与辅料一起进行二次研磨,得到铁氧体浆料;
(4)铁氧体浆料经喷雾干燥后即得超细铁氧体粉末。
2.根据权利要求1所述的一种超细铁氧体粉末的制备方法,其特征是,步骤(1)中的预烧时间为2~4h。
3.根据权利要求1所述的一种超细铁氧体粉末的制备方法,其特征是,步骤(2)中所述的高温预烧料与冷却介质的质量比为1:(0.6~1.0)。
4.根据权利要求1所述的一种超细铁氧体粉末的制备方法,其特征是,步骤(2)中冷却时间小于10s。
5.根据权利要求1所述的一种超细铁氧体粉末的制备方法,其特征是,步骤(3)中所述的二次研磨采用湿法球磨或砂磨,料球质量比为1:(5~7)。
6.根据权利要求1所述的一种超细铁氧体粉末的制备方法,其特征是,步骤(3)中所述辅料包括在铁氧体浆料中的浓度为0~0.005wt% 的SiO2,还包括在铁氧体浆料中的浓度为0.02~0.05wt%的 Nb2O5和0.02~0.05wt%的 ZrO2中的一种或两种。
7.根据权利要求1或4或5所述的一种超细铁氧体粉末的制备方法,其特征是,步骤(3)中二次研磨时间为60~90min。
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