Small sized alpha alumina particles and platelets
    1.
    发明授权
    Small sized alpha alumina particles and platelets 失效
    小尺寸的α氧化铝颗粒和血小板

    公开(公告)号:US5149520A

    公开(公告)日:1992-09-22

    申请号:US460844

    申请日:1990-01-31

    IPC分类号: C01F7/14 C01F7/44

    摘要: A process for producing alpha alumina particles includes steps of precipitating alumina hydrate from an aqueous sodium aluminate solution by treatment with alumina hydrate seed material and alpha alumina promoter particles; and calcining the precipitated alumina hydrate in the presence of a mineralizer. A preferred mineralizer is aluminum fluoride. The process produces alpha alumina particles having a plate-like shape and an average size of less than about 1.5 microns.

    摘要翻译: PCT No.PCT / US89 / 02659 Sec。 371日期1990年1月31日第 102(e)日期1990年1月31日PCT 1989年6月19日PCT。一种生产α氧化铝颗粒的方法包括通过用氧化铝水合物种子材料和α氧化铝促进剂颗粒处理从铝酸钠水溶液中沉淀氧化铝水合物的步骤; 并在矿化剂存在下煅烧沉淀的氧化铝水合物。 优选的矿化剂是氟化铝。 该方法产生具有板状形状和平均尺寸小于约1.5微米的α氧化铝颗粒。

    Noncollapsible ceramic foam
    3.
    发明授权
    Noncollapsible ceramic foam 失效
    不可折叠陶瓷泡沫

    公开(公告)号:US4356271A

    公开(公告)日:1982-10-26

    申请号:US254926

    申请日:1981-04-16

    IPC分类号: C04B28/34 C04B21/00

    CPC分类号: C04B28/06 C04B28/342

    摘要: A lightweight, porous, ceramic material is made by mixing a slurry containing a foaming agent until a constant volume of foam is achieved. The foam is then pumped or poured into a mold or form where it sets up into a cellular structure. The formed foam is then cured, dried and heated at elevated temperatures. The slurry used in making the foam is made from ceramic particles, water, foaming agent and bonding materials. The bonding materials function to provide an initial bond as the foam is generated to prevent foam collapse, a low temperature bond after the foam structure is set, cured and dried, and a final bond after heating to elevated temperatures. In a preferred embodiment, the ceramic particles used are alumina.

    摘要翻译: 轻质,多孔的陶瓷材料是通过混合含有发泡剂的浆料制成的,直到达到恒定体积的泡沫。 然后将泡沫泵送或倒入模具或其中其设置成细胞结构的形式。 然后将形成的泡沫体固化,干燥并在高温下加热。 用于制造泡沫的浆料由陶瓷颗粒,水,发泡剂和粘结材料制成。 粘合材料的作用是提供初始粘结,因为产生泡沫以防止泡沫破裂,在泡沫结构被固化和干燥之后的低温粘结,以及加热到升高的温度之后的最终粘合。 在优选的实施方案中,使用的陶瓷颗粒是氧化铝。

    Low temperature mineralization of alumina
    4.
    发明授权
    Low temperature mineralization of alumina 有权
    氧化铝低温矿化

    公开(公告)号:US06203773B1

    公开(公告)日:2001-03-20

    申请号:US09351968

    申请日:1999-07-12

    IPC分类号: C01F702

    摘要: Alpha alumina particles are made by heating particles of alumina with an aqueous solution containing a dissolved fluorine-containing compound and an acid; separating the particles from the solution and then calcining the particles at a temperature not greater than about 1025° C. The alumina particles preferably have an LOI in the range of about 1-20 wt. %; more preferably about 1-6 wt. %. Alpha alumina particles of the invention are more readily ground into smaller particles than alpha alumina particles made by calcining at higher temperatures. The remaining soda in the alpha alumina is found to be highly soluble in hot water. The process produces low soda content (0.01 wt. % Na2O or less) alpha alumina crystals from alumina feedstocks with 0.5 wt. % or more initial soda levels. The alpha alumina crystals produced are as large as 30-40 microns. Most typically; the size range is between 2 and 8 microns. Because of the low mineralization temperature, the particles require significantly less grinding time to separate the component alpha crystals.

    摘要翻译: 通过用含有溶解的含氟化合物和酸的水溶液加热氧化铝颗粒来制备α-氧化铝颗粒; 将颗粒与溶液分离,然后在不大于约1025℃的温度下煅烧颗粒。氧化铝颗粒优选具有约1-20重量%的LOI。 %; 更优选约1-6wt。 %。 本发明的α氧化铝颗粒比通过在较高温度下煅烧制备的α氧化铝颗粒更容易研磨成较小的颗粒。发现α氧化铝中的剩余苏打在高温下可溶于热水。 该方法从0.5重量%的氧化铝原料产生低苏打含量(0.01重量%Na 2 O或更少)的α氧化铝晶体。 初始苏打水平的百分比以上。 产生的α氧化铝晶体大至30-40微米。 最典型的 尺寸范围在2到8微米之间。 由于矿化温度低,颗粒需要明显较少的研磨时间来分离组分α晶体。