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1.发明授权公开(公告)号：US07244404B2
公开(公告)日：2007-07-17
申请号：US10798333
申请日：2004-03-12
IPC分类号： C01F7/00
摘要： A process for the removal and causticisation of sodium oxalate and/or sodium sulphate from a Bayer process liquor containing sodium carbonate and one or both of sodium oxalate and sodium sulphate in an alumina refinery is described. The process is based on the observation that to efficiently causticise sodium oxalate solutions, it is first necessary to remove the aluminate ion from solution, optionally with recovery of the aluminate ion in some later step. This is effected by removing aluminate ions from the Bayer liquor through the formation of a carbonate bearing hydrocalumite and/or sulpha-bearing hydrocalumite. The liquor may then be treated with sufficient lime to remove and causticise any residual carbonate ions and some or all of the oxalate ions present so that any reacted lime solids thus formed can be separated and safely disposed of. The process may include a pre-causticisation step in which the Bayer liquor is first causticised to reduce the concentration of carbonate ions, prior to the step of removing aluminate ions. The invention provides an effective process for the removal of sodium sulphate and a practical method for the recovery of soda from sodium sulphate. The efficiency of lime utilisation can also be dramatically increased from about 20% to 80% (if sulphate removal is not the objective) wherein alumina losses can be minimised. The oxalate concentration of the process liquor is also substantially lower than can usually be achieved in processes based on sodium oxalate-crystallisation.
摘要翻译： 描述了在氧化铝精炼厂中从含有碳酸钠和一种或两种草酸钠和硫酸钠的拜耳法处理液中去除和苛化草酸钠和/或硫酸钠的方法。 该方法基于以下观察：为了有效地苛化草酸钠溶液，首先需要从溶液中除去铝酸根离子，任选地在稍后的步骤中回收铝酸根离子。 这是通过从形成含有碳酸钙的含水硅钙石和/或含水硅钙土的拜耳液中除去铝酸盐离子来实现的。 然后可以用足够的石灰处理液体以除去和苛化任何残留的碳酸根离子和存在的一些或全部草酸根离子，使得由此形成的任何反应的石灰固体可被分离并安全地处理。 该方法可以包括预苛化步骤，其中在去除铝酸根离子的步骤之前，首先将拜耳液体苛化以降低碳酸根离子的浓度。 本发明提供了一种去除硫酸钠的有效方法和从硫酸钠中回收苏打的实用方法。 石灰利用的效率也可以从约20％显着增加到80％（如果硫酸盐去除不是目标），其中氧化铝损失可以最小化。 处理液的草酸盐浓度也显着低于通常在基于草酸钠结晶的方法中实现的草酸盐浓度。
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2.发明授权Process for the removal of anionic impurities from caustic aluminate solutions 失效从苛性铝酸盐溶液中除去阴离子杂质的方法公开(公告)号：US07691348B2
公开(公告)日：2010-04-06
申请号：US10474627
申请日：2002-04-10
IPC分类号： C01F7/00
摘要： A process for removing anionic impurities from a caustic aluminate solution having aqueous tetrahydroxy aluminate ions is described. A caustic aluminate solution is obtained such that anionic impurities are partially or substantially substituted into tetrahydroxy aluminate ions to form substituted aluminate ions. A suitable calcium compound, such as quicklime, is reacted in a conventional slaker (10) with a slaking solution, for example water, and stored in an agitated storage tank (12). The resulting slurry is pumped to a reaction vessel (14) where it is reacted with a caustic aluminate solution under appropriate conditions such that the calcium compound is converted into tricalcium aluminate (TCA) precipitate. Upon reaction substituted aluminate ions are substantially incorporated within the TCA precipitate to form a substituted TCA precipitate enabling the anionic impurities to be removed from the solution via the substituted TCA precipitate for disposal or recovery. The caustic aluminate liquor may be optionally fortified with an anionic impurity by mixing it in a mixing tank (16) with the anionic impurity.
摘要翻译： 描述了从具有四羟基铝酸根离子水溶液的苛性铝酸盐溶液中除去阴离子杂质的方法。 获得苛性铝酸盐溶液，使得阴离子杂质部分或基本上被四羟基铝酸盐离子取代以形成取代的铝酸根离子。 合适的钙化合物，例如生石灰，在常规的洗涤剂（10）中与澄清溶液（例如水）反应，并储存在搅拌的储存罐（12）中。 将所得浆液泵送到反应容器（14）中，在适当的条件下使其与苛性铝酸盐溶液反应，使得钙化合物转化为三钙铝酸盐（TCA）沉淀物。 当反应取代的铝酸根离子基本上并入TCA沉淀物中以形成取代的TCA沉淀物时，可以通过经取代的TCA沉淀物从溶液中除去阴离子杂质用于处置或回收。 苛性铝酸盐液体可以通过在混合罐（16）中与阴离子杂质混合来任选地用阴离子杂质强化。
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3.发明授权公开(公告)号：US06743403B1
公开(公告)日：2004-06-01
申请号：US09936781
申请日：2001-09-18
IPC分类号： C01F702
摘要： A process for the removal and causticisation of sodium oxalate and/or sodium sulphate from a Bayer process liquor containing sodium carbonate and one or both of sodium oxalate and sodium sulphate in an alumina refinery is described. The process is based on the observation that to efficiently causticise sodium oxalate solutions, it is first necessary to remove the aluminate ion from solution, optionally with recovery of the aluminate ion in some later step. This is effected by removing aluminate ions from the Bayer liquor through the formation of a carbonate-bearing hydrocalumite and/or sulphate-hearing hydrocalumite. The liquor may then be treated with sufficient lime to remove and causticise any residual carbonate ions and some or all of the oxalate ions present so that any reacted lime solids thus formed can be separated and safely disposed of. The process may include a pre-causticisation step in which the Bayer liquor is first causticised to reduce the concentration of carbonate ions, prior to the step of removing aluminate ions. The invention provides an effective process for the removal of sodium sulphate and a practical method for the recovery of soda from sodium sulphate. The efficiency of lime utilisation can also be dramatically increased from about 20% to 50% (if sulphate removal is not the objective) wherein alumina losses can be minimised. The oxalate concentration of the process liquor is also substantially lower than can usually be achieved in processes based on sodium oxalate-crystallisation.
摘要翻译： 描述了在氧化铝精炼厂中从含有碳酸钠和一种或两种草酸钠和硫酸钠的拜耳法处理液中去除和苛化草酸钠和/或硫酸钠的方法。 该方法基于以下观察：为了有效地苛化草酸钠溶液，首先需要从溶液中除去铝酸根离子，任选地在稍后的步骤中回收铝酸根离子。 这是通过形成含碳酸酯的水煤钙矿和/或硫酸盐 - 听力水泥钙矿来从拜耳液中除去铝酸盐离子来实现的。 然后可以用足够的石灰处理液体以除去和苛化任何残留的碳酸根离子和存在的一些或全部草酸根离子，使得由此形成的任何反应的石灰固体可被分离并安全地处理。 该方法可以包括预苛化步骤，其中在去除铝酸根离子的步骤之前，首先将拜耳液体苛化以降低碳酸根离子的浓度。 本发明提供了一种去除硫酸钠的有效方法和从硫酸钠中回收苏打的实用方法。 石灰利用的效率也可以从约20％显着增加到50％（如果硫酸盐去除不是目标），其中可以最小化氧化铝损失。 处理液的草酸盐浓度也显着低于通常在基于草酸钠结晶的方法中实现的草酸盐浓度。
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