Silicone rubber absorbs water vapor or other organic substances in the medium during use, and its adsorption capacity decreases, so it can be reused after regeneration.

1. Regeneration after silica gel adsorbs water vapor

After silica gel absorbs water, it can be removed by thermal desorption. There are many heating methods, such as electric furnace, flue waste heat heating and hot air drying.

The temperature of de-adding heat should be controlled at 120-180℃. For blue gel indicator, discoloration silica gel, and DL type blue silica gel, the temperature should be controlled at 100-120℃. The maximum temperature during regeneration of various industrial silica gels should not exceed the following limits:

coarse-pored silica gel shall not be higher than 600℃;

fine-pored silica gel shall not be higher than 200℃;

blue glue indicator (or discoloration silica gel) shall not be higher than 120℃;

silica-alumina glue shall not be higher than 350℃.

After regenerated silica gel, its moisture content is generally controlled below 2% before being put into use again.

2. Regeneration of silica gel after adsorbing organic impurities

⒈ roasting method

For coarse-pored silica gel, it can be placed in a baking furnace to gradually increase the temperature to 500-600℃, and it will take about 6-8 hours until the rubber particles are white or yellowish brown. For fine-pored silica gel, the firing temperature should not exceed 200°C.

⒉ rinsing method

The silica gel is soaked and rinsed in hot water after being adsorbed in saturated water vapor to reach saturation, and can be combined with detergent to remove waste oil or other organic impurities, and then washed with clean water and dried and dehydrated.

⒊ solvent flushing method

According to the type of organic matter adsorbed by silica gel, select an appropriate solvent to dissolve the organic matter adsorbed in the silica gel, and then heat the silica gel to remove the solvent.

Three, the problems that should be paid attention to in the regeneration of silica gel

⒈When drying and regenerating, pay attention to gradually increasing the temperature, so as to avoid violent drying causing the rubber particles to burst and reduce the recovery rate.

⒉When calcining and regenerating silica gel, too high temperature will cause changes in the pore structure of silica gel, which will significantly reduce its adsorption effect and affect its use value. For blue gel indicator or color-changing silica gel, the temperature of desorption and regeneration should not exceed 120℃, otherwise the color development effect will be lost due to the gradual oxidation of the color developer.

⒊ The regenerated silica gel should generally be sieved to remove fine particles to make the particles uniform.

硅胶再生重复利用方法

硅胶在使用过程中因吸附了介质中的水蒸汽或其他有机物质，吸附能力下降，可通过再生后重复使用。

一、硅胶吸附水蒸汽后的再生

硅胶吸附水份后，可通过热脱附方式将水份除去，加热的方式有多种，如电热炉、烟道余热加热及热风干燥等。

脱附加热的温度控制在120--180℃为宜，对于蓝胶指示剂、变色硅胶、DL型蓝色硅胶则控制在100--120℃为宜。各种工业硅胶再生时的*高温度不应超过以下限度：

粗孔硅胶不得高于600℃；

细孔硅胶不得高于200℃；

蓝胶指标剂（或变色硅胶）不得高于120℃；

硅铝胶不得高于350℃。

再生后的硅胶，其水份一般控制在2%以下即可重新投入使用。

二、硅胶吸附有机杂质后的再生

⒈ 焙烧法

对于粗孔硅胶，可放在焙烧炉内逐渐升温至500--600℃，约经6—8小时至胶粒呈白色或黄褐色即可。对细孔硅胶，焙烧温度不能超过200℃。

⒉ 漂洗法

将硅胶在饱和水蒸汽中吸附达到饱和后放热水中浸泡漂洗，并可结合使用洗涤剂以除去废油或其它有机杂质，再经净水洗涤后烘干脱水。

⒊ 溶剂冲洗法

根据硅胶吸附有机物种类，选用适当的溶剂将吸附在硅胶内的有机物溶出，然后将硅胶加热以脱除溶剂。

三、硅胶再生应注意的问题

⒈烘干再生时应注意掌握逐渐提高温度，以免剧烈干燥引起胶粒炸裂，降低回收率。

⒉对硅胶焙烧再生时，温度过高会引起硅胶孔结构的变化而明显降低其吸附效果，影响使用价值。对于蓝胶指示剂或变色硅胶，脱附再生的温度应不超过120℃，否则会因显色剂逐步氧化而失去显色作用。

⒊经再生后的硅胶一般应过筛除去微细颗粒，以使颗粒均匀。