氟化铵和氨循环法从脱腊脱油废白土中制取白炭黑

The ammonium fluoride and ammonia closed cycle method for white carbon black production from dewaxed and deoiled waste clay.

利用ＮＨ４Ｆ与废白土中ＳｉＯ２反应生成的（ＮＨ４）ＳｉＦ６溶液和ＮＨ３，进行闭路循环反应，生成ＮＨ４Ｆ与水合ＳｉＯ２（白炭黑），通过正交优化，得到最佳工艺为：氟化反应，ＮＨ４Ｆ∶废白土＝１．２８，ＮＨ４Ｆ∶水＝０．９，反应温度６０℃，反应时间４ｈ；氨化反应，反应温度６０℃，反应时间８ｈ，投料比＝２〔２５％氨水ｍＬ／（ＮＨ４）ＳｉＦ６ｇ〕。循环试验结果表明，ＮＨ４Ｆ转化率可达８２％，白炭黑产率达９０％以上，只需补充少量ＮＨ４Ｆ和氨水，就能在不产生环境污染的情况下从废白土中制取白炭黑。

A closed cycle method for producing ammonium fluoride and hydrated silicon dioxide ( white carbon black) was practiced by using ammonium fluosilicate solution and ammonia gas,both produced from ammonium fluoride reacted with silicon dioxide of waste clay. The optimum conditions are: ammonium fluoride/waste clay = 1.28, ammonium fluoride/water = 0.9, T = 60℃ and t = 4h for ammonium fluoride reaction; T = 60℃, t = 8h and feeding ratio = 2 ( 25% ammonia liquid mL/ammonium fluosilicate g ) for ammonia reaction. The experimental results show that the conversion ratio of ammonium fluoride reaches 82% and the white carbon black production rate is over 90%. So, the white carbon black could be made from waste clay without environmental pollution so long as a little amount of ammonium fluoride and ammonia was added for each cycle.