碳酸钙渣悬浮态煅烧试验及工业应用研究

Research on suspended calcining technology and industrial application of calcium carbonate residue

碳酸钙渣是利用磷石膏制备硫酸铵时排放出的废渣,其主要矿物成分是碳酸钙,通过煅烧可以得到高活性石灰进行再利用.利用高固气比悬浮态煅烧技术,对碳酸钙渣快速煅烧工艺进行了中试试验,得到表观分解率为95％以上的煅烧产品,且表现出较高的活性;在此基础上,与贵州瓮福磷肥厂合作采用高固气比悬浮煅烧-快速冷却技术建成一条碳酸钙渣制备活性石灰的工业试验线,产品中氧化钙的质量分数最高可达到59％,碳酸钙分解率在97.7％以上,产品的活性高,多数集中在160～180 s.系统烧成热耗为4402 kJ/kg,能耗及产品质量均优于传统工艺.

Calcium carbonate residue is a waste residue discharged in the ammonium sulfate production from phosphogyp- sum.Its main mineral composition is calcium carbonate, which can be converted into high-activity lime by calcination process. This research used high solid/gas ratio suspended calcining technology to process calcium earbonate residue in a pilot scale test.Results showed that under suspension calcining process,the apparent decomposition rate of CaCO3 in product could reach more than 95% and also with high activity.On basis of that,an industrial scale active lime production line using sus- pended calcining-rapid cooling technology with high solid/gas ratio was built by cooperating with Guizhou Wengfu Phosphate Fertilizer Plant. The mass fraction of CaO in product was as high as 59% ,the apparent decomposition rate of CaCO3 reached 97.7%, and also a high activity focused at 160- 180 s.Comparing with the traditional firing device, suspended calcining had a better thermal efficiency （energy consumption： 4 402 kJ/kg） and product quality.