铁矿浆过滤回水管道结垢物形成机制

Formation mechanism of scale in iron ore slurry filtration backwater pipe

国内A选矿厂使用R31助滤剂代替部分硫酸助滤剂对铁矿浆进行过滤脱水,发现滤液回水管道形成明显的结垢物。为查明结垢物形成的化学反应原理,通过X射线衍射分析确定了结垢物物相为碳酸钙。采用荧光分析法对不同滤液的元素组成进行定量分析,同时结合碳酸钙生成模拟实验,结果表明,R31滤液与硫酸滤液混合后,CO^2-3与Ca^2+反应生成CaCO3沉淀。CO3^2-来源为R31助滤剂滤液中羧基(-COOH),其在碱性条件下发生脱羧反应产生CO2,CO2遇水生成CO3^2-;Ca^2+的来源为过滤时硫酸与铁矿物中的含钙物质发生反应形成大量的Ca^2+。最终,揭示了铁矿浆过滤回水管道结垢物形成的化学反应机制。

The scale was accumulated in the backwater pipe of iron ore slurry filtration,when the sulfuric acid was replaced by R31 filter aid for filtrating iron ore slurry in a domestic beneficiation plant.In order to reveal the chemical reaction mechanism of scale formation,the mineral phase of scale was confirmed to be calcium carbonate by X-ray diffraction analysis.The fluorescence analysis method was used to quantitatively analyze the elemental composition of different filtrates.The simulation experiment of calcium carbonate formation was investigated.The results show that the CO3^2- reacted with Ca^2+to generate the CaCO3 precipitate after mixing the R31 filtrate with sulfuric acid filtrate.The CO3^2- was produced by the dissolution of CO2 in water,and the CO2 was formed from decarboxylation of carboxyl(-COOH)in the filter of R31 filter aid in alkaline solution.The Ca^2+ions were formed by the reaction of sulfuric acid and calcium-bearing mineral in iron concentrate during filtration process.Finally,the chemical reaction mechanism of the scale formation in backwater pipe of iron ore slurry filtration was revealed.