铁矿浆过滤回水管道结垢物形成机制

摘要：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，CO2-3与Ca2+反应生成CaCO3沉淀。CO2-3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CO2-3；Ca2+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Ca2+。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。

Formation mechanism of scale in iron ore slurry filtration backwater pipe

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 CO2-3 reacted with Ca2+ to generate the CaCO3 precipitate after mixing the R31 filtrate with sulfuric acid filtrate. The CO2-3 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 Ca2+ 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.