The Brazilian dolomitic itabirites are considered marginal resources and deposited in waste rock dumps as the cationic reverse flotation circuits present limitations to remove carbonate minerals. This work proposes the synthesis and application of N,N-bis(2-hydroxyethyl)oleamide as a collector in the flotation of carbonates present in dolomitic itabirites. Hematite, quartz, calcite, and dolomite samples were characterized by XRPD and XRF, indicating high purity. The novel collector was characterized by NMR, ATR-FTIR, zeta potential and surface tension measurements, whereas its selectivity was evaluated in microflotation tests, and adsorption was studied via zeta potential and ATR-FTIR. The collector showed maximum selectivity in alkaline condition (pH 10) at 50 mg/L, at which only dolomite and calcite were recovered at 74.7 % and 78.1 %, respectively. The adsorption studies were performed at pH 10, showing that the collector adsorbs non-specifically onto dolomite and calcite, but not quartz and hematite, which is consistent with the flotation results. Microflotation tests with a mixed mineral sample in the presence of corn starch confirmed its potential to depress the carbonate minerals, requiring conditioning with collector to take place prior to the addition of depressant. This approach, followed by conditioning with etheramine showed potential to separate dolomite, calcite, and quartz from hematite.

中文翻译：

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白云石铁矿石中碳酸盐浮选：新型 N，N-双（2-羟乙基）油酰胺捕收剂的合成、表征和应用


巴西白云石 itabirites 被认为是边缘资源，并沉积在废石堆中，因为阳离子反向浮选回路对去除碳酸盐矿物存在限制。本工作提出了 N，N-双（2-羟乙基）油酰胺的合成和应用，作为捕收剂在白云石意大利铁矿中存在的碳酸盐浮选中的应用。通过 XRPD 和 XRF 对赤铁矿、石英、方解石和白云石样品进行了表征，表明纯度高。通过 NMR、ATR-FTIR、zeta 电位和表面张力测量对新型捕收剂进行表征，同时在微浮选试验中评价其选择性，并通过 zeta 电位和 ATR-FTIR 研究吸附。捕收剂在碱性条件 （pH 10） 下表现出最大的选择性，为 50 mg/L，其中只有白云石和方解石的回收率分别为 74.7% 和 78.1%。在 pH 值为 10 的情况下进行吸附研究，表明捕收剂非特异性吸附到白云石和方解石上，而不是石英和赤铁矿上，这与浮选结果一致。在玉米淀粉存在下使用混合矿物样品进行的微浮选测试证实了其抑制碳酸盐矿物的潜力，需要在添加抑制剂之前使用捕收剂进行调节。这种方法，然后用乙醚胺进行调节，显示出从赤铁矿中分离白云石、方解石和石英的潜力。