Recovering fine valuable material has been a significant challenge in minerals processing. This primarily stems from insufficient collision opportunities between fine particles and bubbles, specifically when utilising traditional recovery methods such as froth flotation. This research endeavours to address this challenge by exploring the use of various commercially available, high molecular weight polymers- specifically polyacrylamide (PAM)- to selectively aggregate hematite from quartz. Investigation of the conditions in which selective aggregation of hematite over quartz occurs, with the goal to achieve aggregate sizes of between 20 and 150 μm, were undertaken. Targeting this size range ensure that conditions are optimised for future use in conventional mechanical flotation cells as an efficient mineral recovery method. The study investigates the selectivity of charged PAM towards hematite and quartz at pH 10, using adsorption studies. Anionic PAM demonstrates a preference for hematite, with a range of charge density studies, highlighting stronger adsorption capacity with lower charge density polymers. Using BlazeMetrics probe technology for in-situ sizing and imaging, it was observed that conditioning 50–300 g APAM per t of hematite resulted in aggregates in the range of 30–230 μm after 5 min. Interestingly, the charge density of APAM does not markedly affect the size of the hematite aggregates, although altering the charge density of the polymer impacts the selectivity towards quartz. Additionally, cationic PAM results in the simultaneous aggregation of both hematite and quartz, not demonstrating selectivity. To mitigate heterocoagulation between minerals, a common dispersant, sodium hexametaphosphate (SHMP), was employed, which notably prevents quartz aggregation. Separation of aggregated hematite from quartz by sedimentation was only slightly effective with the majority of quartz settling with the hematite. Adding up to 1000 g of dispersant per t of hematite reduced the amount of quartz in the sediment bed by 23 %. The dispersant increased the magnitude of the negative zeta potential of the two minerals, particularly hematite, lowering heterocoagulation and improving effectiveness of hematite flocculation.

中文翻译：

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使用带电聚丙烯酰胺选择性聚集石英中的赤铁矿：原位分级


回收优质有价值的材料一直是矿物加工中的重大挑战。这主要是由于细颗粒和气泡之间的碰撞机会不足，特别是在使用泡沫浮选等传统回收方法时。本研究致力于通过探索使用各种市售高分子量聚合物（特别是聚丙烯酰胺 (PAM)）选择性地聚集石英中的赤铁矿来应对这一挑战。研究了赤铁矿在石英上发生选择性聚集的条件，目标是实现 20 至 150 μm 之间的聚集体尺寸。针对此尺寸范围可确保优化条件，以便将来在传统机械浮选槽中作为有效的矿物回收方法使用。该研究通过吸附研究研究了 pH 10 时带电 PAM 对赤铁矿和石英的选择性。阴离子 PAM 表现出对赤铁矿的偏好，通过一系列电荷密度研究，强调了较低电荷密度聚合物具有更强的吸附能力。使用 BlazeMetrics 探针技术进行原位尺寸测定和成像，观察到每吨赤铁矿使用 50-300 g APAM 进行调节 5 分钟后会产生 30-230 μm 范围内的聚集体。有趣的是，尽管改变聚合物的电荷密度会影响对石英的选择性，但 APAM 的电荷密度不会显着影响赤铁矿聚集体的尺寸。此外，阳离子 PAM 导致赤铁矿和石英同时聚集，未表现出选择性。为了减轻矿物之间的异凝聚，使用了一种常见的分散剂六偏磷酸钠（SHMP），它可以显着防止石英聚集。 通过沉降从石英中分离聚集的赤铁矿仅稍微有效，因为大多数石英与赤铁矿一起沉降。每吨赤铁矿添加多达 1000 克分散剂，可使沉积床中的石英含量减少 23%。分散剂增加了两种矿物（特别是赤铁矿）的负 zeta 电位的大小，降低了异混凝并提高了赤铁矿絮凝的效果。