Optimized molecular length and uniform molecular weight distribution enhance depression effect of macromolecular depressant towards serpentine

IF 5 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering Pub Date : 2025-10-21 DOI:10.1016/j.mineng.2025.109842

Jian Cao , Lingxiao Gao , Wei Sun , Zhiyong Gao , Bingang Lu , Xiaohui Su , Chunhua Luo , Xiangan Peng , Fengxiang Yin

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引用次数: 0

Abstract

Nickel is an extremely important strategic metal resource. However, in the flotation of nickel sulfide ores, serpentine causes a decline in the grade of nickel concentrate due to heterocoagulation and mechanical entrainment. Organic polymers represent prevalent depressant choices for serpentine. Typical synthetic polymer depressants are usually prepared via conventional free radical polymerization, but synthesized depressants exhibit significant defects: broad molecular weight distribution and uncontrollable molecular structure, which markedly reduce the depression effectiveness. To address these challenges, this study proposes, for the first time, the use of reversible addition-fragmentation chain transfer (RAFT) polymerization to precisely design and synthesize an ABA-type triblock copolymer depressant from acrylamide and acrylic acid. Through systematic comparison with a random copolymer of acrylamide and acrylic acid (RAB) prepared via traditional free radical polymerization, the innovative advantages and mechanisms of the ABA-type depressant in terms of molecular structure, adsorption behavior and flotation performance were elucidated. Experimental results demonstrate that, owing to narrow molecular weight distribution and long molecular chains, ABA forms a dense adsorption layer on the serpentine surface. Through chelation of carboxyl groups with Mg²⁺ and hydrogen bonding, ABA significantly enhances surface hydrophilicity and reverses the surface charge of the serpentine, effectively inhibiting heterocoagulation between serpentine and pentlandite and increasing the macroscopic size of fine serpentine particles. This study provides a novel strategy for the design of high-performance macromolecular depressants targeting magnesium silicate gangue in complex nickel ore flotation, overcoming the technical limitations of traditional depressants and demonstrating significant industrial application value.

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优化的分子长度和均匀的分子量分布增强了大分子抑制剂对蛇纹石的抑制效果

镍是极为重要的战略金属资源。但在硫化镍矿石浮选过程中，蛇纹石由于异混和机械夹带作用，使镍精矿品位下降。有机聚合物是蛇纹石常用的抑制剂。典型的合成聚合物抑制剂通常采用传统的自由基聚合法制得，但合成的抑制剂存在分子量分布广、分子结构不可控等缺陷，显著降低了聚合物的抑制效果。为了解决这些挑战，本研究首次提出利用可逆加成-破碎链转移（RAFT）聚合技术，以丙烯酰胺和丙烯酸为原料，精确设计和合成aba型三嵌段共聚物抑制剂。通过与传统自由基聚合法制备的丙烯酰胺-丙烯酸无规共聚物（RAB）进行系统比较，阐明了aba型抑制剂在分子结构、吸附行为和浮选性能等方面的创新优势及其机理。实验结果表明，ABA由于分子量分布窄，分子链长，在蛇纹石表面形成致密的吸附层。ABA通过羧基与Mg2+和氢键的螯合作用，显著增强了蛇纹石的表面亲水性，逆转了蛇纹石的表面电荷，有效抑制了蛇纹石与pentanite之间的异聚，增加了蛇纹石细颗粒的宏观尺寸。本研究为复杂镍矿浮选中硅酸镁脉石型高性能高分子抑制剂的设计提供了新思路，克服了传统抑制剂的技术局限，具有重要的工业应用价值。

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来源期刊

Minerals Engineering 工程技术-工程：化工

CiteScore

8.70

自引率

18.80%

发文量

519

审稿时长

81 days

期刊介绍： The purpose of the journal is to provide for the rapid publication of topical papers featuring the latest developments in the allied fields of mineral processing and extractive metallurgy. Its wide ranging coverage of research and practical (operating) topics includes physical separation methods, such as comminution, flotation concentration and dewatering, chemical methods such as bio-, hydro-, and electro-metallurgy, analytical techniques, process control, simulation and instrumentation, and mineralogical aspects of processing. Environmental issues, particularly those pertaining to sustainable development, will also be strongly covered.