金鸡滩煤矿是陕北榆神矿区主力矿井之一，年产煤炭1700万t，煤炭开发过程中产生的固体废弃物——煤矸石100余万t/a，对煤矸石加以综合利用是实现区域煤炭资源绿色、低碳、清洁、高效利用的重要组成部分。本文以该区煤矸石为对象，运用现代分析测试技术对其基本性质进行了深入分析，通过Na₂CO₃煅烧活化-HCl酸浸去杂过程对煤矸石进行预处理，富集煤矸石中的硅元素制备出了性能优异的超细硅酸铝，对矸石提硅后残余的铝、铁元素制备了聚合氯化铝铁（PAFC），本研究旨在开辟区域煤矸石高值化利用新途径。

金鸡滩煤矸石灰分为70.59%，属于中灰煤矸石，主要矿物组成为石英、高岭石、方解石、伊利石和黄铁矿等。其灰成分主要由SiO₂(53.61%)、Al₂O₃(23.25%)、Fe₂O₃(6.43%)组成，具有制备超细硅酸铝和PAFC的物质基础。

采用“Na₂CO₃煅烧活化-HCl酸浸”工艺对煤矸石进行提硅除杂预处理。煤矸石经Na₂CO₃煅烧后，石英和高岭石基本消失，生成了霞石和钠长石，黄铁矿转化为活性更高的偏铁酸钠；煅烧活化后的煤矸石在HCl酸浸后铝、铁等杂质浸出效果显著。研究表明：Na₂CO₃含量和酸浸时间是影响Al₂O₃、Fe₂O₃浸出率的主要因素；最佳浸出条件为：Na₂CO₃含量40%、煅烧温度850℃、煅烧时间2 h、HCl浓度6 mol/L、液固比15 mL/g、酸浸时间60 min，此条件下Al₂O₃、Fe₂O₃的浸出率分别为98.97%、99.03%，酸浸滤渣中SiO₂含量为98.18%。

将酸浸滤渣与NaOH溶液水热反应制备水玻璃，结果表明NaOH浓度和液固比是影响水玻璃制备的主要因素。水玻璃最佳制备条件为：NaOH浓度为8%、液固比为10 mL/g、碱浸时间50 min，此条件下制备的水玻璃中SiO₃^2-浓度为0.39 mol/L，SiO₂浸出率为95.21%。将水玻璃与Al₂(SO₄)₃反应制备超细硅酸铝，结果显示n(Si)/n(Al)为5时，合成的超细硅酸铝符合企业标准，所制备的超细硅酸铝平均粒径为531.17 nm，但粒径分布不太均匀，颗粒有一定团聚结块现象。

采用十二烷基苯磺酸钠（SDBS）、吐温-80（Tween-80）和硅烷偶联剂（KH-560）三种表面活性剂对超细硅酸铝改性。结果显示：KH-560改性效果最佳，其平均粒径从改性前的531.17 nm降至295.31 nm，且粒径分布均匀；SDBS和Tween-80改性后平均粒径分别为461.92 nm和396.06 nm，分散效果较差。FTIR分析表明，KH-560通过硅羟基与颗粒表面形成稳定的Si-O-Si化学键，而SDBS和Tween-80通过氢键或物理吸附作用于颗粒表面；这种机理差异直接影响超细硅酸铝的热稳定性，KH-560改性样品高温残留量（92.20%）接近未改性样品（92.59%），优于SDBS（90.85%）和Tween-80（91.47%），说明KH-560改性可有效维持材料高温结构稳定性。SEM分析直观揭示了不同改性剂对颗粒形貌的调控作用，KH-560改性样品呈现均匀分散的球形颗粒，而SDBS和Tween-80改性样品显示有部分颗粒软团聚。KH-560改性优化了超细硅酸铝的分散性、热稳定性及微观结构，为高性能复合材料开发提供理论支撑。

以酸浸滤液为原料制备PAFC，结果显示n(Al)/n(Fe)是影响PAFC制备的关键因素。PAFC最佳制备条件为：n(Al)/n(Fe)为9、pH值为3、聚合时间为2.5 h、聚合温度为90℃，此条件下制备的PAFC对400度污水的浊度去除率为85.57%。实验模拟PAFC处理煤泥水的实际效果表明，自制PAFC对2 g/L煤泥水絮凝效果优于市售PAFC；当煤泥水pH值为6~8时，絮凝效果最好；pH值为7时，自制PAFC投加量为300 mg/L对2 g/L煤泥水最大浊度去除率为85.65%。FTIR分析显示自制PAFC有明显的Fe-O-Fe、Al-O-Al的振动吸收峰，表明自制PAFC中金属离子得到有效聚合。

Jinjitan Coal Mine, a key production site in the Yushen mining area of northern Shaanxi, produces 17 million tons of coal annually while generating over 1 million t/a of coal gangue solid waste. Comprehensive utilization of coal gangue is crucial for achieving green, low-carbon, clean, and efficient regional coal resource utilization. This study focuses on coal gangue from this region, employing modern analytical techniques to systematically characterize its properties. A pretreatment process involving Na₂CO₃ calcination-activation followed by HCl acid leaching was developed to remove impurities and enrich silicon, enabling the synthesis of high-purity ultrafine aluminosilicate. Residual aluminum and iron from the silicon extraction process were co-utilized to produce polyaluminum ferric chloride (PAFC), establishing a novel pathway for high-value, integrated utilization of coal gangue.

The ash content of Jinjitan coal gangue is 70.59%, classifying it as high-ash coal gangue. The primary mineral composition includes quartz, kaolinite, calcite, illite, and pyrite. The ash components are predominantly composed of SiO₂ (53.61%), Al₂O₃ (23.25%), and Fe₂O₃ (6.43%), providing a material basis for the preparation of ultrafine aluminum silicate and co-production of PAFC.

The process of "Na₂CO₃ calcination activation -HCl acid leaching" was used to extract silicon and remove impurities from coal gangue. After calcination of coal gangue with Na₂CO₃, quartz and kaolinite disappeared, forming nepheline and albite, while pyrite transformed into more reactive sodium metafebrite. The leaching of impurities such as aluminum and iron was significantly improved after HCl acid leaching of the calcined and activated coal gangue. The study demonstrates that the Na₂CO₃ content and acid leaching time are the key factors influencing the leaching rates of Al₂O₃ and Fe₂O₃. The optimal leaching conditions are: Na₂CO₃ content of 40%, calcination temperature of 850°C, calcination time of 2 h, HCl concentration of 6 mol/L, liquid-to-solid ratio of 15 mL/g, and acid leaching time of 60 min. Under these conditions, the leaching rates of Al₂O₃ and Fe₂O₃ are 98.97% and 99.03%, respectively, and the SiO₂ content in the acid leaching residue is 98.18%.

The hydrothermal reaction of the acid leaching residue with NaOH solution to prepare water glass revealed that the NaOH concentration and liquid-to-solid ratio are the main factors affecting the preparation of water glass. The optimal preparation conditions for water glass are: NaOH concentration of 8%, liquid-to-solid ratio of 10 mL/g, and alkali leaching time of 50 min. Under these conditions, the concentration of SiO₃^2- in the prepared water glass is 0.39 mol/L, and the SiO₂ leaching rate is 95.21%. The reaction of water glass with Al₂(SO₄)₃ to prepare ultrafine aluminum silicate found that when n(Si)/n(Al) is 5, the synthesized ultrafine aluminum silicate meets the enterprise standards. The average particle size of the prepared ultrafine aluminum silicate is 531.17 nm, but the particle size distribution is non-uniform, with significant agglomeration.

Three surfactants—sodium dodecylbenzene sulfonate(SDBS), Tween-80, and silane coupling agent (KH-560)—were used to modify the ultrafine aluminum silicate. The results show that KH-560 exhibits the best modification effect, with its average particle size decreasing from 531.17 nm before modification to 295.31 nm, and the particle size distribution uniformity is optimal. The particle sizes after SDBS and Tween-80 modification are 461.92 nm and 396.06 nm, respectively, with poorer dispersion. FTIR analysis shows that KH-560 forms a stable Si-O-Si chemical bond with the particle surface through silanol groups, while SDBS and Tween-80 interact with the particle surface through hydrogen bonding or physical adsorption. This difference in mechanism directly affects the thermal stability of the ultrafine aluminum silicate. The high-temperature residue (92.20 %) of the KH-560 modified sample is close to that of the unmodified sample (92.59%), which is significantly better than SDBS (90.85%) and Tween-80 (91.47%), indicating that KH-560 modification can effectively maintain the high-temperature structural stability of the material. SEM analysis visually reveals the regulatory effect of different modifiers on particle morphology. The KH-560 modified sample presents uniformly dispersed spherical particles, while the SDBS and Tween-80 modified samples exhibit some particle soft agglomeration. KH-560 modification optimizes the dispersibility, thermal stability, and microstructure of ultrafine aluminum silicate, providing a theoretical basis for the development of high-performance composite materials.

Using acid leaching filtrate as a raw material to prepare PAFC, the study found that n(Al)/n(Fe) is a key factor affecting PAFC preparation. The optimal preparation conditions for PAFC are: n(Al)/n(Fe) of 9, pH of 3, polymerization time of 2.5 h, and polymerization temperature of 90°C. Under these conditions, the turbidity removal rate of the prepared PAFC for simulated wastewater (400 NTU) is 85.57%. Laboratory simulation of the actual effect of PAFC on treating coal slurry water revealed that the flocculation performance of the in-house synthesized PAFC on 2 g/L coal slurry water is superior to that of commercially available PAFC. Achieving the same flocculation effect requires a lower dosage of the in-house synthesized PAFC. When the pH of the coal slurry water sample is between 6 and 8, the treatment effect is optimal. At pH=7, the maximum turbidity removal rate of 85.65% is achieved with an in-house synthesized PAFC dosage of 300 mg/L for 2 g/L coal slurry water. FTIR analysis revealed that the in-house synthesized PAFC exhibits distinct vibrational absorption peaks corresponding to Fe-O-Fe and Al-O-Al, indicating effective polymerization of metal ions within the PAFC.

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