基于特征级融合与XGBoost的煤泥浮选指标多源信息预测研究

multi−source information prediction of coal slime flotation index based on feature level fusion and XGBoost

  • 摘要: 煤泥浮选是选煤过程中的关键环节,其浮选指标(产率、灰分及可燃体回收率)的准确预测对于优化工艺参数、稳定产品质量及提升生产效益具有重要意义。然而,浮选过程具有多变量耦合、强非线性及信息表征不充分等特点,单一信息源难以全面刻画其动态变化规律,从而制约了预测模型精度的进一步提升。针对上述问题,本文提出一种基于特征级融合与XGBoost的煤泥浮选指标多源信息预测方法。首先,基于工业相机采集浮选泡沫图像,利用分水岭算法实现泡沫区域分割,并提取平均泡径、泡径标准差、泡沫数量、圆度等结构特征以及基于灰度共生矩阵的纹理特征,构建泡沫视觉特征体系。随后,将泡沫视觉特征与搅拌转速、吸气量及药剂制度等6类关键工艺参数进行融合,通过特征级融合方法实现多源数据的统一表征,构建多源信息特征向量。在此基础上,利用XGBoost建立浮选指标预测模型,以刻画多源信息与浮选指标之间的非线性映射关系。实验结果表明,融合模型的预测性能显著优于单一信息源模型,其决定系数R2达到0.96,均方根误差(RMSE)降至1.26。特征重要性分析结果显示,捕收剂用量、吸气量及泡沫泡径对预测结果影响显著。研究结果为浮选过程的智能化监测与优化控制提供了可靠的数据支撑与建模思路。

     

    Abstract: Fine coal flotation is a critical operation in coal preparation, and the accurate prediction of flotation performance indices is essential for process parameter optimization, product quality stabilization, and production efficiency improvement. However, the flotation process is characterized by multivariable coupling, strong nonlinearity, and insufficient state representation, making it difficult for a single information source to comprehensively describe variations in flotation conditions. To address these issues, a multisource information−based prediction method integrating feature−level fusion and extreme gradient boosting (XGBoost) was proposed. First, flotation froth images were acquired using an industrial camera and subjected to grayscale conversion, noise reduction, and watershed segmentation. Structural features, including the mean bubble diameter, standard deviation of bubble diameter, bubble count, mean bubble area, and circularity, were extracted. Texture features, including contrast, energy, entropy, and homogeneity, were subsequently calculated from the gray−level co−occurrence matrix. The extracted visual features were then integrated with six key operating variables, namely impeller speed, air flow rate, feed flow rate, feed concentration, collector dosage, and frother dosage, through feature−level concatenation. A unified multisource feature vector was thereby constructed. An XGBoost−based model was subsequently developed to characterize the nonlinear relationships between the multisource information and the flotation performance indices. Furthermore, low−contribution variables were eliminated according to feature importance, and the fused feature space was reconstructed to reduce information redundancy and improve model generalization. The experimental results showed that, after feature selection, the coefficients of determination (R2) for the prediction of flotation yield, clean coal ash content, and combustible recovery reached 0.631, 0.562, and 0.956, respectively, while the corresponding root mean square errors (RMSEs) were 1.09, 0.86, and 1.26. The highest prediction performance was obtained for combustible recovery. Feature importance analysis indicated that collector dosage, air flow rate, mean bubble diameter, and froth circularity were the principal variables affecting the prediction results. The proposed method enables the complementary representation of froth morphology and operating conditions and provides a practical modeling approach for online state perception, soft−sensor development, and process optimization in fine coal flotation.

     

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