| Caking of sulfide ores is a long-standing and difficult problem in mining and processing of sulfide deposits. It has been regarded as the major security risk of sulfide minerals enterprise for a long time. The research on caking factors and caking detection technology can provide basis for the development of caking preventive measures to reduce losses caused by agglomeration.Based on the collection and access to relevant literature, systematic review was given to the agglomerates mechanisms at home and abroad, caking detection technology, spontaneous combustion characteristics of sulfide ores. The caking factors of sulfide ores were analyzed by the combination of theoretical analysis, experimental method and numerical analysis, and a new detection method was found as well as caking characteristics of preventive measures made. The main research contents and results in this paper are as follows:(1) Various caking factors of the sulfide ores were analyzed qualitatively through the establishment of FTA, and the minimal cut (path) sets which could get combination of various caking factors, were obtained by using logical operators and Boolean algebra simplification of rules. According to the approximation determination of their important degree structure, main factors were initially identified by order. Based on this, a comprehensive caking mechanism was divided into three categories: solubility mechanism, chemical reaction theory and physical mechanism.(2) Characterization method was introduced to describe the caking situation from the previous qualitative observation to quantitative evaluation. In addition to the oxidation weighting law and the caking rate, a modified uniaxial testing method (COSTT) was proposed to analyze caking characteristics by multi-angle way. It can not only determine the yield strength, but also can measure more other mechanical parameters in the project such as the materials ultimate strength, strain and so on. Compared with other methods, COSTT would be more intuitive and accurate, and can also be coupled analysis with various factors, providing a technical reference for anti-caking agents in the future. (3) Single factor experiments and orthogonal test were combined to analyze the temperature, humidity, water content and particle size qualitatively, and get their order as follows:temperature> water content> humidity> particle size. Experimental results show that changing these factors can significantly change the caking situation of the sulfide ores.(4) Based on the results of single factor experiments and orthogonal test, response surface method was used to make regression analysis on the experimental data, and gain the regression equation among caking factors including temperature, water content, humidity and particle size. Y=93.654+14.048X1,+3.125X2+0.910X3+14641X4-4.724X1X2-8.663X1X3 +2.660X1X4-35.655-28.867x22-0.913X1X3+1.601X2X4-19.156X23 +0.042X3X4-1.158X24R2=0.881,In the equation, X1,X2,X3,X4 respectively represent the level value of temperature, water content, humidity and particle size, not the specific values. The expression shows that the effect of various factors on caking rate is not a simply single relationship, but the second relationship, and coefficients of X1X4 and X2X4 are larger, so the interactions between temperature and water content, humidity and water content are obvious, but the others not significant.(5) In the paper, it proposed several measures to prevent the caking of sulfide ores:physical, chemical and technology law, and then put forward some suggestions on the management level. |
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