| This paper reviewed the phosphate rock resources all over the world, explained the urgent necessity of development of the phosphate rock in low grade and more impurities, especially in the comprehensive utilization of the middle-low grade phosphate rock, such as collophane ore in Yunnan province. The paper also systematically discussed the flotation of phosphate rock and its application and effect at home and abroad, pointed out the importance of the collophane ore processing by means of flotation column.Based on introduction of the main structure and working principle about CPT flotation column & FCSMC flotation column, combined with the characteristics of the two separation system in the course of the collophane ore processing, analyzed the effects of the technology parameters on separation indexes, laid a theoretical foundation for experiments design of column flotation about the middle-low grade collophane ore.Through summarization of the bubble mineralization mechanism, through quantitative analysis of the bubble size, the bubble buoyancy velocity and the bubble surface area flux when the collophane ore can be processed by CPT flotation column, the paper came to the conclusion:while determining the aeration volume, reducing the bubble size and increasing the bubble surface area flux, the adaptability of the mineral particles size can be increased, which provided a theoretical basis for improving the P2O5 recovery rate.In the basis of the kinetic theory of column flotation, the paper verified the rationality of the flotation rate equation by derivation of separation variables integral, analyzed the fitting degree between the theoretical calculating results of column flotation rate model K=ε/(ε∞-ε)·τand the laboratory test results of collophane ore processing, proved the flotation column separation system and the experimental design used scientific, rational.CPT flotation column operating parameters can be optimized through the quantitative analysis of affected factors of the column flotation. The laboratory test results showed that the P2O5 recovery rate was 85.63%, the collophane concentrate grade was 30.23%, the MgO content was 0.87%, when the aeration volume was 3.56sl/min, the feeding amount was 343ml/min, the wash water flow was 68ml/min, the ore grade was 23.25%, which met the specific requirements of the three indexes.According to semi-industrial test data of FCSMC flotation column, using regression analysis, the paper established a mathematical model about the collophane ore column effective and valuable in the light of the fit between the model's theoretical analysis data and the semi-industrial experiment data.The regulated tailings flow volume was 10.30-14.86cm3/s by means of the calculation of bias about column flotation in order to ensure the normal operation of the collophane ore processing. Under the positive bias condition, when a effective volume of 9.725 liters CPT flotation column with 3 inch in diameter and 10 feet in length can be used to process the collophane ore, if the floating bubble average velocity was more than 3.62cm/s, then the bubble size increased, the bubble load capacity and the foam stability decreased the at the same time, which resulted in lowering the P2O5 recovery rate. If the floating bubble average velocity was less than 3.62cm/s, then the bubble size decreased, the small bubbles will sink or suspend in the slurry if they overloaded, which also lowered the P2O5 recovery rate.In the column flotation process, if the flotation column was too high, the bubble will reduce the load capacity, the probability of the mineral particles off the mineralized bubble surface will increase. Based on the optimization parameters of the collophane ore column flotation, the paper calculated that the residence time range of the floating mineral wasτ≥266-385s≈4.43-6.42 min, the collection zone height range of the flotation column was H≈125-180cm, in order to determine the size of the flotation column with different height to meet the requirement of separation indexes. Considering the height range, the height of flotation column was higher for minerals that were difficult to float. The height of flotation column was lower for minerals that were easy to float.In view of the three aspects:the column flotation rate constant K=1.828 min-1, the mineral average residence timeτp≈299 s≈5 min, the slurry flow state (peclet criterion Pe≈1.523:incomplete mixing flow state), the paper gave the theoretical calculated result of CPT collophane ore processing, that was, the P2O5 recovery rate was 89.02%, which was larger than the P2O5 recovery rate 85.63% obtained from the optimal test data. If the theoretical calculated value was 85.63%, then the actually maximum P2O5 recovery rate was less than 91.38% without including other affected factors.The paper analyzed the relationship among the P2O5 recovery rate, the collophane concentrate grade and the column flotation rate constant K. When the average residence time was fixed, the column flotation rate constant K increases with the increasing aeration volume, indicating the higher P2O5 recovery rate but the lower collophane concentrate grade. The column flotation rate constant K decreases with the increasing feeding amount and the wash water flow, indicating the higher collophane concentrate grade but lower P2O5 recovery rate. To sum up, the recovery rate of column flotation depended on three factors:the column flotation rate constant K, the residence time of the floating mineral in the flotation column and the pulp mixed state of column flotation.This paper provided a scientific theory basis for meeting the specific requirement of separation indexes of column flotation about the middle-low grade collophane ore in Yunnan province.
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