Model Experimental Study On Maldistribution In The Feeding Part Of Copper Flash Furnace

Flash smelting technology is an advanced modern technology of copper smelting and paid more and more attention by copper smelting industries. The concentration distribution in the shaft takes a great role in metallurgical transport process. Uniform distribution of concetration is a precondition to ensure a smooth operation and high efficiency for the flash smelting furnace. To take a real feeding part of copper flash smelting furnace as the prototype, the uniform degree of particle distribution in the feeding part is studied by a lot of model experiments.For the convience of analysis and comparison for the maldistribution rule of the feeding part, the particle maldistribution phenomen is defined and classifid. The expressions of maldistribution function-mass maldistribution function and size maldistribution function-are determined, which are used to quantatively describe the maldistribution degree. Based on the assumptions of pseudo fluid, the main factors that affect maldistribution are obtained by analyzing the motion of particle material in slide tube and distributor channel.According to the similarity principle, the experimental unit with the similarity propotion of 1:4 was designed and made. The related measuring system was developed. Quartz sand, white quartz sand and concentrate power were applied to model particle material in the feeding part. The experimental data were treated with Matlab and Excell software. The main following results are obtained from the experimental results in the case of tangential feeding pattern. (1) There are obvious local maldistribution, circumferential maldistribution and radical maldistribution. (2) With the increase of feeding mass rate, circumferential maldistribution and local maldistribution grow, but radical maldistribution change little. (3) The maldistribution degree when feeding away from the center is higher than that when feeding near the center. (4) Circumferential maldistribution of concentrate power is more serious than that of quartz sand and white quartz sand. (5) Size maldistribution phenomen does not take place. To improve the uniform of particle material distribution, some optimal schemes for the feeding part are provided from changing feeding direction, flowing area and flowing direction. Four schemes, i.e. some baffles being set on the slide tube along two different directions and on the interval board, as well as a cross-feeding pattern, were tried. The results show that two baffles on the slide tube and cross-feeding can decrease maldistribution degree, but the former is difficult to be realized for the real system. So cross-feeding is thought to be appropriate. A lot of model experimental results for the cross-feeding pattern indicate that, comparied to the tangential feeding pattern, both the local and circumferential maldistribution for the cross-feeding are greatly lowered when the feeding mass rate increase.To discuss the importance of influence factors on particle material maldistributino of feeding part, their correlation degree was analyzed by means of grey correlation theory. The results showed that, the descend order of correlation degree is the angle between slide tube and interval board of distributor, the feeding mass rate, model unit height, partile density, the angle of slide tube, cross section ratio of slide tube, the ring slit width of the distributor and the width of slide tube at entrance.