【作者】 曾克文；

【导师】 余永富； 薛玉兰；

【作者基本信息】 中南大学 ， 矿物加工工程， 2001， 博士

【摘要】 包钢选厂在弱磁-强磁-浮选流程工业分流试验初期，从磁选铁精矿中反浮选萤石的精选作业曾出现泡沫大，并且基本不被矿化，反浮作业无法正常运行的现象，同样出现类似现象的还有一水硬铝石、胶磷矿等氧化矿浮选，只不过不象前者严重而已。出现这种现象是当前我国工业浮选生产中比较普遍的的现象，只是程度不同，不太引起人们重视和注意。为查明出现此现象的原因，并提出解决的方法，论文主要结合包钢选矿厂磁选铁精矿反浮选脱氟萤石泡沫精选过程和河南铝土矿正浮选过程，对浮选动力学有关问题开展了较深入的研究。 1．萤石、赤铁矿单矿物进行单泡浮选管的矿粒粒度、充气量、气泡大小及药剂等对浮选影响的试验，试验表明，萤石浮选回收率随矿粒粒度增大而增大，随充气量、搅拌强度的增加而增加，随气泡尺寸的减小而增加，萤石在很低的搅拌作用或仅靠毛细压力产生的气泡即能上浮，属于易浮矿石。通过对萤石泡沫吸附状念的照相发现萤石是呈多颗粒吸附在气泡的底部。 2．运用粒子动态分析仪(PDA)对XFD-12型8L(立升)浮选机槽内粒子进行速度分布测量，发现在整个槽中沿径向的切向时均速度是由正变负，零点出现在轴心与槽壁中间，此处开始出现回流(backward flow)，回流的剪切作用对矿粒产生脱落作用。 沿径向混合区的轴向时均速度逐渐上升，有利于槽壁附近的矿粒悬浮，分离区、泡沫区的轴向时均速度是先增后减，对轴心附近的矿粒悬浮能力较大，对远离轴心的矿粒悬浮能力降低。轴向脉动速度沿径向逐渐下降，对已矿化矿粒的脱附能力由大变小。 转速增大，紊流强度增大，对轴心附近未矿化矿粒的悬浮能力和已矿化矿粒的脱附能力都相应增大。 3．对矿粒在水中的受力状态进行分析，运用紊流条件下矿粒最大稳定粒度计算公式，对12L(立升)浮选机中强磁铁精矿反浮选脱氟精矿精选过程进行了计算，当叶轮雷诺数从0.16×10~6增加至0.7×10~6时，萤石最大浮选粒度从0.134mm下降至0.059mm。实际矿石浮选萤石泡沫精矿筛析结果表明，当叶轮雷诺数从0.32×10~6增至0.7×10~6时，+0.074mm粒级含量极少，+0.054mm粒级含量从9.25％下降至4.58％，-0.054mm+0.038mm粒度含量由13.68％降至8.3％。汁算数据与实际矿石筛析结果都表明，紊流强度增大，泡沫中粗粒级含量减小。 4．用PDA在XFD-12型8L浮选机中测定的速度值，进行混合区、分离区、泡沫区紊流运动功率谱计算，得紊流脉动频率，混合区小于20Hz，分离区在20-30Hz之间，泡沫区在25-35Hz之间，浮选槽内紊流脉动以低频为主，且紊流脉动动能是混合区大于分离区大于泡沫区。紊流脉动动能大，矿粒运动动能大，在混合区易与中南人‘学博行学位沦文摘要气泡发生碰才童粘附，但在分离区、泡沫区会引起矿粒从气泡上脱落。 5.研究了矿浆紊流强度(口一卜轮雷诺数)，在12L浮选机中对实际矿石浮选的彩响。用包钢选厂一强磁铁精句“，进行反浮选脱氟精选过程的紊流强度对浮选影响!，]{J试验，结果表明，当紊流强度较低时，随紊流强度增加，萤石泡沫精矿的产率、「，!收率逐渐增加，当紊流强度达到0.32 xlo“时，浮选指标最佳，紊流强度}时帅加，萤石品位和回收率都下降，降低了反浮选脱氟效果。用郑州中州铝厂一铝上佃”进行正浮选过程紊流强度对浮选影响的试验，结果类似萤石浮选，浮选最佳值出现在中等紊流强度(). 29 Xl护。实际矿石浮选试验表明，紊流强度过大对浮选不利，特别对粗粒浮选不利。 6.紊流对浮选有双重作用，紊流强度低时，有利于泡沫稳定，矿粒不易从气泡土脱落，但太低，不利于矿粒与气泡发生碰撞粘附和矿粒悬浮。紊流强度高时，有利一于矿粒与气泡发生碰撞粘附和矿粒悬浮，但太高，易造成矿粒从气泡f:脱附，所以选取最佳的紊流条件是浮选的关键。根据运动相似原理，首次使用悬浮状态判据(N·D·D/L=常数)作为根据小型浮选机试验操作条件推算大型浮选机理想操作条件的判据，此判据简一单易操作，对工业生产有指导作用。 7.用12L浮选机中浮选萤石的最佳操作条件，采用悬浮状态判抓，计算包钢磁选铁精矿脱除萤石的反浮选精选3A浮选机的最佳转速应为420rpm，包钢选厂采用此参数在l_业件:产L取得了比395rpm(_「业分流试验)好，比洲or叩(分流试验调试初期)史好的浮选效果，得到萤石泡沫产率10.650/0，含从卜升」到16.1乃，氟脱除率上升到72.2%，铁精矿一中氟含量下降到0.7扭%，铁品位卜升到6l.l()%。 8.包钢选厂工业分流试验初期，磁选铁精矿反浮选脱氟精选过程和郑州中州铝!一铝土矿正浮选工业试验初期，都出现泡沫不被矿化的问题。经论文中试验、测定和计算己查明:在药剂条件适’fl{的条件下，浮选槽中矿浆紊流状态是影响泡沫征化不良的胜要原因。使用悬浮状态判据，根据小型浮选机试验操作条件推算人型浮选机理想操作条件，司一提高和改洱浮选厂浮选技术指标。紊流强度对浮选影响重人，此影响在不处于极端不良清况，·般不受重视和注意，但其转速不1定足报佳值，‘}二产技术指标也就不一定是最佳指标，!听以这个问题值得引起‘l:产{一的币视和注已。更多还原

【Abstract】 At the beginning stage of industrial partial flow test of low intensive magnetic separation-high intensive magnetic separation-flotation separation in the flotation plant of Baotou Iron and Steel Complex, the phenomenon of big and empty bubble was observed during the cleaning process of reverse flotation to remove fluorine from Iron concentrate of magnetic separation, similar phenomenon was observed when treating oxide ores such as bauxite and phosphate, the only difference is that the former is much more serious. It is a common phenomenon in industrial flotation, but it is caused little notice. This paper studied the reverse flotation process of fluorine removal from Iron concentrate of magnetic separation of Baotou Iron and Steel Complex and flotation process of Henan ZhongZhou bauxite ore. some relevant flotation questions have been systematically researched.l.The effect of the diameter of particles, aeration, the diameter of bubble and reagents on flotation have been studied with fluorine and hematite pure minerals in hallimond tube .It demonstrated that the recovery of fluorine increased with the increasing of the diameter of particles, aeration ,degree of agitation and with the decreasing of the diameter of bubble. Fluorine can float at a very low degree of agitation. Fluorine belongs to the minerals which can be easily floated. At the condition of pH equals 9,sodium silicate is used as depressant, NaOl is used as collector, Fluorine and hematite can be separated easily. According the photograph of fluorine froth, we can see that fluorine attaches on the bottom of the bubbles in the form of multiple particles.2.PDA(particle dynamics analyzer system) was used to measure the flow velocity of particles in the XFD-12 flotation cell, the results show that tangential mean velocity in the radial direction changes from positive to negative in the flotation cell, naught point emerge in the medium of the radial direction ,it is where backward fluid emerge ,shear stress of backward fluid induce the particle detachment from bubbles .Axial mean velocity of mixing region raised in the radial direction, that favors the suspension of particles near the cell. Axial mean velocities of flotation region increased at first and then decreased, power of suspension decrease in the radial direction. Axial relative velocities of flotation region and froth region decreased in the radial direction, the power of detachment decreased while the axial relative velocity decreased in the radial direction. The power of suspension of the non-mineralized particles and the detachment of mineralized particles increased while increasing impeller speed or turbulence degree.3. After balance forces of particles at the fluid interface were analyzed, we calculated the maximal diameter of flotation fluorine particle in the cleaning test of high magnetite concentrate of fluorite removal by reverse flotation. When impeller Reynolds increase from 0.16 Xl06 to 0.7 X 106 , the maximal diameter of flotation fluorine particle decrease from 0.134mm to 0.059mm.The results of sieve analysis show that while impeller Reynolds increase from 0.32 X 106 to 0.7 X 106 ,+0.()74mm range sieve fraction is quite limited,+0.054mm range sieve fraction decline from 9.25% to 4.58% andDoctoral dissertation ABSTRACT-0.054+0.038mm range sieve fraction decline froml3.68% to 8.3%.The results of calculating and sieve analysis show that coarse range sieve fraction of the cleaner decline while degree of turbulence increasing.4.The measured flow velocities by means of PDA in the XFD-12 flotation cell were used to calculate turbulence energy spectrum of mixing region, flotation region and froth region. The results have shown that turbulence frequency is less than 20HZ in the mixing region, in the flotation region between 20-30HZ, in the froth region between 25-35HZ. Turbulence energy in the mixing region is bigger that in the flotation region and bigger that in the froth regi更多还原