选厂石灰添加自动控制系统研究

【作者】 张艳伟；

【导师】 李世厚；

【作者基本信息】 昆明理工大学 ， 矿物加工工程， 2008， 硕士

【摘要】 浮选实践和理论研究均已表明,调节矿浆的pH值对浮选工艺至关重要。对于特定的矿石及其相应的浮选工艺,只有在适宜的矿浆pH值条件下,才有可能获得较为满意的浮选效果。石灰是浮选作业中常用的pH值调整剂和铜、硫分离的重要抑制剂。在某些选矿过程中,石灰添加量的多少对浮选指标有重要的影响,石灰供给的均衡与稳定直接影响到精矿品位和回收率。某选矿厂选用石灰作为pH调整剂,通过石灰添加机将干石灰给入球磨机,从而调整矿浆pH值。现场工人用pH试纸,测粗选矿浆的pn值,再调节石灰添加量。现场要求十分钟测量一次,并相应的调整石灰添加量。测量及调整非常繁琐,而且由于人工调节受条件、责任心、劳动强度等外界条件影响,使pH值在一个比较大的范围内波动,控制精度远远不能满足浮选工艺要求。因此研究一套石灰添加自动控制系统具有很重要的意义。针对系统的要求和特点,研究了Smith预估控制算法、模糊控制算法和采样PI控制算法。通过比较研究,Smith预估控制算法不能用于数学模型不确定的过程。而模糊控制虽然不需要建立数学模型,但由于模糊控制器的规则和参数无法实时修改,控制效果并不理想。所以最终确定采用采样PI控制算法,该算法不需要建立精确的数学模型,编程实现容易,控制效果较好。利用Protel 99 SE电路设计软件,对下位机控制器的信号调理板、人机交互电路(按键面板、显示面板)以及控制器主板进行了设计。选用AT89S51单片机作为下位机控制器的核心器件;选用BPHM-I矿浆专用pH传感器检测矿浆的pH值;A/D转换选用ADC0809芯片;D/A转换选用DAC0832芯片。在上述硬件电路及控制算法的基础上,利用C语言,开发了pH控制器的控制软件。系统在软件上采用模块化的程序结构,包括算法控制程序、显示程序、参数设置程序及一些辅助的子程序等,并从硬件和软件两方面对系统的抗干扰性能进行了设计。为了便于整个选厂自动化的实现,利用pH控制器的串口实现与上位机的实时通讯。上位机实时监控pH值的变化,并进行报表打印、实时和趋势曲线以及报警窗口显示等。更多还原

【Abstract】 The practice of flotation process and the fundamental research have proven that the adjustment of pulp’s pH value is very important.Regarding specific ore and corresponding flotation process craft,it is possible to obtain more satisfactory effect of flotation process under the suitable condition of pulp’s pH value.The lime is the commonly used as the regulator of pH value and the important inhibitor of the separation of the copper and the sulfur in the practice of flotation process.The amount of adding lime has the important influence to the target of flotation process.The balance and stabilitation of supply lime directly affect the status of ore concentrate personal and the returns-ratio.The lime is used as the pH regulator in some concentrators.The machine of lime add the lime into the ball mill in order to adjust the pulp’s pH value.The pH indicator paper is used to measure the rough end’s pH value,then adjust the amount of adding lime by manual labour. The concentrators requests measuring every ten minutes,and corresponding adjustment the adding of lime.Because the measurement and the adjustment is extremely tedious and the manual regulation is influenced by worker’s responsibility and labor’s intensity,the pH value is fluctuated in a so larger scope that the precision of controlment cannot satisfy the requirement of the flotation process.Therefore it is very important to design the automatic control system of adding the lime.Considering the request and characteristic of the system,we have studied the control algorithm of Smith estimate,the fuzzy control algorithm and the sampling PI control algorithm.Through the comparison research study,we have found that the control algorithm of Smith estimated cannot be used in the process of indefinite mathematical model.Although the fuzzy control algorithm does not need to establish the mathematical model,the rule and the parameter of fuzzy controller are unable to be repaired in the real-time.So the control effect is not ideal.Therefore we finally determine to use the sampling PI control algorithm. The algorithm does not need to establish the precise mathematical model,the programming realization is simple and the control effect is good.Using the software of Protel 99 SE,we have designed the board of signal recuperation and the motherboard of controller.AT89S51 is used as the core component.The sensor of the BPHM-I pulp is used to examine the pulp’s pH value.We selects the ADC0809 chip as A/D switch and the DAC0832 chip as the D/A switch.Using the language of the C,we have designed the control software of the pH control software.The system uses the modular of procedure structure,including the procedure of controlment algorithm,the demonstration procedure,the parameter establishment procedure and some assistant procedures.We have carried on the design of system anti-jamming from both the hardware and the software.In order to realize the automation of entire factory,we use the serial port of the pH controller realizing the real-time communication with computer that monitor the changement of pH value,print the report form、the real-time curve and trendline and show the window of the alarm and so on.更多还原