Research On Technology Of On-line Microwave Detection Of Moisture In Iron Ore Concentrate At Port

Iron industry is an important index of Chinese economic. As the second largest economicentity, China has an increasing demand in iron ore concentrate, the import volume increases sharply.However, due to the shortcomings of imported ore moisture detection method, the quality disputeoften occurs, which causes severe damage to iron and steel enterprises. Therefore, according to thethe urgent need of port online moisture detection for inspection and quarantine department,exploring and developing an instrument of on-line detection of moisture content of the iron oreconcentrate is more necessary.This study expounds various moisture detection methods and their technology applicationsituation, analyzes the weakness of the current port drying weighing method generally used,because of the lagged sampling point, traditional method cannot reflect the lost water in ironconcentrate during unloading and long distance transportation by belt and thus leads to largerdeviation of moisture detection, therefore, proposes to use microwave transmission method to detectthe moisture in iron ore concentrate online.This study analyzes the application of microwave moisture detection technology, experimentconducts solid-liquid two phase mixture permittivity, verifies the feasibility of microwavetransmission method in detecting the moisture content in the iron ore concentrate and obtainsmathematical model which is applied to iron ore concentrate moisture detection. Through furthertheoretical analysis, this study puts forward the main performance index of the on-line microwavemoisture detection and designs the overall scheme of the port iron ore concentrate onlinemicrowave moisture detection system including signal transceiver system and signal processingsystem module; Based on port’s actual working environment and special requirements, this studyproduces an special sensor used for iron ore concentrate microwave moisture detection, itsperformance indicators VSWR (standing wave ratio) is1.053, the gain is16.85dB; this studydesigns the signal processing hardware circuit system with modular, and completes the productionand testing; compiles the embedded program of corresponding hardware and completes the jointdebugging between hardware and software.Finally, on the basis of theoretical analysis, this study builds a set of iron ore concentrateon-line microwave moisture test system applied to the port, using the vector network analyzer andsignal processing device, conducts tests of the impact of transmission belt and thickness ofthickness on microwave phase shift, joint debugging of iron concentrate online microwave moisturedetection system. Tests and experimental research show that the impact of ports transmission belt for the performance of microwave signal is S21(positive transfer coefficient) which variation is8.465dB; The best measured thickness of iron ore concentrate in transmission belt is19mm~21mm; ignoring the impact of transmission belt and the thickness of the iron ore concentrate,compares the data obtained with drying weighing method and the average error is0.145%, which isless than0.2%designed accuracy.Through theoretical analysis and experimental tests, it shows that the proposed port iron oreconcentrate online microwave moisture detection system can meet the precision requirement, thusthe scheme is feasible, and through further improvement and site test, it is expected to be directlyapplied port operation and has guiding significance in improving the quality of China’s imports ofiron ore concentrate and detection level.