Preparation And Modification Of Manganese Barium Magnetic Materials

Chengkou county as the largest resources county in Chongqing city,riched in mineral resources,more than 20 kinds of minerals,such as manganese,barium,coal,lead,zinc.Among them,manganese and barium are the most representative mineral resources in the county.However,the barium ore is mainly developed in the mine,only to do a simple physical processing and marketing,high performance and high added value of barium chemical materials also need a large number of imports.Manganese products are mainly ore,roasting ore,electrolytic manganese,manganese dioxide,etc.the backward production technology,low comprehensive utilization of manganese resources,bring about large energy consumption and serious environmental pollution,so,energy-saving and emission-reduction task is still very heavy.In short,although the city is rich in mineral resources,the technical level of manganese barium industry lags behind,it is urgent for us to exploit the resources of manganese and barium,and to break through the key technologies of new technologies,new processes and new equipment,our core is to achieve the technology of our industry to reach or close to the world advanced level,so as to promote the rapid development of Chengkou county economy and transform the resource superiority into economic superiority.Barium ferrite has been widely concerned with its cheap raw materials and excellent chemical stability since its development in 1950 s.It is widely used in many fields,such as motor,motor rotor,magnetic recording,microwave absorbing materials and so on.In recent years,due to the rapid development of science and technology,all walks of life put forward higher requirements on the propertise of barium ferrite materials,it is urgent for us to develop low cost and high performance barium ferrite materials.Based on the above problems,this paper from the comprehensive utilization of Chengkou County manganese and barium ore perspective,the corresponding elements are extracted to prepare magnetic materials with excellent properties.Based on this,the four kinds of rare earth elements(La,Ce,Nd,Dy)and strontium elements were used to modify the ferrite material in order to obtain the better ferrite products.The main research contents and conclusions are as follows:(1)In the process of mineral leaching,we explored the process conditions and the process route and parameters of the hydrochloric acid wet leaching mineral.Through experimental results that: the best experimental conditions for leaching manganese ore was the liquid-solid ratio is 8:1,the mineral acid mass ratio is 1:1.4,the reaction temperature was 70 centigrade,the reaction time was 2h,the leaching rate of manganese was about 83%.The optimum experimental conditions of barium ore leaching was the liquid-solid ratio 8:1,the mineral acid mass ratio was 1:1.1,the reaction temperature was 80 centigrade,the reaction time was 4h,the barium leaching rate is 75%.Increasing the amount of hydrochloric acid,leaching time and leaching temperature,leaching rate is not significantly increased,but will increase the cost and energy consumption of the leaching process(2)Removal of Ca and Mg ions in the leaching solution of manganese and barium by multi-step complex precipitation method,at the same time,the loss rate of manganese and barium ions was also considered,the effect of temperature on the removal rate of impurity ions was investigated.When the reaction temperature is 65 centigrade,the removal rates of calcium and magnesium ions in manganese ores were 82%,manganese ion loss rate was 2.9%.The removal rate of calcium and magnesium in barium ore leaching solution is 86%,and the loss rate of barium ion is about 8.8%,Therefore,we should balance the removal rate and loss rate in the process of impurity removal,select the appropriate impurity removal conditions.(3)Synthesis of manganese barium ferrite by chemical coprecipitation method,The effects of precipitation pH,calcination temperature and calcination time on the preparation of manganese barium ferrite were investigated,The results show that: The calcination temperature and calcination time have a great influence on the formation of manganese barium ferrite,When the temperature rises above 1000 centigrade,the obtained manganese barium ferrite material has high crystallinity and good micro morphology;A high saturation magnetization of 40.5emu/g and a maximum coercivity of 4000 Oe were prepared by the precipitation of pH=9,calcination temperature of 1000 and calcination time of 2h.(4)For the rare earth ions and strontium ion doping experiments,the effects of different rare earth elements and doping on the phase,morphology,magnetic properties and microwave absorbing properties were investigated.The results show that the doping of rare earth ions greatly increases the coercivity of the material and the saturation magnetization of the material is greatly increased by the addition of strontium ions,When the light rare earth Ce ions are doped,the coercivity reaches 5000 Oe.The rare earth doped materials have good absorbing properties at high frequency,and the minimum reflection loss is-15.7dB.When the strontium ion was doped with x=0.6,the prepared material had the best performance,the saturation magnetization was enhanced to a maximum of 67emu/g,and the coercive force was 5534 Oe.