Study On Preparation Of Borax With Boron Containing Tailings

With the development of economy,science and technology,the important value of boron resources has become increasingly prominent.In China,about 60% of the boron resources are distributed in Liaoji area,the region is also the main mining area in recent years.Our boron reserves has plummeted after years of mining,and the grade of boron ore has decreased from the initial 20% to about 10%.Boron tailings are the tailings abandoned after enrichment of iron ore from paigeite,and the boron content is high.If not recycled,it will cause the loss of a large amount of boron,while the local soil and rivers will also be seriously polluted.In particular,the boron grade of boron tailings in the "Bojigou" area of Kuandian is up to 9.96%,which can be used as an alternative resource of boron mine.Therefore,the effective extraction of boron resources from boron tailings could be the solution of alleviating the shortage of boron products caused by the shortage of boron ore,and also be the solution of reducing the ecological pollution caused by tailings accumulation.In this paper,with the support of Land and Resources Public Welfare Industry Specialized(201411107-8),the boron tailings from "Bojigou" area and "Caojiagou" area were used as raw materials,to investigate the effects of foam flotation method and hydrocyclone method on the enrichment of boron-containing particles from the boron tailings.The effect of calcified roasting on the improvement of activity of boron of the boron tailings was investigated.The whole process route of preparation of borax by atmospheric alkaline hydrolysis of boron tailing was studied.Through a large number of experiments,the main factors of each process were analyzed and discussed,and the process parameters were optimized.The main contents of the thesis include:(1)In order to improve the grade of boron in tailings,the effects of foam flotation method and hydrocyclone method on the enrichment of boron-containing particles in tailings were investigated.For the foam flotation method,the effects of the concentrations of flotation auxiliaries,calcium lignosulfonate and sodium oleate,and the effect of pH value on the enrichment of boron-containing particles were studied.For the hydrocyclone method,the effects of the swirl frequency,the swirl pressure and the concentration of the slurry on the enrichment of boron-containing particles were studied.By optimizing the process parameters,the boron grade of the tailings has been greatly improved.(2)In order to improve the activity of boron in tailings,the effect of calcified roasting on the improvement of activity of boron was investigated based on the alkaloid ratio of boron.The effects of calcination temperature,calcination time,additive content and particle size on the activity of boron were analyzed.By optimizing the process parameters,the activity of boron is effectively improved.(3)The process of leaching boron compounds by atmospheric alkaline hydrolysis of boron tailing was investigated.Based on the leaching ratio of boron,the factors such as reaction temperature and reaction time of alkaline hydrolysis,concentration of alkali solution,and stirring rate were studied,and the process parameters were optimized.(4)The processes of converting boron in the form of sodium metaborate in the leaching solution of atmospheric alkaline hydrolysis to borax,and crystallizing of crude borax for purification were investigated.The effects of the pH value of the leaching solution and the addition of sodium bicarbonate on the conversion of borax were analyzed.The key factors affecting the crystallization process such as crystallization temperature and crystallization time,cooling mode,etc.,were discussed,and the processes were optimized.