Study On Synthesis Mechanism And Process Of Disodium Octaborate Tetrahydrate

Disodium Octaborate Tetrahydrate has a broad prospect of application in thecontemporary society.With the development of science and technology and the national economic construction,not only the quantity for Disodium Octaborate Tetrahydrate will continue to grow,but also the requirement for its quality will continue to increase.Thus it will promote tremendous progress in agriculture,industry,medicine and health and other industries if we develop the production of Disodium Octaborate Tetrahydrate.At the present,less effort of the system research on the synthesis of Disodium Octaborate Tetrahydrate was made in China,moreover,the synthetic products are of low purity,most of which are applied to agriculture,the application of Disodium Octaborate Tetrahydrate in other fields is limited accordingly.Therefore,it is necessary to research and explore meticulously on the process parameters,the structure of product and synthesis mechanism in the production process.This paper has researched systematically on the process of polymerization reaction of Disodium Octaborate Tetrahydrate by using different raw materials.Firstly,Na OH and H3BO3 are used as raw materials to synthesize Disodium Octaborate Tetrahydrate by wet chemistry method.The effect of reactant ratio,reactant concentration,reaction time and reaction temperature etc,on the synthesis of Disodium Octaborate Tetrahydrate were investigated,respectively.And the effect of cooling time,cooling rate,and cooling temperature on the morphology and crystallinity of the product were also investigated.The results indicated that the suitable synthesis parameters are as follows: m(Na OH)/m(boric acid)=0.234,m(H2O)/m(H3BO3)=1.5,reaction time of 90 min,and reaction temperature of 100?,stirring speed of 70 r/min,cooling time of 50 min,cooling temperature of 25?.Secondly,borax and boric acid are used as raw materials to synthesize Disodium Octaborate Tetrahydrate by the same method.The results indicated that the suitable synthesis parameters are as follows: m(borax)/m(boric acid)=2.158,liquid-to-solid ratio of 0.95 ml.g-1,reaction time of 90 min,and reaction temperature of 100?,and cooling time of 30 min,cooling temperature of 20?,and stirring speed of 150 r/min.In the process of research,the content of B2O3 of the product was determined through chemical analysis;and the crystalline phase and morphology of the product were characterized by XRD and SEM,the results showed that Disodium Octaborate Tetrahydrate was an amorphous material;the reaction product and the supersaturatedsolution of reaction product were analyzed by IR and Raman spectra,according to the attribution of IR and Raman vibration bands of borate anions,predicted that the FBB of Na2B8O13.4H2 O was composed by a three-membered ring of B3O3 and a double three-membered ring of B5O10 connected by an oxygen atom.B3O3(OH)4-and B5O6(OH)4-are the main borate anions in the reaction solution,when PH=5.5-6,and Disodium Octaborate Tetrahydrate was synthesized by B3O3(OH)4-and B5O6(OH)4-through polymerization.