Preparation method and process of pharmaceutical and food grade magnesium oxide dry granulation

At present,the global market for magnesium oxide is huge,and only a few companies from Israel and Japan own this product.Due to war and technological confidentiality,Israel is currently unable to know its production process.The existing technology involves mixing two types of magnesium oxide in proportion,then pressurizing and crushing the mixture.Magnesium oxide requires calcination of magnesium

         At present,the global market for magnesium oxide is huge,and only a few companies from Israel and Japan own this product.Due to war and technological confidentiality,Israel is currently unable to know its production process.The existing technology involves mixing two types of magnesium oxide in proportion,then pressurizing and crushing the mixture.Magnesium oxide requires calcination of magnesium hydroxide at different temperatures,which is a complex process and requires professional BET specific surface area instruments to determine.Domestic magnesium oxide mainly consists of primary crude products such as lightweight magnesium oxide.If there is a particle size requirement for magnesium oxide,it is generally produced by calcining magnesium hydroxide or crushing or sieving magnesium oxide.However,the magnesium At present,the global market for magnesium oxide is huge,and only a few companies from Israel and Japan own this product.Due to war and technological confidentiality,Israel is currently unable to know its production process.The existing technology involves mixing two types of magnesium oxide in proportion,then pressurizing and crushing the mixture.Magnesium oxide requires calcination of magnesium hydroxide at different temperatures,which is a complex process and requires professional BET specific surface area instruments to determine.Domestic magnesium oxide mainly consists of primary crude products such as lightweight magnesium oxide.If there is a particle size requirement for magnesium oxide,it is generally produced by calcining magnesium hydroxide or crushing or sieving magnesium oxide.However,the magnesium oxide obtained by this treatment method is not compressible.

         The present invention relates to a preparation method for food additive magnesium oxide,in particular to a preparation method for magnesium oxide suitable for dry granulation,which is a preparation method for magnesium oxide with compressibility,high magnesium oxide content,low heavy metal content,and low packing density.Including the following steps:

         (1)Using magnesium carbonate as raw material,grind magnesium carbonate to obtain its particle size;

          (2)The obtained magnesium carbonate will be calcined at high temperature to generate magnesium oxide,wherein the high-temperature calcination includes a heating calcination stage and an insulation calcination stage.The calcination temperature of the entire calcination stage is controlled at 720-850℃,with a heating calcination time of more than 1 hour and an insulation calcination time of 4-10 hours.

          Setting the grinding particle size,calcination temperature,heating calcination time,and insulation calcination time of magnesium carbonate within the above range can control the fineness of magnesium oxide.During the calcination process,a high calcination temperature can cause a sharp shrinkage of magnesium carbonate particle size.A low temperature can lead to insufficient combustion of magnesium carbonate,and a short heating and calcination time can also cause a sharp shrinkage of magnesium carbonate particle size.Therefore,the magnesium carbonate particle size,calcination time,and calcination temperature set in the present invention can ensure sufficient calcination of magnesium carbonate,thereby ensuring the compressibility of magnesium oxide.

          The magnesium carbonate is ground to a powder particle size d90 of 35-50um.By keeping the particle size of magnesium carbonate within the above range,the particle size of magnesium oxide can be controlled,resulting in higher hardness of the prepared tablets and no adhesive impact,thereby improving the success rate of tablet manufacturing.

           The calcination temperature is 750-800℃.Research has found that the calcination temperature of magnesium carbonate within the above range can further ensure the full combustion of magnesium carbonate,reduce the calcination cost,and thus lower the preparation cost of magnesium oxide.

            The heating and calcination time is 1-2h.Research has found that by setting the heating and calcination time within the above range,magnesium carbonate can be fully burned.If the heating and calcination time is less than 1 hour,it will cause a sharp shrinkage of magnesium carbonate particle size,affecting the prepared magnesium oxide particle size and its compressibility.If the heating and calcination time is extended to more than 2 hours,this operation is difficult to implement in practice and increases the calcination cost.

             The insulation calcination time is 4-8 hours.Setting the insulation calcination time within the above range can ensure the full combustion of magnesium carbonate and the compressibility of the prepared magnesium oxide,while reducing calcination costs,making it suitable for industrial production.

              The magnesium carbonate is generated by the reaction of MgCl solution and sodium carbonate solution,which is washed with water and dried to form magnesium carbonate crystals.After research,it was found that magnesium oxide prepared by changing the raw material to magnesium hydroxide or magnesium sulfate using the same method has no compressibility.

             Compared with existing technologies,the present invention controls the particle size of magnesium carbonate,high-temperature calcination temperature,and heating and insulation calcination time to generate magnesium oxide after calcination.At the same time,it ensures the compressibility of magnesium oxide,high purity of magnesium oxide,greatly improves the success rate of magnesium oxide in tablet manufacturing,and increases the hardness of the tablet,making it more convenient to store and transport the tablet,thereby reducing the manufacturing cost of magnesium oxide particles.