Preparation of nano magnesium hydrate

Abstract

The invention relates to a preparation method of nano-sized magnesium hydroxide, which is characterized in that a soluble magnesium salt solution and soluble lye which are added with a dispersant react in a reactor which is put in an ultrasonic tank and provided with a stirrer to obtain magnesium hydrate suspension; the magnesium hydrate suspension is processed through ultrasonic ageing at room temperature; the magnesium hydrate which is processed through ageing is dried through heating to obtain nano-sized magnesium hydroxide powders after being filtered and washed. The ultrasonic wave which is exerted during the reaction process promotes the nucleation, inhibits crystal nucleus growth velocity, and controls the size and the distribution of particles; the ultrasonic cavitation avoids the occurrence of aggregate phenomenon, and increases the uniformity and the dispersibility of nano particles; the thermal effect of the ultrasonic wave increases the crystallinity degree of the nano particles and shortens the ageing time of samples. Therefore, the preparation method has the advantages of simple technology, short production period, mild production conditions, good product dispersibility, and even particle distribution.

Description

technical field [0001] The invention belongs to a nano powder preparation process, in particular to a preparation method for ultrasonic-assisted synthesis of nano-powder, in particular to an ultrasonic-assisted synthesis method for nano magnesium hydroxide. Background technique [0002] Mg(OH) 2 As an important inorganic flame retardant, it is one of the most cost-effective flame retardants. It has the characteristics of high decomposition temperature, high thermal stability, non-toxic, smoke-free and smoke-suppressive, and is an environmentally friendly and green flame retardant. Moreover, most of the properties are better than aluminum hydroxide flame retardants, which cater to the needs of non-halogenated, low-toxicity, and smoke-suppressing flame retardants in the 21st century, and have achieved rapid development. But ordinary Mg(OH) 2 It is used for flame retardancy of polymers, the flame retardancy efficiency is low, and the compatibility with the matrix is ​​poor. ...

AI Technical Summary

Problems solved by technology

The equipment investment of this method is large, and the magnesium hydroxide generated by the reaction is easy to deposit in the gap between the fillers and block the packed bed.

Chinese patent CN1542036A uses soluble magnesium salt and soluble alkali as raw materials. Under the action of polymer protective agent, magnesium hydroxide nanopowder is prepared by forced emulsification and precipitation through a high-shear homogeneous emulsifier. The aging time after the reaction is long Up to 12 hours, the reaction time is too long

Chinese patent CN1982410A combines precipitation synthesis and hydrothermal treatment to prepare magnesium hydroxide by precipitation method to prepare flaky nano-magnesium hydroxide. The reaction and hydrothermal treatment temperatures are as high as 160°C and 180°C respectively. The reaction conditions of this method are harsh and difficult to operate. Difficult, difficult to industrialize production

This patent uses ultrasonic waves to vibrate the pre-prepared magnesium hydroxide colloid, which has the function of ultrasonic dispersion to prevent agglomeration, but the ultrasonic time is too long, especially the solvent is removed by evaporation, which makes the patented method have a long production cycle, high energy consumption and high cost. , is not conducive to the promotion of industrialization

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