Process for the preparation of layered double hydroxides.

(57) The amount of summary carbonic acid ionic contamination decreases, and improved synthetic my クスネ light which has an X-ray diffraction image similar to having been shown figure 2 is indicated, and the my クスネ light, It manufactures by combining the activated alumina powder which has the BET specific surface area of about 100 or more m/g preferably with magnesium oxide and changes alumina in the environment which does not contain carbonic acid ion substantially. The method of manufacturing this synthetic my クスネ light output is also indicated.