11.By technique checking every operations of recovery circuit,calculating the classification of spitzkasten and cyclone,thickening efficiency,assaying the ash of every operations.
12.Bilateral oal thickenings of the surface ectoderm, called nasal placodes, then deelop on each side of the inferior part of the frontonasal prominence.
外胚层表面呈双边卵圆形增厚形成鼻板,然后发展成为额鼻隆起的下半部分。
13.The composition. properties, reaction activity, capacity of frothing and defrothing of phosphate rock and the preparation, thickening and clarification of wet phosphoric acid are stutiied.