Abstract: Provided is a wastewater purification method, the method including: supplying a first mixed stream, in which an acid component and wastewater including water, a nitrile-based monomer, and ammonia are mixed, to a first column; recovering the nitrile-based monomer from an upper discharge stream from the first column; supplying a second mixed stream, in which a lower discharge stream from the first column and a base component are mixed, to a second column; and recovering the ammonia from an upper discharge stream from the second column and separating purified wastewater.

Abstract: This invention provides a method and apparatus to produce metal or alloy ingots using spray casting with the features of easy manufacture of large diameter ingots and simultaneously their uniform microstructure due to followings. Firstly, spray deposition area on the top surface of the ingot can be enlarged by making use of multiple gas atomizers and also by controlling the their positions for the spray deposition. Secondly, at the same time, a mutually opposite-directional rotation between the gas atomizers and the catching plate provides a uniform deposition of sprayed droplets along the circumference-wise direction over the entire top surface of the ingot. In addition, a mutually opposite-directional reciprocation between the gas atomizer and the top surface of the ingot provides an enlargement of deposition area and an evenness of spray deposition along the radial direction on the top surface of the ingot.