The invention relates to an extracting and separating method and a device for waste acid generated in the production procedure of m-
dinitrobenzene, which belong to the technical field of
chemical engineering. By applying the principle of an extraction technology, the invention provides a process for finishing the extraction of a
nitro compound in waste acid generated in the production procedure of m-
dinitrobenzene by utilizing an ejector and a static mixing
pipe and also realizing liquid-liquid separation by a tilted plate separator. According to the extracting and separating method and the device for the waste acid generated in the production procedure of the m-
dinitrobenzene, waste acid with the
mass concentration of 68 to 75 percent, which is generated in the production procedure of
benzene and m-dinitrobenzene, is mixed by the ejector, is mixed by the static mixing
pipe and is separated by the tilted plate separator, so that
nitrobenzene and dinitrobenzene in the waste acid are extracted, and the content of nitro matters and
nitric acid in the waste acid is lowered. According to the extracting and separating method and the device for the waste acid generated in the production procedure of the m-dinitrobenzene, liquid is ejected in a
fog shape after the liquid passes through the ejector, and is also mixed by the static mixing
pipe fully so as to finish an extraction reaction. The content of a nitrated compound in the waste acid with the m-dinitrobenzene is lowered below 0.1 percent after separation from 0.6 to 0.7 percent before separation, the waste acid after being extracted is in concentrating treatment again, the
energy consumption and the cost are low, and the
pollution of the environment is lowered.