[Subject] To provide a low price industrial salt by reducing facility and operation costs without electrodeposition and crystallization and through reduction in quantity of chemicals used.
[Means for Solution] An industrial salt S obtained by the steps of: extracting a part of combustion gas from a kiln exhaust gas passage running from an inlet end 12b of a cement kiln 12 to a bottom cyclone 13; recovering dust D from the extracted gas G2 and washing recovered dust; and drying a filtrate L1 after the washing in a gas stream. The industrial salt can be obtained by removing a calcium component from the filtrate and drying the filtrate from which the calcium component is removed in a gas stream. Further, from the filtrate can be removed sulfate radical, and drying the filtrate from which the calcium component is removed in a gas stream to obtain the industrial salt. For the drying can be used an exhaust gas discharged from a clinker cooler 12a and a spray drier 43 may be used for the drying. Drying in a stream provides industrial salt whose particle size is larger or equal to 20µm and smaller or equal to 500µm.