Solid/liquid separation apparatus, and method for same

A solid-liquid separator that uses a substance A capable of dissolving water and oil, and performs dehydration and deoiling from an object to be treated that is a mixture of water and a solid, oil and a solid, or water, oil and a solid, the solid-liquid separator comprising:

• a treatment tank containing the object to be treated;
• a first heat exchanger;
• a second heat exchanger;
• a compressor;
• an expansion valve;
• a substance A flow path which circulates the substance A from the treatment tank to the first heat exchanger, from the first heat exchanger to the second heat exchanger, and from the second heat exchanger to the treatment tank, wherein the substance A flow path forms a single-loop closed system of flow from the treatment tank to the first heat exchanger, from the first heat exchanger to the second heat exchanger, and from the second heat exchanger to the treatment tank;
• a pump to circulate the substance A through the substance A flow path;
• and
• a substance B flow path which circulates a substance B from the first heat exchanger to the expansion valve that decompresses the substance B which is condensed, from the expansion valve to the second heat exchanger, from the second heat exchanger to the compressor that compresses the substance B, and from the compressor to the first heat exchanger, in a closed system;
• wherein the first heat exchanger exchanges condensation heat of the substance B and evaporation heat of the substance A;
• wherein the second heat exchanger exchanges evaporation heat of the substance B and condensation heat of the substance A;
• wherein the condensed substance A, which is condensed in the second heat exchanger after the substance A evaporates while separating from water or oil in the first heat exchanger, and the object to be treated, are mixed in the treatment tank;
• wherein the solid in the object to be treated contains a magnetic substance;
• and
• wherein the solid-liquid separator further includes a magnetic separating device to separate the magnetic substance from the solid in the object to be treated.