Sodium sulphate preparation method and sodium sulphate foot structure of evaporator therefor

Abstract

The invention discloses a sodium sulphate preparation method and a sodium sulphate foot structure of an evaporator for the sodium sulphate preparation method. The method comprises the following steps of: (1) sequentially evaporating sodium sulphate liquid at least by a five-effect evaporator, a four-effect evaporator and a triple-effect evaporator, then evaporating the concentrated solution in the triple-effect evaporator in a double-effect evaporator and a single-effect evaporator separately, wherein a sodium sulphate liquid inlet is arranged at the middle lower part of the sodium sulphate foot of each of the double-effect evaporator and the single-effect evaporator, then introducing low sodium chloride raw-material sodium sulphate liquid from the inlets so as to decrease the temperature of the concentrated solution at the discharge port of the sodium sulphate foot in the evaporator to 70-80DEG C, and decrease the content of sodium chloride to 140-180 g / L; and (2) pumping the concentrated solution of temperature 70-80DEG C and sodium chloride content 140-180 g / L obtained in the step (1) into a thickening apparatus for thickening, separating the liquid from solid, feeding the obtained solid into a drying apparatus for drying, and pumping the mother solution of the thickening and drying processes into the triple-effect evaporator for recycling.

Description

technical field [0001] The invention relates to the technical field of Glauber's salt preparation, in particular to the concentrated liquid and the structure of the nitrate foot of the end evaporation tank in the Glauber's salt prepared from nitrate water of salt-associated ore. Background technique [0002] At present, the production of Glauber's salt from salt water from salt-associated mines requires evaporation, concentration and crystallization in multi-effect evaporators, and then liquid-solid separation to obtain Glauber's salt. In the liquid-solid separation step, the common method is to discharge the 250-280g / L concentrated solution containing sodium chloride at the end of the evaporation tank with a discharge temperature of 110°C or more and a sodium sulfate crystal content of more than 50%, and thicken it through thickening equipment. Thick, liquid-solid separation, and drying to obtain the finished sodium sulfate. The thickening equipment thickens and the mother...

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Problems solved by technology

Known from above-mentioned production process, existing production technology has following defect: the one, the concentrated solution temperature of discharge is higher, and heat loss is bigger in thickening and liquid-solid separation step, causes energy waste; The concentration of sodium chloride contained is relatively high, and the content of sodium chloride in the solid after liquid-solid separation is also relatively high, which cannot meet the requirements for the production of Class I and II Glauber's salt

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