Method for preparing potassium sulfate from brine with low sulfur-potassium ratio

Abstract

The invention discloses a method for preparing potassium sulfate from brine with a low sulfur-potassium ratio. The method includes steps of (1), evaporating the raw brine to obtain potassium-mixed salt mine; (2), sun-curing carnallite; (3), feeding the carnallite to a potassium chloride workshop, and carrying out crushing, decomposing, flotation and dehalogenation on the carnallite to obtain potassium chloride concentrate; (4), feeding the potassium-mixed salt mine to a picromerite workshop, crushing the potassium-mixed salt mine, mixing the potassium-mixed salt mine and tailings with one another in water after the tailings obtained at the step (3) are subjected to dehalogenation, and carrying out grinding, transformation, flotation, separation and washing to obtain picromerite concentrate; (5), mixing the picromerite concentrate and the potassium chloride concentrate with each other in water to obtain mixtures and transforming the mixtures to obtain potassium sulfate products. The method has the advantages that technical routes of existing processes for producing potassium sulfate from salt lakes are improved, accordingly, shortcomings of methods for producing the potassium sulfur from brine with a low sulfur-potassium ratio in the prior art can be overcome, and the reasonable and feasible method which includes simple processes and short procedures and is low in cost and free of pollution can be provided for producing the potassium sulfate from the brine with the low sulfur-potassium ratio from salt lakes.

Description

technical field [0001] The invention relates to a method for preparing potassium sulfate from brine, in particular to a method for preparing potassium sulfate from brine with a low sulfur potassium ratio. Background technique [0002] Potassium sulfate is an important chlorine-free potassium fertilizer, which is widely used in agriculture and has a large market demand. In the present technology, CN1439602 discloses the method for producing potassium sulfate with potassium-containing magnesium sulfate subtype brine, the method obtains langbeinite mixed salt through conversion, decomposition and flotation, and then uses Soft langbeinite and potassium chloride are converted into potassium sulfate by adding water. [0003] U.S. Patent No. 3.589.871 (1971) discloses a method for producing potassium sulfate from sulfate-type brine. In this method, the composition of sulfate-type brine is adjusted by adding brine, and then the brine is obtained by drying in salt fields, and then t...

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Problems solved by technology

[0004] The above two methods of using salt lake brine to produce potassium sulfate are only suitable for producing potassium sulfate with brine with relatively large sulfur-potassium ratio (the ratio of sulfur-potassium is generally higher than 4), but for brine with relatively low sulfur-potassium ratio, if using this method Potassium sulfate production, because the ratio of sulfur and potassium in the potassium mixed salt ore obtained from the salt field is low (generally lower than 2.5), the sulfate radical is obviously insufficient, the ratio of sulfur and potassium does not match, and the conversion of ore dressing and grinding cannot be achieved-flotation langbeinite Ideal technological requirements cause the yield of langbeinite to be low and the grade is not high, which reduces the output of potassium sulfate to a certain extent

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