Method for producing fully-water-soluble potassium sulfate from waste/inferior potassium chloride

Abstract

The invention discloses a method for producing fully-water-soluble potassium sulfate from waste / inferior potassium chloride. The method comprises the following steps: (a) dissolving the waste / inferior potassium chloride into water so as to obtain a potassium chloride mixed solution, filtering the potassium chloride mixed solution so as to obtain a clear potassium chloride solution, and removing impurities from the clear potassium chloride solution by using a chemical solution; (b) mixing the clear potassium chloride solution with a clear ammonium sulfate solution, so as to prepare a potassium ammonium sulfate mixed solution; (c) carrying out solid-liquid separation on the potassium ammonium sulfate mixed solution, so as to obtain potassium ammonium sulfate crystals; and (d) adding water and a catalyst into the potassium ammonium sulfate crystals, carrying out purification so as to obtain potassium sulfate, and carrying out solid-liquid separation and baking on potassium sulfate, thereby obtaining finished potassium sulfate. According to the method, the fully-water-soluble potassium sulfate can be prepared from the waste / inferior potassium chloride, and thus the aims of recycling wastes and avoiding environmental pollution are achieved.

Description

technical field [0001] The invention relates to potassium sulfate preparation technology, in particular to a method for producing fully water-soluble potassium sulfate by utilizing waste potassium chloride. Background technique [0002] Potassium sulfate is an important chlorine-free potassium fertilizer, which is used in economic crops such as tobacco, citrus, tea, grapes, sugar beets, sugar cane, etc. Potassium contained in it is one of the three major nutrients for plants, and sulfur is the medium amount required by plants Nutrient elements, especially suitable for chlorine-avoiding crops, are a multi-nutrient and versatile fertilizer. In addition, potassium sulfate is also a basic chemical raw material, which is widely used in pharmaceutical, glass and dye industries. However, due to the lack of potassium resources, there is a considerable gap between production and demand, so potassium sulfate has to rely on imports to a large extent, especially fully water-soluble pot...

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Problems solved by technology

[0004] However, the prior art represented by this patent still has the following defects in the actual application process: 1. If the washing water consumption is large in the fifth step, the energy consumption will be large; if the water consumption is small, the ammonium residue will be large , easily affect the purity of potassium sulfate product

2. The two washings of crude potassium sulfate will take away a large amount of potassium oxide, and the main product will remain in the liquid ammonium chloride. After the solid state, there will be too much potassium in the ammonium chloride, which will reduce the main product potassium sulfate. The recovery rate has affected the purity of the by-product ammonium chloride

Three, the fifth step adopts centrifugation to separate potassium sulfate, which has the defects of small yield and difficulty in large-scale formation of high yield

Four, no catalyst is used in the preparation process of potassium sulfate, it is difficult to effectively and accurately control the purity of chloride radicals and products

5. The process of this method is complicated and professional, and it is difficult for workers to implement the process skills accurately and effectively during production.

Six, the water-solubility of the potassium sulfate that existing ammonium sulfate method (comprising Mannham method) makes is all only about 88%, exists the defect that scales easily and impurity forms clogging, can not be used for large-scale drip irrigation Fertilization device, automatic irrigation and fertilization device, pipeline irrigation and fertilization device and nozzle fertilization device

7. There is no purification of ammonium chloride, resulting in too much residual potassium oxide in the by-products, and the low economic benefits are the reasons why this technology cannot be popularized and implemented in China

8. This method cannot use waste potassium chloride as a raw material, which leads to higher production costs and is difficult to win in long-term competition

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