Method for producing industrial grade superior ammonium sulfate through coked coarse ammonium sulfate dilution crystallization

Abstract

The invention particularly relates to a method for producing industrial grade superior ammonium sulfate through coked coarse ammonium sulfate dilution crystallization. According to the technical scheme, the method comprises the steps that the pH value of a coked coarse ammonium sulfate aqueous solution is adjusted through NaOH, activated carbon is further added, and the aqueous solution is filtered, so that a coked coarse ammonium sulfate crystallization mother solution is obtained; an acidity adjusting agent, a crystal habit modification agent and seed crystals are added to the mother solution, crystal is cultivated, and therefore suspended turbid crystal mush is prepared; finally, eluent is added to suspended turbid crystal mush flow, dilution crystallization is conducted, ammonium sulfate crystals are prepared through filtration and drying, the particle size distribution of a crystal product is concentrated, the surface is smooth, the purity is high, the liquidity is good, and the standard of an industrial grade superior product can be met. The particle size and the addition quantity of the seed crystals are changed so that the average particle size and the particle size distribution of the ammonium sulfate crystal product can be adjusted and controlled in the process of crystallization. The method for producing the industrial grade superior ammonium sulfate through coked coarse ammonium sulfate dilution crystallization has the advantages that the production cost is low, the production cycle is short, the average particle size is controllable, the particle size distribution is concentrated, one-way crystallization yield is high (no less than 95%), and the quality of the product is high.

Description

technical field [0001] The invention belongs to the technical field of industrial crystallization, and in particular relates to a method for producing industrial-grade high-quality ammonium sulfate by dissolution and crystallization of coking crude ammonium sulfate. Background technique [0002] Coking ammonium sulfate is a large industrial by-product of coke oven gas purification. A JN60-60 type 2×65 hole 7m 63 coke oven with an annual output of 2 million tons of coke can reach 30,000 t / a of ammonium sulfate. Since 1993, my country's coke output has been ranked first in the world, and it exceeded 400 million tons in 2011, so the output of domestic coking ammonium sulfate is huge. Ammonium sulfate is an important nitrogen fertilizer, and it can also be used as printing and dyeing agent, food catalyst, buffering agent, leather deliming agent and so on in industry. [0003] At present, most coking plants in China use the saturator method to produce ammonium sulfate. Coking ...

AI Technical Summary

Problems solved by technology

However, regardless of evaporative crystallization or cooling crystallization, crystal scale is easy to form on heat exchange surfaces such as coils or jackets, which significantly reduces heat transfer efficiency, makes it difficult to control the evaporation rate or cooling rate, and prolongs the crystallization time, resulting in a particle size distribution of crystallized products. Inhomogeneity, low production efficiency

Moreover, for the evaporative crystallization process, the solid-liquid suspension density in the crystallizer is getting higher and higher, the crystal-liquid mixing is uneven, the crystal is easy to sink to the bottom, and the friction and collision between the crystals and between the crystal and the stirring paddle causes the crystal to break during the crystallization process. Seriously, this will also aggravate the uneven particle size distribution of crystallized products

In addition, ammonium sulfate has a high solubility in water (0°C, 70g / 100g water). Regardless of evaporation crystallization or cooling crystallization, there will still be a large amount of uncrystallized ammonium sulfate in the mother liquor at the end of crystallization, resulting in low production capacity per unit volume crystallizer.

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