CN105692673A - Preparation method of potassium alum - Google Patents

Abstract

The invention relates to a preparation method of potassium alum. The preparation method comprises mixing aluminum sulfate, potassium sulfate and water at a temperature of 80-100 DEG C so that the materials undergo a reaction, carrying out evaporative concentration on the reaction product, adding a seed into the product and carrying out cooling crystallization to obtain potassium alum crystals. The potassium alum crystal has the characteristics of uniform particle size distribution and large average particle size.

Description

A kind of preparation method of potassium alum

Technical field

The invention belongs to industrial crystallization technical field, the preparation method being specifically related to a kind of potassium alum。

Background technology

Potassium alum, KAl (SO₄)₂ ·12H₂O, is commonly called as Alumen, Potassium aluminum sulfate dodecahydrate etc.。Potassium alum is the double salt of the potassium sulfate containing water of crystallization and aluminum sulfate, and colourless cubic crystal is dissolved in water, insoluble in ethanol。Potassium alum has antibacterial, astriction etc., can be used as Chinese medicine；Can be additionally used in preparation aluminium salt, yeast powder, paint, clarifier, mordant, papermaking, waterproofing agent etc.。In daily life, potassium alum can be additionally used in water purification and edible extender。

The commercial production of potassium alum is frequently with alunite method and recrystallization method。Alunite is non-water-soluble potassium aluminium sulfate mineral, first it is carried out flour, roasting (dehydration, pyrolysis or reduction pyrolysis), again through wet extraction (acid system, alkaline process or using acid and alkali combination method), prepare potassium alum finally by crystallization technique。Alunite method prepares the shortcomings such as potassium alum has process route complexity, production cycle length, energy consumption is high, three wastes yield is big, product quality is low, ore resource utilization rate is low。Recrystallization method is with industry potassium alum or containing K⁺、Al³⁺And SO₄ ^2-Material be raw material, prepare high-purity potassium alum by recrystallization。

Summary of the invention

It is desirable to provide the potassium alum preparation method that a kind of product particle mean size is big。

For achieving the above object, the comprising the concrete steps that of the technical solution used in the present invention:

Step one, first by following proportioning, aluminum sulfate, potassium sulfate and water being carried out dispensing, wherein: aluminum sulfate is 20 ~ 25wt%, potassium sulfate is 10 ~ 13wt%, and all the other are water；Again normal pressure, 80 ~ 100 DEG C and 150～500r/min speed conditions under stirring 1 ~ 2h prepare potassium alum crystalline mother solution I；

Step 2, at normal pressure or when vacuum is 0.02 ~ 0.05MPa, by step one prepare potassium alum crystalline mother solution I evaporation and concentration to solution density be 1.25 ~ 1.35g/mL, prepare potassium alum crystalline mother solution II；

Step 3, normal pressure, 80 ~ 100 DEG C and 150～500r/min speed conditions under, in the potassium alum crystalline mother solution II that step 2 prepares, add crystal seed, insulated and stirred 0.5 ~ 1h, prepare suspended magma；

Step 4, under the speed conditions of normal pressure and 150～500r/min, the suspended magma that step 3 prepares is cooled to 25 ~ 35 DEG C with the speed of 1～10 DEG C/h, then filters, washing, dry；Prepare the potassium alum crystal that mean diameter is big, filtrate and washings and return step one recycled。

Described crystal seed is Potassium aluminum sulfate dodecahydrate crystal, and Seed charge is 0.1～5wt% of potassium alum crystalline product gross mass。

Detailed description of the invention

Below in conjunction with detailed description of the invention, the invention will be further described, not the restriction to its protection domain。

Embodiment

A kind of preparation method of potassium alum, it comprises the concrete steps that:

Step one, first by following proportioning, aluminum sulfate, potassium sulfate and water being carried out dispensing, wherein: aluminum sulfate is 20 ~ 25wt%, potassium sulfate is 10 ~ 13wt%, and all the other are water；Again normal pressure, 80 ~ 100 DEG C and 150～500r/min speed conditions under stirring 1 ~ 2h prepare potassium alum crystalline mother solution I；

Step 2, at normal pressure or when vacuum is 0.02 ~ 0.05MPa, by step one prepare potassium alum crystalline mother solution I evaporation and concentration to solution density be 1.25 ~ 1.35g/mL, prepare potassium alum crystalline mother solution II；

Step 3, normal pressure, 80 ~ 100 DEG C and 150～500r/min speed conditions under, in the potassium alum crystalline mother solution II that step 2 prepares, add crystal seed, insulated and stirred 0.5 ~ 1h, prepare suspended magma；

Step 4, under the speed conditions of normal pressure and 150～500r/min, the suspended magma that step 3 prepares is cooled to 25 ~ 35 DEG C with the speed of 1～10 DEG C/h, then filters, washing, dry；Prepare the mean diameter potassium alum crystal more than 1.5mm, filtrate and washings and return step one recycled。

Described crystal seed is Potassium aluminum sulfate dodecahydrate crystal, and Seed charge is 0.1～5wt% of potassium alum crystalline product gross mass。

Claims (2)

1. the preparation method of a potassium alum, it is characterised in that specifically complete according to the following steps:

Step one, first by following proportioning, aluminum sulfate, potassium sulfate and water being carried out dispensing, wherein: aluminum sulfate is 20 ~ 25wt%, potassium sulfate is 10 ~ 13wt%, and all the other are water；Again normal pressure, 80 ~ 100 DEG C and 150～500r/min speed conditions under stirring 1 ~ 2h prepare potassium alum crystalline mother solution I；

Step 2, at normal pressure or when vacuum is 0.02 ~ 0.05MPa, by step one prepare potassium alum crystalline mother solution I evaporation and concentration to solution density be 1.25 ~ 1.35g/mL, prepare potassium alum crystalline mother solution II；

Step 3, normal pressure, 80 ~ 100 DEG C and 150～500r/min speed conditions under, in the potassium alum crystalline mother solution II that step 2 prepares, add crystal seed, insulated and stirred 0.5 ~ 1h, prepare suspended magma；

Step 4, under the speed conditions of normal pressure and 150～500r/min, the suspended magma that step 3 prepares is cooled to 25 ~ 35 DEG C with the speed of 1～10 DEG C/h, then filters, washing, dry；Prepare the potassium alum crystal that mean diameter is big, filtrate and washings and return step one recycled。

2. the preparation method of potassium alum according to claim 1, it is characterised in that described crystal seed is Potassium aluminum sulfate dodecahydrate crystal, Seed charge is 0.1～5wt% of potassium alum crystalline product gross mass。