Combination preparation method for anhydrous magnesium chloride and potassium sulphate

Abstract

The present invention provides a combined preparation method of a waterless magnesium chloride and a potassium sulfate and meanwhile produces a hydrochloride. The technic proposal is that a hexahydrated magnesium chloride (MgCl2 question mark 6H2O) is dehydrated to a dihydrated magnesium chloride. A hydrogen chloride dry gas is dried and dehydrated to a waterless magnesium chloride in a fluidizedbed. The second step is that after a heat transfer, a dehydrated hydrogen chloride tail gas enters into a drying tower of a concentrated sulfuric acid and an oleum and the tail gas is dehydrated. Thedried hydrogen chloride is recycled. After absorbing the water, a dilute sulfuric acid enters into a sulfate production device to absorb a sulfur trioxide again and becomes the concentrated sulfuric acid. The redundant dilute sulfuric acid enters into a Mannheim device to produce a potassium sulfate and the produced hydrogen chloride produces the hydrochloride after being cleansed. The technologyproducing the waterless magnesium chloride, provided by the present invention, has the advantages of low cost, good quality, high purity quotient, low energy consumption and little environmental pollution.

Description

Technical field

[0001] The invention relates to a method for preparing chemicals, in particular to a method that uses magnesium chloride hexahydrate (MgCl 2 ·6H 2 O) The process of preparing anhydrous magnesium chloride and simultaneously producing potassium sulfate and hydrochloric acid. Background technique

[0002] my country is a country with large sea-lake salt resources, and magnesium in sea-lake salt is the resource second only to sodium in reserves. Take Qaidam Salt Lake as an example, the reserves of magnesium salt are as high as 4.81 billion tons. For a long time, the utilization of sea-lake salt resources has mainly focused on salt production or potassium extraction. During the process of potassium extraction, the average by-product is about 10 tons of magnesium chloride for every 1 ton of potassium chloride produced. Due to insufficient attention in production technology and deep processing, the production process The large amount of high-magnesium brine (magnesium c...

Examples

Embodiment

[0022] Example: Dry the hydrogen chloride tail gas after producing anhydrous magnesium chloride, with a moisture content of 5% (V / V), and pass through a two-stage sulfuric acid drying tower (the first stage is 8% SO3 fuming sulfuric acid, the second The grade is 98% concentrated sulfuric acid), and the moisture content in the hydrogen chloride gas after drying is less than 0.1% (V / V). The dried hydrogen chloride gas is used to enter the fluidized bed to dry magnesium chloride dihydrate, the drying temperature is gradually increased from 200°C to 290°C within 30 minutes, and heating is continued at this temperature for 10 minutes to obtain anhydrous magnesium chloride product. The obtained anhydrous magnesium chloride product. The content of magnesium chloride is 96.20%, the water content is 0.21%, the magnesium oxide is 0.27%, and the rest are other salt impurities. The above products fully meet the requirements of electrolytic magnesium;

[0023] The dehydrated hydrogen chlorid...

Technical field

[0001] The invention relates to a method for preparing chemicals, in particular to a method that uses magnesium chloride hexahydrate (MgCl 2 ·6H 2 O) The process of preparing anhydrous magnesium chloride and simultaneously producing potassium sulfate and hydrochloric acid. Background technique

[0002] my country is a country with large sea-lake salt resources, and magnesium in sea-lake salt is the resource second only to sodium in reserves. Take Qaidam Salt Lake as an example, the reserves of magnesium salt are as high as 4.81 billion tons. For a long time, the utilization of sea-lake salt resources has mainly focused on salt production or potassium extraction. During the process of potassium extraction, the average by-product is about 10 tons of magnesium chloride for every 1 ton of potassium chloride produced. Due to insufficient attention in production technology and deep processing, the production process The large amount of high-magnesium brine (magnesium c...

Examples

Embodiment

[0022] Example: Dry the hydrogen chloride tail gas after producing anhydrous magnesium chloride, with a moisture content of 5% (V / V), and pass through a two-stage sulfuric acid drying tower (the first stage is 8% SO3 fuming sulfuric acid, the second The grade is 98% concentrated sulfuric acid), and the moisture content in the hydrogen chloride gas after drying is less than 0.1% (V / V). The dried hydrogen chloride gas is used to enter the fluidized bed to dry magnesium chloride dihydrate, the drying temperature is gradually increased from 200°C to 290°C within 30 minutes, and heating is continued at this temperature for 10 minutes to obtain anhydrous magnesium chloride product. The obtained anhydrous magnesium chloride product. The content of magnesium chloride is 96.20%, the water content is 0.21%, the magnesium oxide is 0.27%, and the rest are other salt impurities. The above products fully meet the requirements of electrolytic magnesium;

[0023] The dehydrated hydrogen chlorid...