KR20010010581A - Process for preparing potassium sulfate and ferrous chloride from ferrous sulfate - Google Patents

Abstract

PURPOSE: A preparation method of potassium sulfate(KSO4) and ferrous chloride(FeCl2) from ferrous sulfate(FeSO47H2O) produced in titanium factory is provided. Also, HCl and reduced Fe are obtained by reacting the above FeCl2 with H2 gas. The resultant KSO4 and reduced Fe are applicable to fertilizers and powder metallurgy or reductants, respectively. CONSTITUTION: KSO4 and FeCl2 are obtained by mixing FeSO47H2O with KCl in an equivalent ratio of 1.05:1 or 1.1:1 and then grinding it to a size of more than 100mesh, followed by adding methanol or ethanol and stirring at 40-50deg.C for 2-3hrs. Reduced Fe and HCl are also obtained by reacting formed FeCl2 with H2 at about 600deg.C like these: FeCl2 + H2 -->Fe + 2HCl.

Description

Process for producing potassium sulfate and iron chloride from iron sulfate {PROCESS FOR PREPARING POTASSIUM SULFATE AND FERROUS CHLORIDE FROM FERROUS SULFATE}

The present invention relates to a process for producing potassium sulfate and iron chloride from iron sulfate. More particularly, the present invention relates to a method for preparing potassium sulfate and iron chloride by reacting iron sulfate with potassium chloride.

Iron sulphate is produced in large quantities as waste in pickling processes in titanium plants or steel and steel companies. Such iron sulfate is highly toxic, causing intestinal pain, abdominal pain, diarrhea, and the like, when inhaled in large quantities, causing vomiting, bleeding, peripheral neuropathy, etc., but a method of efficiently treating such a large amount of iron sulfate generated Since it has not been developed yet, titanium plants or steel companies that produce iron sulphate as a by-product can not process iron sulphate and shorten or stop the operation of the plant itself. Even if iron sulphate can be treated, it is not economical, and the unit cost of pickling of a desired titanium or steel company has increased significantly.

Iron sulphate is a product such as the state of the hexahydrate (FeSO ₄ ?? 7H ₂ O) and ferric sulphate [Fe ₂ (SO ₄ ) ₃ ] such as magnetic iron oxide (Fe ₂ O ₃ ) and iron polysulfate as a plant wastewater treatment agent. Although m [Fe ₂ (SO ₄ ) ₃ ] is commercially available, ferrous sulfate produced as a by-product from a titanium company, etc., is too large, and there is no alternative other than the method of disposal due to its low purity.

The present inventors have diligently researched to solve the above problems, and it is possible to produce ferric chloride and potassium sulfate by metathesis of ferrous sulfate and potassium chloride, and to purify iron chloride with high purity as needed to produce hydrochloric acid and reduced iron. Discovered and completed the present invention.

That is, the present invention provides a method for producing iron chloride and potassium sulfate from ferrous sulfate.

The present invention also provides a method of producing hydrochloric acid and reduced iron by bringing hydrogen chloride into contact with hydrogen gas at a high temperature.

Hereinafter, the configuration and operation of the present invention will be described in detail.

First, ferrous sulfate and potassium chloride are mixed in an equivalent ratio, which is ground to at least 100 mesh, preferably at least 200 mesh. If the particle diameter of these compound powders is large, the reaction surface area may be small, so that the reaction time may be long, or unreacted substances may be generated.

The pulverized product is added to methanol or ethanol and reacted for about 30 minutes to 4 hours, usually 2 to 3 hours while stirring at 40 to 50 ° C. This reaction time greatly depends on the particle size of the reactants. After the reaction, the mixture is filtered to recover potassium sulfate, and the iron chloride dissolved in the filtrate is separated. The use of alcohol as a solvent here takes into account the solubility of each compound. When the reaction is reacted in an aqueous solution, some metathesis occurs, but not completely. As a reason, iron sulfate does not react insoluble in alcohol, but in aqueous solution, the produced potassium sulfate and iron chloride cause a reverse reaction again, and thus high purity potassium sulfate and iron chloride cannot be obtained.

Therefore, when ferrous sulfate and potassium chloride are reacted in alcohol, ferrous sulfate does not react insoluble to alcohol, and potassium chloride is almost insoluble in alcohol (solubility: 1 g of potassium chloride is dissolved in 250 ml of alcohol). In other words, the two compounds react in the dispersed state in alcohol.

On the other hand, ferrous sulfate and potassium chloride react in alcohol to form potassium sulfate and iron chloride, potassium sulfate is insoluble in alcohol, but iron chloride is very easily dissolved in water or alcohol, so potassium sulfate precipitates after reaction and iron chloride Is present in solution. It was filtered to separate potassium sulfate, and the filtrate containing iron chloride was concentrated by evaporation, iron chloride was recovered in a solid phase, alcohol was recovered by cooling, and the water contained in the recovered alcohol (formed by hydrate of ferrous sulfate). Water) can recover high purity alcohol by separating water according to the method of 1999 Patent Application No. 3390 of the present inventors.

The potassium sulfate obtained in this way contains almost no chlorine component, but when chlorine is present, it is purified so that the chlorine component is 1.5% or less. Such potassium sulfate is widely used as a carry fertilizer. Therefore, potassium sulfate can be usefully used as a tobacco fertilizer or a plant growth fertilizer.

On the other hand, after the iron chloride obtained in the reaction is brought to an anhydrous state, it is brought into contact with hydrogen at a high temperature, for example, about 600 ° C. This hydrogenation reaction is a known reaction. This is represented by the following reaction scheme.

FeCl ₂ + H ₂ → Fe + 2HCl

Iron obtained in this reaction is reduced iron, and about 20,000 to 30,000 tons are imported annually as powder metallurgy and reducing agent, and hydrochloric acid is commercially sold at about 1 million tons per year. Therefore, potassium sulfate, reduced iron and hydrochloric acid obtained by the method of the present invention are all expensive or are important components in the chemical industry.

In this reaction, it is preferable to react ferrous sulfate and potassium chloride in an equivalent ratio. However, in order to avoid the presence of chlorine content in the obtained potassium sulfate, the amount of ferrous sulfate is slightly equivalent to that of potassium chloride, for example, from 1.05: 1 to It is preferable to react in the equivalence ratio of 1.1: 1.

EXAMPLE

Hereinafter, an Example is given and this invention is demonstrated concretely. However, the present invention is not limited by these examples.

Example 1

283.3 g of ferrous sulfate hepatate and 148 g of potassium chloride were mixed, and then ground by a ball mill to obtain 150 mesh or more. 500 g of methanol was added thereto and stirred at about 45 ° C. for 3 hours. Filtration recovered potassium sulfate, which was washed twice with 100 cc of methanol and dried to obtain 174 g of potassium sulfate. Furthermore, the filtrate obtained above and the washing | cleaning liquid were combined, and the combined filtrate was evaporated and 126 g of iron chlorides were obtained.

As a result of analyzing the chlorine content of the obtained potassium sulfate, the chlorine content was 0.8%.

Example 2

The same procedure as in Example 1 was carried out except that ethanol was used instead of methanol. As a result, 172 g of potassium sulfate and 127 g of iron chloride were obtained. In addition, the chlorine content of the obtained potassium sulfate was 0.95%.

This shows almost the same result as Example 1, and is within the experimental error range.

Example 3

Ferrous Sulfate 253.5 g of 7 hydrated salt and 151.9 g of potassium chloride were mixed, pulverized to 300 mesh, placed in 500 ml of 96% ethanol, and stirred at 50 ° C for 30 minutes for reaction. The obtained potassium sulfate was 176.6 g (yield: about 98.5%), iron chloride was 124.1 g (yield: about 98%), and the content of potassium sulfate was 1.2%.

Example 4

As a result of the same reaction in Example 3, except that 75% ethanol was used, 174 g of potassium sulfate and 126 g of iron chloride were obtained. As a result of analysis, potassium sulfate had a chlorine content of 1.5%, and iron chloride had a sulfate group of 1000. ppm was present.

Comparative Example 1

The same operation was followed in Example 3 except using 60% ethanol. As a result, 148.4 g of potassium sulfate and 104.3 g of iron chloride were obtained. As a result of analyzing these, potassium sulfate had a chlorine content of 5.5% and iron sulfate content of 2.2%.

Thus, the potassium sulfate obtained was not suitable for direct use as a fertilizer.

Example 5

12.6 g of iron chloride obtained in the above example was placed in a crucible boat of a sealed Pyrex glass tube and maintained at 600 ± 20 ° C. while passing hydrogen gas. The exiting gas was adsorbed to 200 cc of water. After 1.5 hours, the gas discharged was tested with a wet litmus paper, and the reaction was confirmed not to exhibit acidity. When the crucible in the reaction tube was taken out and the component of iron (reduced iron) was confirmed, the amount of iron obtained was 5.5 g. As a result of analyzing this, chlorine component did not remain but all were reduced iron.

In addition, the water passed through the exhaust gas was analyzed and converted into hydrochloric acid absorbing theoretical chlorine.

As described above, according to the present invention, ferrous sulfate, which has been a problem of conventional environmental pollution and the like by easily converting potassium sulfate, which is useful as a fertilizer, and iron chloride by reacting ferrous sulfate generated in a titanium factory or the like with potassium chloride, has been described. In addition to being able to be easily treated, the present invention has yielded a compound that is economically useful. Accordingly, the present invention provides a revolutionary effective invention that solves the problem of ferrous sulfate.

Claims (6)

Pulverizing ferrous sulfate and potassium chloride followed by addition in ethanol or methanol and reacting at room temperature to about 50 ° C. The method according to claim 1, wherein when ferrous sulfate is the hexate, ethanol or methanol used is 96% or more. The method according to claim 1, wherein the mixing ratio of ferrous sulfate and potassium chloride is an equivalent ratio. The method according to claim 1, wherein the amount of ferrous sulfate in the mixing ratio of ferrous sulfate and potassium chloride is an equivalent ratio of 1.05: 1 to 1.1: 1, which is an equivalent ratio slightly larger than potassium chloride. A method for producing reduced iron and hydrochloric acid by catalytic hydrogenation of iron chloride as a reaction product of claim 1. The method of claim 5, wherein the catalytic hydrogen reaction is carried out at about 600 ° C. 7.