CN1256242A

CN1256242A - Production process of boric acid and magnesium carbonate from boromagnesite

Info

Publication number: CN1256242A
Application number: CN 99126276
Authority: CN
Inventors: 孙新华; 欧秀芹
Original assignee: Tianjin Chemical Research & Design Inst Ministry Of Chemical Industry
Current assignee: Tianjin Chemical Research & Design Inst Ministry Of Chemical Industry
Priority date: 1999-12-23
Filing date: 1999-12-23
Publication date: 2000-06-14
Anticipated expiration: 2019-12-23
Also published as: CN1108987C

Abstract

The present invention relates to the technology of processing boromagnesite. The production process includes ammonium salt solution decomposition of boromagnesite powder to prepare boric acid solution, cooling the boric acid solution to separate boric acid crystal, reaction of the recovered boric acid mother liquor with the carbonated ammonia water prepared from recovered ammonia water to obtain magnesium carbonate, and returing the reacted mother liquor for reuse in the decomposition of boromagnesite. The production process has the advantages of comprehensive utilization of boromagnesite, no waste effluent and low production cost.

Description

Production method for preparing boric acid and co-producing magnesium carbonate from boron-magnesium ore

The invention relates to the technical field of boron ore processing.

At present, the domestic method for producing boric acid from boron-magnesium ore mainly adopts sulfuric acid to decompose boron-magnesium ore, and after the boric acid is prepared, the boric acid and magnesium sulfate in mother liquor reach a common saturation point. The mother liquor is treated in two ways, namely, the mother liquor is discharged to seriously pollute the environment; and secondly, magnesium sulfate is recovered, but the magnesium sulfate has boric acid, so that the product quality cannot reach the product standard, and the benefit is poor.

The process seeks a processing method of the boron-magnesium ore, which can solve the problem of processing the mother liquor in the process and can comprehensively utilize the effective components in the boron-magnesium ore.

The invention is realized by the following modes:

the process for preparing boric acid and co-producing magnesium carbonate from ascharite comprises double decomposition reaction of ammonium salt and ascharite, cooling, crystallizing, and separating to obtain boric acid; recycling the separated boric acid mother liquor; the ammonia released by the reaction is modulated into carbonized ammonia water to react with the separated boric acid mother liquor to prepare magnesium carbonate. After separating magnesium carbonate, the synthetic mother liquor returns to the double decomposition reaction of the boron-magnesium ore for recycling. The specific process comprises the following steps:

1. decomposition of boron-magnesium ores

Dissolving ammonium saltHeating the solution and the boron-magnesium ore powder under stirring until the mixture is nearly boiled for reaction, filtering, cooling and crystallizing the filtrate, and separating out boric acid, wherein the solution is boric acid mother liquor. Absorbing the ammonia gas discharged in the double decomposition reaction with water to prepare ammonia water, and adding ammonium bicarbonate or CO into the ammonia water₂And the carbonized ammonia water is prepared for synthesizing magnesium carbonate.

Taking the reaction of ammonium sulfate with tibetan reservoir boromagnesite as an example, the reaction formula is as follows:

ammonium sulfate, ammonium nitrate or ammonium chloride is generally used as the ammonium salt.

The boromagnesite is mineral powder with Kushui boromagnesite, column boromagnesite and polyhydrated boromagnesite as main components. The process has good effect by adopting the tibetan boron-magnesium ore.

The reaction temperature is controlled to be about 10 ℃ of the boiling point of the solution.

The concentration of the ammonium salt in the above reaction is between 0.8mol/l and 3 mol/l.

The molar ratio of the ammonium salt to the ascharite in the reaction is NH₄ ⁺/Mg²⁺1.5-4.0: 1, and the larger the ratio is, the higher the decomposition rate of the boron ore is.

2. Synthesis of magnesium carbonate

Synthesizing magnesium carbonate from the boric acid mother liquor and carbonized ammonia water, and returning the mother liquor for separating magnesium carbonate to the decomposition process of the boromagnesite, taking the decomposition of the boromagnesite by ammonium sulfate as an example:

mg in boric acid mother liquor in the reaction²⁺The concentration of (b) is 0.5-2 mol/L.

NH in carbonated ammonia water in the above reaction₃H₂O/NH₄HCO₃(mol) ═ 0-3.0: 1, amount NH₄HCO₃/Mg²⁺＝1-2.5∶1。

The reaction temperature in the above reaction is controlled at 40-90 ℃.

The synthetic precipitate is washed, separated, dried and crushed to obtain magnesium carbonate product, and magnesium carbonate can also be calcined to obtain magnesium oxide product. The synthesis mother liquor returns to the metathesis reaction.

The process has the advantages that the process can produce boric acid products which meet the GB538-90 standard, and can produce basic magnesium carbonate products which meet the GB1612-88 standard. The boron-magnesium ore is comprehensively utilized, the solution in the whole process flow is recycled, and the problems of waste liquid discharge and environmental pollution are avoided. The consumption of raw materials is low, and theoretically, other raw materials except the raw material of the boron-magnesium ore are not consumed. Low production cost and considerable economic benefit.

The process is further illustrated by the following examples, but the invention is not limited to these examples.

Example one

170m of water and 18g of ammonium sulfate were charged into a double decomposition reactor equipped with a stirrer, and after heating and dissolving, 30g of boron-magnesium ore powder (containing B) was added₂O₃Percent: 30.97%, MgO: 15.94%), boiling, releasing ammonia gas, reaction under slight boiling for 3 hr, filtering and washing to obtain 180ml solution containing B₂O₃：49.25g/L，MgO：22.16g/L。

Example two

Adding 100ml water and 9.4g ammonium chloride into a double decomposition reactor with stirring, heating to dissolve, adding 20g boron magnesium ore powder, heating to boil, reacting for 0.5 hr, filtering, and washingWashing to obtain 204ml of solution containing B₂O₃：29.27g/L，MgO：14.14g/L。

EXAMPLE III

Adding 100ml water and 14g ammonium nitrate into a double decomposition reactor with stirring, heating to dissolve, adding 20g boron magnesium ore powder, heating to boil, reacting for 2 hr under slightly boiling condition, filtering, and washing to obtain solution containing B220 ml₂O₃：25.43g/L，MgO：12.25g/L。

Example four

Adding 300ml of water and 45g of ammonium sulfate into a double decomposition reactor with stirring, heating to dissolve, adding 70g of boron-magnesium ore powder, heating to boil, reacting for 2 hours under the condition of maintaining micro boiling, filtering and washing to obtain 300ml of solution, and crystallizing to obtain 17 g of boric acid. And 300ml of boric acid mother liquor is obtained.

EXAMPLE five

The boric acid mother liquor of example four (containing B)₂O₃: 28.28g/L, MgO: 31.72g/L) with ammonia concentration of 120g/L, NH₃H₂O/NH₄HCO₃110ml of 1.75: 1 carbonized ammonia water was reacted at 75 ℃ for 1 hour, filtered, washed and dried to obtain 18g of magnesium carbonate, and 420ml of synthetic mother liquor was obtained.

EXAMPLE six

Example five contained MgO: 5.51g/L, B₂O₃：22.34g/L，(NH₄)₂SO₄: 121.85g/L of synthesis mother liquor, putting into a decomposition reactor with stirring, adding 70g of boron magnesium ore, reacting for 2 hours under boiling to obtain 350ml of boric acid solution, cooling and crystallizing to obtain 32g of boric acid, adding the boric acid mother liquor into the synthesis reactor, adding 145ml of carbonized ammonia water, wherein the carbonized ammonia water comprises: NH (NH)₃H₂O/NH₄HCO₃＝1.75∶1，NH₃Reacting at 75 deg.C for 1hr to obtain magnesium carbonate 20.5g with concentration of 120g/L, and 457ml synthetic mother liquor (containing MgO: 5.63g/L, B)₂O₃：21.36g/L，(NH₄)₂SO₄：117.57g/L)。

Claims

1. A method for preparing boric acid and co-producing magnesium carbonate from ascharite is characterized in that:

1.1, carrying out double decomposition reaction on ammonium salt and boron magnesium ore, cooling, crystallizing and separating to prepare boric acid;

1.2 the ammonia released from the double decomposition reaction is modulated into carbonized ammonia water to react with the separated boric acid mother liquor,

preparing magnesium carbonate;

1.3 separating the ammonium salt mother liquor after magnesium carbonate, returning to the double decomposition reaction of the boron-magnesium ore for recycling.

2. A method according to claim 1, characterized in that: the concentration of the ammonium salt is NH₄ ⁺The content of the active carbon is 0.8-3.0 mol/L.

3. A method according to claim 1, characterized in that: the ammonium salt is ammonium sulfate, ammonium nitrate or ammonium chloride.

4. A method according to claim 1, characterized in that: the ludwigite is mineral powder with ludwigite, troglite and polyhydrated ludwigite as main components.

5. A method according to claim 1, characterized in that: the reaction temperature is around the boiling point of the solution.

6. A method according to claims 1-5, characterized in that: the molar ratio of the ammonium salt to the ascharite is NH₄ ⁺/Mg²⁺＝1.5-4.0∶1。