CN215828370U - System for magnesium process of iron and steel smelting doctor solution coproduction ammonium sulfate - Google Patents

Abstract

A system for coproducing ammonium sulfate from iron and steel smelting magnesium process desulfurization liquid, belonging to the technical field of industrial wastewater treatment. From technical magnesium hydroxide Mg (OH)₂High-purity magnesite MgO, industrial magnesia MgO product preparation subsystem and light magnesium carbonate 4MgCO₃·Mg(OH)₂·4H₂Preparation system of O-active magnesium oxide MgO product and agricultural ammonium sulfate (NH)₄)₂SO₄And a product preparation subsystem. The method has the advantages that the desulfurizing liquid magnesium sulfate is converted into high-quality magnesium salt and agricultural ammonium sulfate products with large market demands by introducing ammonia water and ammonium bicarbonate, waste materials are changed into valuable substances, the advantages of waste gas, waste hot air and electric energy are further utilized, the product cost is greatly reduced, the problem of industrial sewage treatment in the prior art is thoroughly solved, environmental hazards are eliminated, and meanwhile, a 'new industrial sewage treatment industrialization' label with high return rate is provided for resource utilization of the desulfurizing liquid of magnesium desulphurization.

Description

System for magnesium process of iron and steel smelting doctor solution coproduction ammonium sulfate

Technical Field

The invention belongs to the technical field of industrial wastewater treatment, and particularly relates to a system for co-producing ammonium sulfate from desulfurization liquid by a flue gas magnesium method.

Background

The flue gas magnesium desulphurization is widely applied to various industrial fields, especially plays an important role in the steel smelting industry, such as sintering, blast furnace and other flue gas treatment, and the desulphurization effect reaches the technical level of ultralow emission.

Magnesium desulfurization, the main component of the final desulfurization product is magnesium sulfate aqueous solution, and the existing treatment method is to obtain magnesium sulfate heptahydrate by evaporation, cooling and crystallization. The magnesium sulfate is affected by denitration and desulfurization due to the complex components of the flue gas, the desulfurization solution contains VOC, soluble ammonium salt, soluble sodium salt and other trace components besides the main component magnesium sulfate, and the impurities are mixed into the crystallization product magnesium sulfate heptahydrate, so that the problems of product difference, low main component content and the like are caused, and the magnesium sulfate can only be used as a cheap agricultural product. The balance sale can be realized just by enterprises with producing areas close to the using areas, and the steel enterprises in remote areas have no way to realize the balance disposal on the spot and only can store the soluble solid wastes which become extremely harmful.

Obviously, the magnesium desulphurization can be well developed only by converting the desulphurization product magnesium sulfate waste liquid into a product with high added value and wide market demand.

In 12.24.2020, the applicant submits a patent application, patent acceptance number 202011642624.5, to the patent office of the national intellectual property office in terms of a system and a method for efficiently utilizing flue gas desulfurization resources by a magnesium process.

The invention aims to provide a system and a method for high-efficiency resource production of flue gas desulfurization by a magnesium method, which realize zero discharge of waste residues and wastewater by converting all harmful substance elements in a magnesium method desulfurization system into chemical products with high quality, high benefit and large market demand.

The method is based on flue gas magnesium desulphurization, takes the resource transfer of desulphurization solution magnesium sulfate to high added value as a main line, adopts pure water and condensed water as system water, removes crude stone impurities from the desulphurization completion solution through purification, eliminates COD influence through aeration, and obtains a magnesium hydroxide target and an ammonium sulfate transition solution through intervening double decomposition and ammonia absorption reaction of ammonia gas and the desulphurization solution magnesium sulfate; the intervention lime and ammonium sulfate transition solution are subjected to ammonia distillation precipitation reaction to obtain calcium sulfate target substances and ammonia gas; the light magnesium carbonate target and the ammonia consumption of the system are obtained by the ammonia evaporation and heat transformation reaction of the interposed ammonium bicarbonate and the magnesium hydroxide filter material; all the evaporated ammonia gas returns to repeat ammonia absorption reaction with the desulfurization solution magnesium sulfate; all the condensed water produced by the system returns to the system for filtering material washing and dissolving ammonium bicarbonate; washing liquid 1 for washing magnesium hydroxide is used for lime digestion; the washing liquid 2 for washing calcium sulfate is used for dissolving magnesium oxide (light calcined powder); filtering the filtrate of the magnesium carbonate filter material to dissolve ammonium bicarbonate; the process is repeated, and the desulfurization liquid magnesium sulfate formed by steaming out and absorbing ammonia is continuously converted into high-content, high-performance and high-value chemical products such as magnesium hydroxide, gypsum, light magnesium carbonate and the like. When the clean flue gas is discharged after reaching the standard, all substances entering the system are extracted from waste to valuable and from inferior to superior in an orderly resource manner, the discharge of waste residues, waste water and zero is fundamentally realized, the large problems of solid waste disposal and soluble salt pollution to underground water in the prior art are thoroughly solved, and the mark of 'emerging desulfurization chemical industry' with high return rate for desulfurization of the coal-fired flue gas is eliminated while the environmental hazard is eliminated.

The invention well achieves the aim of resource conversion of the desulfurization solution, obtains products with high added value and commercial value and market demand, and also practically realizes the discharge of waste residue, waste water and zero and simultaneously thoroughly solves the problem of solid waste disposal, but has the defects in the United states: firstly, the defects of low-fuel value blast furnace gas, waste hot air and waste hot water in the steel industry are not clearly highlighted, and secondly, one of the output products is gypsum, although the quality of the gypsum is excellent, the market of high-quality gypsum is concerned in the industry, and once the sale of the gypsum is blocked, the solid waste disposal is difficult.

Therefore, it is necessary to further develop ideas on the basis of the technical advantages, fully utilize steel or other industries with waste heat energy resources to highlight own advantages, better and more simply recycle the desulfurized liquid magnesium sulfate waste liquid, and make the flue gas magnesium method desulfurization resource efficient utilization system and method more perfectly and more newly.

Disclosure of Invention

The invention aims to provide a system for coproducing ammonium sulfate from a desulfurization solution obtained by a magnesium smelting method of steel, which is characterized in that after the desulfurization solution magnesium sulfate is purified by a purification and impurity removal unit, part of magnesium sulfate is separated into magnesium hydroxide, high-purity magnesite and industrial magnesium oxide products by a concentration adjustment ammonia precipitation unit; by precipitating MgCO₃The rest magnesium sulfate is converted into light magnesium carbonate and active magnesium oxide; converting the ammonium sulfate solution generated and enriched in the process into an agricultural ammonium sulfate product through a multi-effect evaporation concentration unit; all substance elements in the desulfurization solution are converted into chemical products with high quality, high benefit and large market demand by drying and calcining the intermediate products with the help of blast furnace gas and electric energy advantages, and zero discharge of waste residues and waste water is realized.

In order to achieve the aim, the invention provides a system for coproducing ammonium sulfate from iron and steel smelting magnesium process desulfurization liquid, which is formed by sequentially associating a plurality of chemical engineering units according to a chemical engineering reaction process, and is characterized in that:

p1: sequentially comprises a purification and impurity removal unit, a concentration adjustment ammonia precipitation unit, a filtering and washing 1 unit, a drying unit, a crushing and packaging 1 unit, a high-temperature electric melting unit, a calcining unit and a crushing and packaging 2 unit to form industrial magnesium hydroxide Mg (OH)₂-high purity magnesite MgO-industrial magnesia MgO product preparation subsystem;

p2: sequentially precipitating MgCO₃The unit, the filtration washing 2 unit, the heat conversion unit, the filtration unit, the drying and crushing unit and the low-temperature electric calcination unit form light magnesium carbonate 4MgCO₃·Mg(OH)₂·4H₂A preparation subsystem of O-active magnesium oxide MgO product;

p3: sequentially comprises a scrubbing, concentrating, desulfurizing and dedusting unit, a filtering and purifying unit, a multi-effect evaporation and concentration unit and a crystallization and separation unit to form agricultural ammonium sulfate (NH)₄)₂SO₄A product preparation subsystem;

p4: the purifying and impurity removing unit consists of a desulfurizing liquid MgSO₄Feed inlet and cleaned MgSO₄A solution outlet which is communicated with the inlet of the concentration adjustment ammonia precipitation unit; the concentration adjustment ammonia precipitation unit is also provided with a solution condensed water inlet, a washing liquid 1 inlet, an ammonia water inlet and a slurry outlet communicated with the slurry inlet of the filtration washing 1 unit; the unit for filtering and washing 1 is also provided with a pure water inlet, a filtrate 1 outlet, a washing liquid 1 outlet and a magnesium hydroxide filter material outlet, wherein the filtrate 1 outlet and the precipitated MgCO are connected₃The feed inlet of the unit filtrate 1 is communicated with the discharge outlet of the washing liquid 1 and the precipitated MgCO₃The feed inlet of the unit washing liquid 1 is communicated, and the discharge outlet of the magnesium hydroxide filter material is communicated with the feed inlet of the drying unit; the drying unit is provided with a dry flue gas outlet and three dry material discharge ports besides a combustion gas injection port, the dry flue gas outlet is communicated with a flue gas press-in port of the scrubbing concentration desulfurization dust removal unit, the three dry material discharge ports are respectively communicated with a feed port of the crushing package 1 unit, a feed port of the high-temperature electric melting unit and a feed port of the calcining unit, a discharge port of the calcining unit is communicated with a feed port of the crushing package 2 unit, and the crushing package 1 unit is provided with industrial magnesium hydroxide Mg (OH)₂A product discharge port, wherein the high-temperature electric melting unit is provided with a high-purity magnesia MgO product discharge port, and the crushing package 2 unit is provided with an industrial magnesia MgO product discharge port; precipitation of MgCO₃The unit is provided with ammonium bicarbonate NH₄HCO₃A feed inlet, an ammonia water filling opening, a feed inlet for filtrate 1, a washing liquid 2 and a slurry discharge opening, wherein the slurry discharge opening is communicated with a feed inlet of a filtering and washing unit 2The unit of filtering and washing 2 is also provided with a solution condensation water pressure inlet, a washing liquid 2 discharge port, a filtrate 2 discharge port and a filter material discharge port, wherein the washing liquid 2 discharge port and the precipitated MgCO₃The feed inlet of the unit washing liquid 2 is communicated, the discharge outlet of the filtrate 2 is communicated with the injection inlet of the solution spray pipe of the washing gas concentration desulfurization dust removal unit, and the discharge outlet of the filter material is communicated with the feed inlet of the heat conversion unit; the heat conversion unit is also provided with a pure water pressure inlet, a steam inlet, a filtrate 3 inlet, a condensed water outlet and a slurry outlet, wherein the slurry outlet is communicated with a slurry inlet of the filtering unit, and the filtrate 3 inlet is communicated with a filtrate 3 outlet of the filtering unit; the discharge port of the filtering unit is communicated with the feed port of the drying and crushing unit, and the drying and crushing unit is also provided with a combustion gas injection port, a drying flue gas outlet, a dried material discharge port and light magnesium carbonate 4MgCO₃·Mg(OH)₂·4H₂The discharge port of the dried material of the O product is communicated with the material inlet of the low-temperature electric calcining unit, and the low-temperature electric calcining unit is also provided with an active magnesium oxide MgO product outlet; the scrubbing concentration desulfurization dust removal unit is provided with a solution spray pipe inlet, a dry calcination flue gas inlet, a waste hot air (waste hot air) inlet, a clean flue gas exhaust outlet and a scrubbing liquid discharge port, ammonium sulfate solution entering from a solution spray pipe injection port reversely exchanges with higher-temperature sulfur-containing dust-containing flue gas entering from a dry calcination flue gas inlet at the lower part of the solution spray pipe in a spraying mode to finish a desulfurization scrubbing dust concentration task, waste hot air entering from the waste hot air inlet also reversely exchanges heat with the ammonium sulfate solution sprayed from top to bottom, evaporation of moisture in the ammonium sulfate solution is promoted to the maximum extent and the ammonium sulfate solution is discharged from the exhaust outlet along with the clean flue gas, so that the ammonium sulfate solution is primarily concentrated, the scrubbing liquid discharge port of the scrubbing liquid discharge port is communicated with a filtering and purifying unit feed port, the primarily concentrated ammonium sulfate solution is pressed into the filtering and purifying unit, and the purified ammonium sulfate solution is discharged from the filtering and purifying unit discharge port, the concentrated solution enters the multi-effect evaporation and concentration unit from a feeding hole of the multi-effect evaporation and concentration unit communicated with the multi-effect evaporation and concentration unit, and the multi-effect evaporation and concentration unit is also provided with a steam inlet, a condensed water (pure water) discharging hole, a solution condensed water discharging hole, a concentrated solution discharging hole communicated with the feeding hole of the crystallization separation unit and a mother solution returning hole communicated with a mother solution discharging hole of the concentration separation unit;the crystallization separation unit is also provided with agricultural ammonium sulfate (NH)₄)₂SO₄A product outlet; the steam condensed water (pure water) outlet of the heat transfer unit and the multi-effect evaporation concentration unit is communicated with the pure water press-in ports of the filtration washing unit 1 and the heat transfer unit, and the solution condensed water (solution evaporation condensed water) outlet of the multi-effect evaporation concentration unit is respectively communicated with the solution condensed water inlet of the concentration adjustment ammonia precipitation unit and the solution condensed water pressure inlet of the filtration washing unit 2.

The invention relates to a system for coproducing ammonium sulfate from a steel smelting magnesium process desulfurization solution, wherein a purification and impurity removal unit in a P1 subsystem is not labeled with aerated magnesium sulfite and COD influence elimination, and the method is a conventional operation considering that the flue gas desulfurization unit utilizes waste heat air (waste hot air) to carry out the operation and carries out primary slag and stone screening operation.

The invention relates to a system for coproducing ammonium sulfate from a steel smelting magnesium process desulfurization solution, wherein a waste hot air inlet is arranged on a scrubbing, concentrating, desulfurizing and dedusting unit in a P3 subsystem, and the system is considered to have additional advantages outside the system.

The invention relates to a system for coproducing ammonium sulfate from desulfurization liquid in a magnesium smelting process of steel, wherein a purification and impurity removal unit in a P1 subsystem does not mark what impurities are filtered and removed, because the impurities are mostly solid powder such as raw stone slag materials with small particles, and the like, the impurities are nontoxic and tasteless, the content and the quantity of the impurities are very little compared with the treatment capacity of the system, and the impurities can be accumulated at regular intervals to be used as landfill or returned to a fly ash utilization system for utilization. Similarly, the situation of the fly ash filtered by the filtering and impurity removing unit of the P3 subsystem is the same as that of the fly ash filtered by the filtering and impurity removing unit, and the fly ash can be treated as above.

The invention relates to a system for coproducing ammonium sulfate from desulfurization liquid in a magnesium smelting process of steel, wherein no circulating washing gas is marked in a washing gas concentration desulfurization dust removal unit in a P3 subsystem, and the circulating washing gas is not excluded in the invention, which belongs to the technical common practice, and the required circulating times can be comprehensively determined according to the solution concentration, the combustion value of combustion gas, the flue gas temperature, the flue gas flow and the suitable evaporation efficiency.

The combustion gas and the blast furnace gas are the same low-combustion value gas, and the use of gas resources such as coke oven gas and the like is not excluded.

The ammonia water of the invention is generally concentrated ammonia water.

The ammonium bicarbonate of the present invention broadly refers to agricultural ammonium bicarbonate.

The invention relates to a system for coproducing ammonium sulfate from a steel smelting magnesium process desulfurization solution, wherein each unit of the system can be decomposed or combined as necessary, and the decomposition and combination follow the common chemical reaction principle and do not form creative breakthroughs for the invention.

The invention provides a system for coproducing ammonium sulfate from a magnesium-method desulfurization solution in steel smelting, which is convenient to understand and is based on the following main principles and key points:

1. controlling the input amount of ammonia (ammonia water) and MgSO₄Solution preparation Mg (OH)₂Intermediate product (product)

Slowly adding ammonia water NH into the purified magnesium sulfate solution with the adjusted concentration under the stirring action₄OH, and controlling the dosage of ammonia water to be less than 70 percent of magnesium sulfate in the magnesium sulfate solution to be converted into magnesium hydroxide precipitate and (NH)₄)₂SO₄Solution:

ammonia precipitation reaction: MgSO (MgSO)₄+2NH₄OH＝Mg(OH)₂↓+(NH₄)₂SO₄

This ammonia precipitation reaction precipitates Mg (OH)₂The conversion rate of the reaction (2) is not high, and when it exceeds 70%, the chemical reaction tends to be in equilibrium.

The main reason for the control conversion lower than 70% is to facilitate the adjustment of the structural proportions of the product according to the invention according to market demand and profit objectives.

The reaction product of the ammonia precipitation was filtered and washed with pure water to obtain pure Mg (OH)₂The filtrate 1 is a mixed solution of ammonium sulfate containing a large amount of magnesium sulfate solution, and the washing liquid 1 is a solution containing a small amount of magnesium sulfate and ammonium sulfate.

2. Drying the magnesium hydroxide filter material to remove free water to obtain an industrial magnesium oxide product.

3. Calcining magnesium hydroxide at low temperature to lose one molecular water to obtain industrial magnesium oxide product.

4. The magnesium hydroxide loses one molecular water by electric melting calcination at the high temperature of more than or equal to 1500 ℃ to obtain the high-purity magnesite clinker.

5. The ammonium bicarbonate reacts with the ammonia water and the magnesium sulfate solution to precipitate magnesium carbonate

When the filtrate 1 and ammonia (especially concentrated ammonia) are added to the dissolved ammonium bicarbonate, a more pronounced alkaline environment is formed, magnesium carbonate MgCO is precipitated₃Chemical reaction:

MgCO₃precipitation reaction: MgSO (MgSO)₄+NH₄HCO₃+NH₄OH＝MgCO₃↓+(NH₄)₂SO₄+H₂O

The MgCO3 precipitate is a relatively low-solubility product, which favors magnesium sulfate (MgSO)₄Tends to be complete, hence MgSO₄The magnesium in (1) is converted into magnesium hydroxide Mg (OH) through two ammonia precipitations₂And magnesium carbonate MgCO₃，MgSO₄Sulfate radical SO in (1)₄ ^2-The ammonia is completely converted into ammonium sulfate (NH) through two times of ammonia precipitation₄)₂SO₄And (3) solution.

6. Intermediate product for preparing light magnesium carbonate by thermal transformation

MgCO of magnesium carbonate precipitated from ammonium bicarbonate, magnesium sulfate and ammonia water₃Unstable and easy to transform into other crystal forms, especially when heated, according to the following reaction:

and (3) hot transformation:

after the reaction is finished, magnesium carbonate MgCO with unstable solid structure₃Basic magnesium carbonate (light magnesium carbonate) 4MgCO directly converted into another solid structure₃·Mg(OH)₂·4H₂And O, filtering to obtain a light magnesium carbonate filter material intermediate product.

7. The intermediate product of the light magnesium carbonate filter material is dried at low temperature to lose free water to obtain an intermediate product of light magnesium carbonate, and then the intermediate product is crushed to obtain light magnesium carbonate 4MgCO₃·Mg(OH)₂·4H₂And (4) O products.

8. The light magnesium carbonate intermediate product can be used for preparing an active magnesium oxide (light magnesium oxide) MgO product through low-temperature electric calcination, and the magnesium oxide has high activity, large apparent specific volume and excellent performance.

4MgCO₃·Mg(OH)₂·4H₂O＝5MgO+4CO₂↑+5H₂O

9. The ammonium sulfate solution filtrate 2 is used for gas washing, desulfurization and dust removal of dry and calcined flue gas, is subjected to heat exchange and concentration by the flue gas with higher temperature and waste heat air, the evaporated moisture is discharged along with the clean flue gas, the primarily concentrated ammonium sulfate solution is subjected to multi-effect evaporation, and ammonium sulfate (NH) is obtained through crystallization and separation₄)₂SO₄And (5) producing the product.

The invention relates to a system for coproducing ammonium sulfate from a magnesium-method desulfurization solution in steel smelting, which takes the magnesium-method desulfurization solution as a raw material, taking the desulfurization solution magnesium sulfate (magnesium sulfate desulfurization solution) to be transferred to high-added-value resources as a main line, adopting steam condensate water to replace pure water to wash a magnesium hydroxide filter material and adjust the solid content of heat transfer, washing the magnesium carbonate filter material by using solution condensate water obtained by multi-effect evaporation of an ammonium sulfate solution, carrying out ammonia precipitation reaction on the purified magnesium sulfate solution and intervened ammonia gas to obtain a magnesium hydroxide intermediate product and an ammonium sulfate transition solution, drying, crushing and packaging the magnesium hydroxide washed by the pure water (steam condensate water) to obtain an industrial magnesium hydroxide product, and also obtaining high-purity magnesite sand in a high-added-value large market through electric energy high-temperature electric smelting, meanwhile, the dried magnesium hydroxide can be calcined, crushed and packaged by blast furnace gas to obtain industrial magnesium oxide; secondly, the magnesium sulfate solution which is not completely converted into magnesium hydroxide is continuously subjected to precipitation reaction and thermal transformation reaction with intervening ammonium bicarbonate and ammonia water to obtain a light magnesium carbonate intermediate product and an ammonium sulfate transition solution, the filtered light magnesium carbonate (also called magnesium carbonate) filter material is dried and crushed by blast furnace gas to obtain a light magnesium carbonate product, and the light magnesium carbonate is calcined at low temperature by electric energy to obtain an active magnesium oxide product; thirdly, the ammonium sulfate transition solution contains a small amount of active magnesium carbonate components, has the functions of washing gas and desulfurizing, is used for washing gas, concentrating, desulfurizing and dedusting dry flue gas and calcined flue gas, and ensures that the ammonium sulfate solution is concentrated after the clean flue gas is emptied; fourthly, the purified ammonium sulfate solution is subjected to multi-effect evaporation concentration and cooling crystallization separation to obtain an agricultural ammonium sulfate product; and fifthly, returning steam condensate water (also called pure water) of the heat conversion and multi-effect evaporation concentration unit to the filtering and washing unit of the system to wash filter cakes, and returning mother liquor of the crystallization separation unit to the multi-effect evaporation concentration unit for repeated evaporation to form a closed system and a process system.

Therefore, the magnesium sulfate waste liquid entering the system is converted into magnesium hydroxide and magnesium carbonate intermediate products with higher purity and capable of being washed by pure water respectively, and can be deeply converted into industrial magnesium hydroxide, industrial magnesium oxide, high-purity magnesite, light magnesium carbonate products and active magnesium oxide with extremely high purity, excellent performance and extremely low cost through combustion gas (blast furnace gas) drying and calcining, and electric energy high-temperature calcining and electric energy low-temperature calcining; secondly, the main component of ammonium sulfate (denitration escape ammonia desulfurization product) is continuously enriched with newly generated ammonium sulfate along with the process, and finally, the ammonium sulfate product is obtained through concentration and crystallization; the desulfurization solution also contains trace components such as partial soluble nitrates (sodium, iron), chlorides and the like, and the trace components enter the ammonium sulfate product along with the crystallization of the ammonium sulfate, so that the product quality requirement of the agricultural ammonium sulfate is not influenced due to the low comprehensive content of the trace components. Therefore, the desulfurization liquid magnesium sulfate waste liquid is completely extracted by orderly recycling waste wastes, the emission of waste residues, waste water and zero is realized fundamentally, on the basis of reasonably utilizing the advantages of blast furnace gas, hot air and hot water, sulfate ions in the desulfurization liquid are converted into agricultural ammonium sulfate fertilizer required by large market, and the confusion and interference of gypsum byproduct formation to the desulfurization industry are successfully avoided.

Compared with the prior art, the invention has the beneficial effects that:

the invention relates to a system for coproducing ammonium sulfate from desulfurization liquid in a steel smelting magnesium method, which utilizes the chemical balance characteristic of magnesium hydroxide precipitated by ammonia water and partial magnesium sulfate, controls the ammonia input amount to effectively adjust the product structure of a primary magnesium salt, precipitates the rest magnesium sulfate into magnesium carbonate by using ammonium bicarbonate to assist concentrated ammonia water and carries out heat transformation to obtain a light magnesium carbonate product, completely converts the magnesium sulfate into high-purity magnesite, light magnesium carbonate and light magnesium oxide series products and agricultural ammonium sulfate fertilizer, avoids potential soluble solid waste hidden danger of the magnesium sulfate heptahydrate while avoiding solid waste of gypsum, greatly reduces the product cost by virtue of waste air and blast furnace gas, realizes the ultra-low emission target, contributes a waste liquid treatment mode with simple process, waste recycling and convenient industrial development, and is suitable for related enterprises struggling on an environmental protection pressure life line, undoubtedly, the medicine is a good prescription and wonderful plan for taking one dose to death and revive, and has important practical significance and long-term development significance.

Drawings

The invention is further described below with reference to the accompanying drawings and embodiments, it is obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings can be obtained by those skilled in the art without inventive effort.

FIG. 1 is a schematic view of a system for co-producing ammonium sulfate from a magnesium desulphurization solution in steel smelting.

As can be seen from FIG. 1, the system of the present invention is clear and can be used for intuitively and clearly explaining the content of the present invention.

FIG. 2 is a schematic diagram of system characteristic identification of the joint production of ammonium sulfate from the magnesium desulphurization solution in steel smelting.

As can be seen from fig. 2, the system of the present invention has clear technical features, and can accurately explain the contents of the invention and the contents of the claims.

In FIG. 2

1-purifying and impurity removing unit, 2-concentration adjusting ammonia precipitation unit, 3-filtering and washing 1 unit,

4-drying unit, 5-crushing and packaging 1 unit, 6-high temperature electric melting unit,

7-calcination unit, 8-crushing packaging 2 unit, 9-precipitation of MgCO₃The unit cell is a unit cell, which is composed of a plurality of unit cells,

10-filtration washing 2 unit, 11-heat conversion unit, 12-filtration unit,

13-drying and crushing unit, 14-low temperature electric calcining unit, 15-scrubbing, concentrating, desulfurizing and dedusting unit,

16-filtration purification unit, 17-multiple-effect evaporation concentration unit and 18-crystallization separation unit.

Detailed Description

Example 1: as can be seen from figure 2, the invention provides a system for coproducing ammonium sulfate from a magnesium-method desulfurization solution in steel smelting, which is formed by sequentially associating a plurality of chemical engineering units according to a chemical reaction process, and is characterized in that:

p1: comprises a purification and impurity removal unit 1, a concentration adjustment ammonia precipitation unit 2, a filtration and washing unit 13, a drying unit 4, a crushing and packaging unit 15, a high-temperature electric melting unit 6, a calcining unit 7 and a crushing and packaging unit 2 8 which are sequentially arranged to form industrial magnesium hydroxide Mg (OH)₂-high purity magnesite MgO-industrial magnesia MgO product preparation subsystem;

p2: sequentially precipitating MgCO₃The unit 9, the filtering and washing 2 unit 10, the heat conversion unit 11, the filtering unit 12, the drying and crushing unit 13 and the low-temperature electric calcining unit 14 form light magnesium carbonate 4MgCO₃·Mg(OH)₂·4H₂A preparation subsystem of O-active magnesium oxide MgO product;

p3: sequentially comprises a scrubbing, concentrating, desulfurizing and dedusting unit 15, a filtering and purifying unit 16, a multi-effect evaporation and concentration unit 17 and a crystallization and separation unit 18 to form agricultural ammonium sulfate (NH)₄)₂SO₄A product preparation subsystem;

p4: the purification and impurity removal unit 1 is composed of desulfurization solution MgSO₄Feed inlet and cleaned MgSO₄A solution outlet which is communicated with the inlet of the concentration adjustment ammonia precipitation unit 2; the concentration adjustment ammonia precipitation unit 2 is also provided with a solution condensed water inlet, a washing liquid 1 inlet, an ammonia water inlet and a slurry outlet communicated with the slurry inlet of the unit 3 of the filtration washing 1; the unit 3 of the filtering and washing 1 is also provided with a pure water inlet and filtrate1 outlet, 1 outlet for washing liquid and 1 outlet for magnesium hydroxide filter material, and 1 outlet for filtrate and precipitated MgCO₃The feed inlet of the unit 9 filtrate 1 is communicated with the discharge outlet of the washing liquid 1 and the precipitated MgCO₃The feeding hole of the washing liquid 1 of the unit 9 is communicated, and the discharging hole of the magnesium hydroxide filter material is communicated with the feeding hole of the drying unit 4; the drying unit 4 is provided with a dry flue gas outlet and three dry material outlets besides a combustion gas injection port, the dry flue gas outlet is communicated with a flue gas press-in port of a scrubbing, concentrating, desulfurizing and dedusting unit 15, the three dry material outlets are respectively communicated with a feed port of a unit 5 of the crushing and packaging unit 1, a feed port of a high-temperature electric melting unit 6 and a feed port of a calcining unit 7, a discharge port of the calcining unit 7 is communicated with a feed port of a unit 8 of the crushing and packaging unit 2, and the unit 5 of the crushing and packaging unit 1 is provided with industrial magnesium hydroxide Mg (OH)₂A product discharge port, wherein the high-temperature electric melting unit 6 is provided with a high-purity magnesia MgO product discharge port, and the crushing package 2 unit 8 is provided with an industrial magnesia MgO product discharge port; precipitation of MgCO₃The unit 9 being provided with ammonium bicarbonate NH₄HCO₃A feed inlet, an ammonia water filling port, a filtrate 1, a washing liquid 2 feed inlet and a slurry discharge port, wherein the slurry discharge port is communicated with a feed inlet of a filtering and washing 2 unit 10, the filtering and washing 2 unit 10 is also provided with a solution condensation water pressure inlet, a washing liquid 2 discharge port, a filtrate 2 discharge port and a filter material discharge port, and the washing liquid 2 discharge port is communicated with precipitated MgCO₃The feeding hole of washing liquid 2 of the unit 9 is communicated, the discharging hole of filtrate 2 is communicated with the feeding hole of a solution spray pipe of the washing gas concentration desulfurization dust removal unit 15, and the discharging hole of filter material is communicated with the feeding hole of the heat conversion unit 11; the heat conversion unit 11 is also provided with a pure water pressure inlet, a steam inlet, a filtrate 3 inlet, a condensed water outlet and a slurry outlet, wherein the slurry outlet is communicated with the slurry inlet of the filtering unit 12, and the filtrate 3 inlet is communicated with the filtrate 3 outlet of the filtering unit 12; the discharge port of the filtering unit 12 is communicated with the feed port of the drying and crushing unit 13, and the drying and crushing unit 13 is also provided with a combustion gas injection port, a drying flue gas outlet, a dried material discharge port and light magnesium carbonate 4MgCO₃·Mg(OH)₂·4H₂An O product outlet, a dry material outlet of which is communicated with a material inlet of the low-temperature electric calcining unit 14, and the low-temperature electric calcining unit 14 is also provided with activityA magnesium oxide MgO product outlet; the scrubbing concentration desulfurization dust removal unit 15 is provided with a solution spray pipe inlet, a dry calcination flue gas inlet, a waste heat air (waste heat air) inlet, a clean flue gas exhaust outlet and a scrubbing liquid discharge port, ammonium sulfate solution entering from a solution spray pipe injection port is reversely exchanged with higher temperature sulfur-containing dust-containing flue gas entering from a dry calcination flue gas inlet at the lower part of the solution spray pipe in a spraying mode to finish the desulfurization scrubbing dust concentration task, waste heat air entering from the waste heat air inlet also reversely exchanges heat with the ammonium sulfate solution sprayed from top to bottom, thereby promoting the evaporation of water in the ammonium sulfate solution to the maximum degree and discharging the water from the exhaust outlet along with the clean flue gas to primarily concentrate the ammonium sulfate solution, the scrubbing liquid discharge port of the scrubbing liquid discharge port is communicated with the feed port of the filtering and purifying unit 16 and presses the primarily concentrated ammonium sulfate solution into the filtering and purifying unit 16, and the purified ammonium sulfate solution is led out from the discharge port of the filtering and purifying unit 16, the concentrated solution enters the multi-effect evaporation and concentration unit 17 from a feed inlet of the multi-effect evaporation and concentration unit 17 communicated with the multi-effect evaporation and concentration unit, the multi-effect evaporation and concentration unit 17 is also provided with a steam inlet, a condensed water (pure water) discharge outlet, a concentrated solution discharge outlet communicated with a feed inlet of the crystallization separation unit 18 and a mother solution return outlet communicated with a mother solution discharge outlet of the crystallization separation unit 18; the crystallization separation unit 18 is also provided with agricultural ammonium sulfate (NH)₄)₂SO₄A product outlet; the steam condensate (pure water) discharge ports of the heat transfer unit 11 and the multiple-effect evaporation concentration unit 17 are communicated with the pure water inlet ports of the filtration washing 1 unit 3 and the heat transfer unit 11, and the solution condensate (solution evaporation condensate) discharge port of the multiple-effect evaporation concentration unit 17 is respectively communicated with the solution condensate water inlet port of the concentration adjustment ammonia precipitation unit 2 and the solution condensate water pressure inlet port of the filtration washing 2 unit 10.

When the system is used:

purifying the desulfurization liquid magnesium sulfate in a purification and impurity removal unit, adding a purified magnesium sulfate solution into a closed concentration adjustment ammonia precipitation unit, diluting the magnesium sulfate concentration to a proper concentration by using a washing solution 1 for washing a magnesium hydroxide filter material and solution condensate water, introducing concentrated ammonia water to react with the diluted magnesium sulfate, and converting part of the magnesium sulfate into a magnesium hydroxide precipitate and an ammonium sulfate transition solution (remaining unconverted part of the magnesium sulfate); the slurry after the reaction is processed by a filtering and washing unit operation, and pure magnesium hydroxide filter material intermediate product, filtrate 1 and washing liquid 1 are separated for later use;

the pure magnesium hydroxide filter material intermediate product is respectively dried by a drying unit, calcined at high temperature by a high-temperature electric melting unit and calcined at low temperature by a calcining unit to jointly produce the industrial magnesium hydroxide Mg (OH)₂High-purity magnesite MgO and industrial magnesia MgO products;

in precipitating MgCO₃Ammonium bicarbonate NH is added into the unit₄HCO₃Ammonium bicarbonate NH is prepared by adopting washing liquid 1, washing liquid 2 and filtrate 1₄HCO₃Dissolving and adjusting proper concentration, adding strong ammonia water to generate precipitation reaction of magnesium carbonate, converting magnesium sulfate into magnesium carbonate (magnesium carbonate) and ammonium sulfate transition solution, filtering and washing slurry after reaction by 2 units, and separating out pure magnesium carbonate filter material intermediate product, ammonium sulfate filtrate 2 with high purity and washing liquid 2 for later use;

adjusting the solid content of the intermediate product of the magnesium carbonate filter material in a heat conversion unit by using pure water and filtrate 3 for filtering light magnesium carbonate filter material, introducing steam for heating to implement heat conversion reaction of the magnesium carbonate filter material, and converting the magnesium carbonate into amorphous alkali type magnesium carbonate (light magnesium carbonate) 4MgCO₃·Mg(OH)₂·4H₂Depositing O, solid-liquid separating in filtering unit to obtain intermediate product of light magnesium carbonate filter material, low-temp drying the intermediate product with combustion gas, introducing the dried fume into gas washing, concentrating, desulfurizing and dusting unit, exhausting clean fume, and pulverizing to obtain light magnesium carbonate 4MgCO with high content, activity and specific volume₃·Mg(OH)₂·4H₂The product O, the light magnesium carbonate after drying is electrocauterized at low temperature to obtain active magnesium oxide, and the task of a subsystem for preparing the light magnesium carbonate product is completed;

the ammonium sulfate filtrate 2 is used as a washing gas desulfurization dust removing agent to carry out reverse washing gas desulfurization dust removal on the flue gas from a drying unit, a calcining unit and a drying and crushing unit in a washing gas concentration desulfurization dust removing unit, meanwhile, the ammonium sulfate solution can be used for carrying out heat exchange with waste heat air with a certain temperature, the flue gas with higher temperature and the waste heat air have the effect of heating and concentrating the ammonium sulfate, part of water is discharged along with clean flue gas, the ammonium sulfate solution subjected to purification, concentration and heating is purified by a filtering and purifying unit and further concentrated by a multi-effect evaporation and concentration unit, and finally, after crystallization and separation, mother liquor returns to the multi-effect evaporation unit to be crystallized into an ammonium sulfate product, thereby completing the task of preparing a subsystem from the agricultural ammonium sulfate product;

the process water balance is maintained by adopting steam condensate water, solution condensate water and washing liquor, and the steam condensate water is firstly used for replacing pure water to wash and dilute the materials with high requirement on the purity of the final product, namely washing the magnesium hydroxide filter material and diluting the magnesium carbonate filter material; secondly, washing the filter material with higher requirement on the purity of the intermediate product by using relatively pure solution condensate water, namely washing the magnesium carbonate filter material; thirdly, the concentration of the slurry is adjusted by using a washing liquid which does not cause side reaction, namely, the concentration of the magnesium sulfate solution is adjusted by using a washing liquid 1 for washing the magnesium hydroxide filter cake, and the concentration of the ammonium bicarbonate is adjusted by returning a washing liquid 2 for washing the magnesium carbonate filter material; the originally excessive waste liquid of the system is utilized in a balanced way.

Thus, the perfect operation of the system is completed.

Claims (1)

1. The utility model provides a system for magnesium process doctor solution coproduction ammonium sulfate is smelted to steel, is formed according to chemical industry reaction process relevance in proper order by a plurality of chemical industry units, its characterized in that:

p1: comprises a purification and impurity removal unit (1), a concentration adjustment ammonia precipitation unit (2), a filtration and washing 1 unit (3), a drying unit (4), a crushing and packaging 1 unit (5), a high-temperature electric melting unit (6), a calcining unit (7) and a crushing and packaging 2 unit (8) in sequence to form industrial magnesium hydroxide Mg (OH)₂-high purity magnesite MgO-industrial magnesia MgO product preparation subsystem;

p2: sequentially precipitating MgCO₃The unit (9), the filtering and washing 2 unit (10), the heat conversion unit (11), the filtering unit (12), the drying and crushing unit (13) and the low-temperature electric calcining unit (14) form light magnesium carbonate 4MgCO₃·Mg(OH)₂·4H₂A preparation subsystem of O-active magnesium oxide MgO product;

p3: sequentially comprises a scrubbing, concentrating, desulfurizing and dedusting unit (15) and a filtering and purifying unit(16) Agricultural ammonium sulfate (NH) consisting of a multi-effect evaporation and concentration unit (17) and a crystallization and separation unit (18)₄)₂SO₄A product preparation subsystem;

p4: the purification and impurity removal unit (1) is composed of a desulfurization solution MgSO₄Feed inlet and cleaned MgSO₄A solution discharge port which is communicated with a feed port of the concentration adjustment ammonia precipitation unit (2); the concentration adjustment ammonia precipitation unit (2) is also provided with a solution condensed water inlet, a washing liquid 1 inlet, an ammonia water inlet and a slurry outlet communicated with the slurry inlet of the filtering and washing unit 1 (3); the unit (3) of the filtering and washing 1 is also provided with a pure water inlet, a filtrate 1 outlet, a washing liquid 1 outlet and a magnesium hydroxide filter material outlet, wherein the filtrate 1 outlet and the precipitated MgCO are arranged₃The feed inlet of the filtrate 1 of the unit (9) is communicated with the discharge outlet of the washing liquid 1 of the unit (9) and the precipitated MgCO₃The feeding hole of the washing liquid 1 of the unit (9) is communicated, and the discharging hole of the magnesium hydroxide filter material is communicated with the feeding hole of the drying unit (4); the drying unit (4) is provided with a dry flue gas outlet and three dry material discharge ports besides a combustion gas injection port, the dry flue gas outlet is communicated with a flue gas press-in port of the scrubbing concentration desulfurization dust removal unit (15), the three dry material discharge ports are respectively communicated with a feed port of the crushing package 1 unit (5), a feed port of the high-temperature electric melting unit (6) and a feed port of the calcining unit (7), a discharge port of the calcining unit (7) is communicated with a feed port of the crushing package 2 unit (8), and the crushing package 1 unit (5) is provided with industrial magnesium hydroxide Mg (OH)₂A product discharge port, wherein the high-temperature electric melting unit (6) is provided with a high-purity magnesia MgO product discharge port, and the crushing package 2 unit (8) is provided with an industrial magnesia MgO product discharge port; precipitation of MgCO₃The unit (9) is provided with ammonium bicarbonate NH₄HCO₃A feed inlet, an ammonia water filling port, a filtrate 1, a washing liquid 2 feed inlet and a slurry discharge outlet, wherein the slurry discharge outlet is communicated with a feed inlet of a filtering and washing 2 unit (10), the filtering and washing 2 unit (10) is also provided with a solution condensation water pressure inlet, a washing liquid 2 discharge outlet, a filtrate 2 discharge outlet and a filter material discharge outlet, and the washing liquid 2 discharge outlet and the precipitated MgCO are communicated with each other₃The inlet of washing liquid 2 of the unit (9) is communicated, the outlet of the filtrate 2 is communicated with the inlet of a solution spray pipe of the washing gas concentration desulfurization dust removal unit (15), and the outlet of the filter material is communicated with a heat conversion unitThe feed inlets of the element (11) are communicated; the heat conversion unit (11) is also provided with a pure water pressure inlet, a steam inlet, a filtrate 3 inlet, a condensed water outlet and a slurry outlet, wherein the slurry outlet is communicated with a slurry inlet of the filtering unit (12), and the filtrate 3 inlet is communicated with a filtrate 3 outlet of the filtering unit (12); the discharge hole of the filtering unit (12) is communicated with the feed hole of the drying and crushing unit (13), and the drying and crushing unit (13) is also provided with a combustion gas injection port, a drying flue gas outlet, a dried material discharge hole and light magnesium carbonate 4MgCO₃·Mg(OH)₂·4H₂An O product outlet, wherein a dry material discharge port of the O product outlet is communicated with a material inlet of the low-temperature electric calcining unit (14), and the low-temperature electric calcining unit (14) is also provided with an active magnesium oxide MgO product outlet; the scrubbing concentration desulfurization dust removal unit (15) is provided with a solution spray pipe inlet, a dry calcining flue gas inlet, a waste heat air inlet, a clean flue gas exhaust outlet and a scrubbing liquid discharge port, ammonium sulfate solution entering from a solution spray pipe injection port reversely exchanges with higher-temperature sulfur-containing dust-containing flue gas entering from a dry calcining flue gas inlet at the lower part of the solution spray pipe in a spraying mode to finish a desulfurization scrubbing concentration task, waste heat air entering from the waste heat air inlet also reversely exchanges heat with the ammonium sulfate solution sprayed from top to bottom, evaporation of moisture in the ammonium sulfate solution is promoted to the maximum extent and is discharged from the exhaust outlet along with the clean flue gas, so that the ammonium sulfate solution is primarily concentrated, the scrubbing liquid discharge port of the scrubbing liquid discharge port is communicated with a filtration and purification unit (16), the primarily concentrated ammonium sulfate solution is pressed into the filtration and purification unit (16), and the purified ammonium sulfate solution is led out from the discharge port of the filtration and purification unit (16), the concentrated solution enters the multi-effect evaporation and concentration unit (17) from a feed inlet of the multi-effect evaporation and concentration unit (17) communicated with the multi-effect evaporation and concentration unit, the multi-effect evaporation and concentration unit (17) is also provided with a steam inlet, a condensed water discharge port, a solution condensed water discharge port, a concentrated solution discharge port communicated with the feed inlet of the crystallization separation unit (18) and a mother solution return port communicated with a mother solution discharge port of the crystallization separation unit (18); the crystallization separation unit (18) is also provided with agricultural ammonium sulfate (NH)₄)₂SO₄A product outlet; the steam condensate water outlet of the heat transfer unit (11) and the multi-effect evaporation concentration unit (17) is communicated with the pure water inlet of the filtration washing unit 1 and the heat transfer unit, and the multi-effect evaporation concentration unitThe solution condensed water outlet of the concentration unit (17) is respectively communicated with the solution condensed water inlet of the concentration adjustment ammonia precipitation unit (2) and the solution condensed water pressure inlet of the filtration washing unit (10).

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