CN112441621A

CN112441621A - Comprehensive utilization method of manganese-rich slag

Info

Publication number: CN112441621A
Application number: CN202011334219.7A
Authority: CN
Inventors: 张弦; 吴珍; 李宇; 常世界; 晁自胜
Original assignee: Ordos Institute of Technology
Current assignee: Ordos Institute of Technology
Priority date: 2020-11-24
Filing date: 2020-11-24
Publication date: 2021-03-05

Abstract

The invention discloses a comprehensive utilization method of manganese-rich slag, which comprises the following steps: (1) acid leaching to prepare leaching solution and silicon slag; (2) removing aluminum from the leaching solution; (3) removing iron from the leaching solution after removing aluminum; (4) leaching solution after iron removal is used for manganese precipitation; (5) preparation of Mn by manganese carbonate oxidizing roasting₂O₃；(6)Mn₂O₃Disproportionating and oxidizing to obtain active manganese dioxide; (7) the white carbon black or the 4A molecular sieve is prepared by recycling the silica slag. The invention realizes the comprehensive utilization of main elements of manganese, silicon and aluminum in the manganese-rich slag, develops industrial products of 4A molecular sieve, active manganese dioxide, ammonium alum and red iron oxide with higher added value, and opens up a new way for the utilization of the manganese-rich slag; meanwhile, the purposes of fully utilizing resources and reducing pollution can be achieved.

Description

Comprehensive utilization method of manganese-rich slag

The technical field is as follows:

the invention relates to the technical field of comprehensive utilization of manganese-rich slag, in particular to a comprehensive utilization method of manganese-rich slag.

Background art:

the manganese-rich slag has a plurality of sources, and is mainly a byproduct after ironmaking and steelmaking of ferromanganese ore. The manganese-rich slag obtained in the way generally requires low contents of iron and phosphorus and high contents of manganese and silicon, and also generally contains partial elements such as aluminum, magnesium, calcium and the like.

According to preliminary statistics, the total output of manganese-rich slag in China is 20-25 ten thousand tons. Because of different conditions of raw materials used by various manufacturers, the manganese-rich slag has larger component difference, and the manganese content is lower than 35 percent and higher than 40 percent.

The manganese-rich slag is traditionally utilized mainly for producing silicon-manganese alloy and manganese-iron alloy. The current iron and steel industry is not prosperous and causes the sale of the manganese-rich slag to be limited to a certain extent, so the conditions of single usage of the manganese-rich slag and relatively low added value of products must be changed, a new product taking the manganese-rich slag as a raw material is developed, the resource utilization rate of the manganese-rich slag is improved, and higher economic benefit is created.

The invention content is as follows:

the invention aims to provide a comprehensive utilization method of manganese-rich slag, which has high added value of products, full utilization of resources and more economic and environment-friendly effects.

The purpose of the invention is implemented by the following technical scheme: the comprehensive utilization method of the manganese-rich slag comprises the following steps: (1) acid leaching to prepare leaching solution and silicon slag; (2) removing aluminum from the leaching solution; (3) removing iron from the leaching solution after removing aluminum; (4) leaching solution after iron removal is used for manganese precipitation; (5) preparation of Mn by manganese carbonate oxidizing roasting₂O₃；(6)Mn₂O₃Disproportionating and oxidizing to obtain active manganese dioxide; (7) preparing white carbon black or a 4A molecular sieve by recycling the silica slag; wherein，

(1) Acid leaching to prepare leaching solution and silicon slag: adopting concentrated sulfuric acid as a leaching agent, adding excessive concentrated sulfuric acid in a dropwise manner, carrying out acid leaching reaction on manganese-rich slag containing 30-50% of Mn by mass percent, and filtering and separating to obtain leaching solution and silicon slag; the self-dilution can generate heat for reaction, thereby reducing heat consumption.

The principle of acidification reaction:

2H⁺+MnO_x→Mn²⁺+H₂O+(x-1)O₂↓ (x is larger than 1 and smaller than 2)

6H⁺+Al₂O₃→2Al³⁺+3H₂O

2xH⁺+FeO_x→2(x-1)Fe³⁺+(3-2x)Fe²⁺+2H₂O (x is more than 1 and less than 1.5)

2xH⁺+MS_x→xH₂S↑+M^2x+(M is a metal)

2Fe²⁺+MnO₂+4H⁺→2Fe³⁺+Mn²⁺+H₂O

2H⁺+CaO+SO₄ ^2-→CaSO₄↓+H₂O

2H⁺+SiO₃ ^2-→H₂O+SiO₂

(2) Removing aluminum from the leaching solution: adding ammonium sulfate and ammonium carbonate into the leaching solution, controlling the pH value of the solution to be 1-3 in the reaction process, and filtering after the reaction is finished to obtain aluminum ammonium sulfate crystals and the leaching solution after aluminum removal;

the principle of aluminum removal reaction:

Al³⁺+2SO₄ ^2-+NH⁴⁺+12H₂O→NH₄Al(SO₄)₂·12H₂o (Crystal precipitation)

Supersaturation produces ammonium aluminum sulfate crystals to precipitate most of the aluminum ions, care being taken that the added ammonium sulfate is first ground to speed up dissolution, and care not to be too fast to add ammonium bicarbonate. The control of the pH value is important, and when the pH value is too low, the ammonium ion concentration is insufficient, and the precipitation effect is poor; too high, hydroxide is easily generated, and crystal quality is affected. The pH value of the solution in the reaction process is controlled by adding ammonium carbonate, and the pH value is controlled to be 1-3, so that the filtered crude ammonium alum is put into an oven for decompression drying to obtain the crude ammonium alum product, wherein the purity of the alum is over 96 percent. The purity of the ammonium alum can reach more than 99.0 percent after one-time recrystallization.

The aluminum ammonium sulfate is mainly used for the industries of water purification, electroplating, papermaking, tanning, medicine, printing and dyeing, food and the like; also used for preparing foam extinguishing agent. The high-purity aluminum ammonium sulfate is a raw material for producing high-purity superfine alumina ceramic powder materials. The current common production method is mainly a recrystallization method, uses industrial sulfuric acid, ammonium sulfate and aluminum hydroxide as raw materials, prepares aluminum ammonium sulfate in a reaction kettle, obtains crude ammonium alum through concentration and crystallization, then adds the crude ammonium alum, deionized water and auxiliary agents in proportion in a dissolving tank, fully dissolves, performs vacuum filtration, concentrates and crystallizes filtrate to obtain semi-finished ammonium alum, then continuously dissolves the semi-finished ammonium alum, which is divided into ash, semi-finished ammonium alum and deionized water in the dissolving tank, performs vacuum filtration, concentrates and crystallizes to obtain the finished ammonium alum. The method can extract the aluminum element in the manganese-rich slag, creates conditions for preparing the active manganese dioxide by the next manganese precipitation, simultaneously prepares high-purity aluminum ammonium sulfate, increases the utilization approach of aluminum and can generate certain economic value.

(3) Removing iron from the leaching solution after aluminum removal: adding hydrogen peroxide dropwise into the leaching solution after removing aluminum until iron is completely oxidized to obtain a reddish brown solution, then adding ammonia water to adjust the pH value to 5-6, and filtering to obtain an iron mud filter cake and filtrate; the invention adopts a reverse neutralization titration method, so that the generated iron precipitate is easy to filter and has lower cost.

The iron removal reaction principle is as follows:

Fe²⁺+H₂O₂→Fe³⁺+H₂O

Fe³⁺+3OH^-→Fe(OH)₃↓

firstly, a small amount of oxydol oxidant is added into the filtrate to oxidize ferrous ions into ferric ions, and the pH value of the ferric ions during precipitation is reduced, so that the iron can be precipitated at a lower pH value without influencing manganese. The neutralizing agent is added to control the pH value to be 5-6, and then the ferric hydroxide precipitate can be obtained.

(4) Leaching solution after iron removal for manganese precipitation: slowly adding excessive ammonium carbonate into the leaching solution after iron removal to generate carbonate ions to form manganese carbonate precipitate, standing for 1h, and filtering to obtain a manganese carbonate filter cake;

the manganese precipitation reaction principle is as follows:

MnSO₄+2NH₄HCO₃→MnCO₃↓+(NH₄)₂SO₄+CO₂↑+H₂O

when the manganese is precipitated, ammonium carbonate is added, so that the pH value can be increased, and the concentration of carbonate ions can be increased, so that the manganese ions are precipitated in the form of manganese carbonate. However, it should be noted that the addition rate cannot be too fast, otherwise, other ions are easily entrained to affect the quality of the manganese carbonate.

(5) Preparation of Mn by manganese carbonate oxidizing roasting₂O₃: drying the obtained manganese carbonate filter cake, introducing oxygen for roasting at the temperature of 330-370 ℃ for 6 hours, and naturally cooling to obtain a black product Mn₂O₃；

(6)Mn₂O₃Carrying out disproportionation and oxidation to prepare active manganese dioxide: the obtained black product Mn₂O₃Adding water to make pulp and make solid content be 65%, adding concentrated sulfuric acid and NaClO₃Reacting at 80-85 deg.C for 2 hr, filtering, and washing with water until the pH of the filtrate is 4-7; drying the filter cake to obtain a product of black active manganese dioxide;

concentrated sulfuric acid and NaClO₃Can be obtained by calculation: suppose is provided with M₁Roasting the manganese carbonate to obtain M₂And g manganese oxide. If the oxide contains X mol MnO and Y mol MnO₂Then, there is the following formula:

X＝(87M₁-115M₂)/(115*87-115*71)

Y＝(115M₂-71M₁)/(115*87-115*71)

thus, the amounts of 108Xg of sulfuric acid and 61Xg of sodium chlorate can be determined in turn, generally requiring MnO₂The conversion rate is about 80%. I.e. Y ═ 4X calculated: m₂＝073M₁。

The process principle for preparing the active manganese dioxide comprises the following steps:

(1) and roasting:

2MnO₂→Mn₂O₃+1/2O₂

(2) and disproportionation:

Mn₂O₃+H₂SO₄→MnO₂+MnSO₄+H₂O

(3) oxidation (sodium chlorate as oxidant):

5MnSO₄+2NaC1O₃+4H₂O→5MnO₂+2NaHSO₄+4H₂SO₄+Cl₂↑

MnO formed in reaction (2)₂MnO being generated by reaction of activated manganese dioxide with MnO being generated in step (3)₂Is chemical manganese dioxide. In the process, by controlling proper reaction conditions, chemical manganese generated in the reaction (3) is inlaid in the activated manganese disproportionation micropores, or nucleation and growth are carried out on the surface of the activated manganese, so that the heavy transformation process is completed.

(7) Preparing white carbon black or a 4A molecular sieve by recycling silicon slag: the silica slag is used for preparing white carbon black or a 4A molecular sieve.

Specifically, in the step (1), water is firstly added into a reaction kettle, then the manganese-rich slag is added under the condition of stirring, and after the addition is finished, concentrated sulfuric acid is slowly dripped to react for 10 hours; the gas generated in the reaction process is absorbed by the aqueous solution of calcium hydroxide. The hydride of sulfur and phosphorus is generated, the smell is large, an absorption device is needed, and otherwise, a yellow solid is easily formed. The whole reaction device is sealed by adopting the aqueous solution of calcium hydroxide, and the toxic gas can be effectively absorbed by vacuumizing. 3000ml of water is added into each kilogram of manganese-rich slag, 1000ml of concentrated sulfuric acid is added into each kilogram of manganese-rich slag, the reaction temperature is controlled to be 80-95 ℃, and the mass percentage concentration of the concentrated sulfuric acid is 90-98%. The amount and concentration of concentrated sulfuric acid are critical, the acidity is too strong due to excessive concentrated sulfuric acid, the filtrate needs more alkali for neutralization, and the cost is increased; the concentrated sulfuric acid is too little, the reaction is incomplete, and the yield of manganese is low. In addition, the acid concentration is too low, and gel formation is likely to occur, making filtration difficult.

Specifically, in the step (2), the adding amount ratio of the ammonium sulfate, the ammonium carbonate and the leaching solution is 20-50g:50-60g:500 mL; a large amount of CO is generated in the reaction process₂Absorbing the gas with ammonia water to produce ammonium carbonate or ammonium bicarbonate for reuse.

Specifically, the preparation of the 4A molecular sieve by using the silica slag comprises the following steps:

(1) preparing sodium silicate: 350 g of washed and roasted silicon slag is taken, 500 g of NaOH solid is added, the mixture is uniformly stirred, then the mixture is slowly poured into 4000-5000mL of water, the mixture is rapidly stirred and heated to be boiled, and then the mixture is filtered to obtain a filter cake and a sodium silicate solution;

(2) preparing a sodium aluminate solution: dissolving 700g of sodium aluminate into 1500-2000mL of 1mol/L sodium hydroxide solution, and heating to obtain a clarified sodium aluminate solution;

an amount (0.1mol) of hydrochloric acid was titrated with the sodium silicate obtained, and 52ml of the above sodium silicate was consumed when the pH was equal to 7. The overall sodium silicate solution alkalinity was 8.85mol NaOH, assuming that all of the reacted NaOH was SiO₂Consuming Na for formation₂SiO₃Then the required mass of sodium aluminate can be calculated according to the mixture ratio.

(3) Preparing the 4A molecular sieve: pouring the prepared sodium silicate solution into sodium aluminate, stirring at a high speed for half an hour at a rotating speed of 14kr/min, then putting the sodium silicate solution in a large enamel barrel, and crystallizing in an oven at 100 ℃ for 12-24 hours to prepare the 4A molecular sieve.

The 4A molecular sieve is mainly an alkali metal aluminosilicate and can adsorb water and NH₃、H₂S, sulfur dioxide, carbon dioxide, C₂H₅OH、C₂H₆、C₂H₄Molecules with an equivalent critical diameter of no more than 4A. It is widely used for drying gas and liquid, and also can be used for refining and purifying some gas or liquid, such as argon gas. Due to the requirement of environmental protection, the trend of replacing phosphorus-containing auxiliaries with 4A molecular sieves in the washing industry appears, so that the demand of the phosphorus-containing auxiliaries is greatly increased.

Because the manganese-rich slag contains a large amount of silicon and aluminum elements, the invention prepares the silicon-aluminum elements into the 4A molecular sieve, so as to improve the utilization rate of the raw materials, solve the problems of silicon slag stacking and pollution and create certain economic value.

Specifically, the preparation of the white carbon black by using the silica slag comprises the following steps:

(1) alkali boiling of silicon slag: 350 g of washed and roasted silicon slag is taken, 500 g of NaOH solid is added, the mixture is uniformly stirred, then the mixture is slowly poured into 4000-5000mL of water, the mixture is rapidly stirred and heated to be boiled, and then the mixture is filtered to obtain a filter cake and a sodium silicate solution;

(2) heating the sodium silicate solution to 75-85 ℃, adjusting the pH value to 7-10, reacting for 40-55min, filtering, washing and drying to obtain the active white carbon black.

White carbon black is a general term for white powdery X-ray amorphous silicic acid and silicate products, mainly referring to precipitated silica, fumed silica, ultrafine silica gel and aerogel, and also including powdery synthetic aluminum silicate, calcium silicate, and the like. The white carbon black is porous material, and its composition can be SiO₂·nH₂O represents, wherein nH₂O is present in the form of surface hydroxyl groups. The white carbon black is mainly used as a reinforcing agent of rubber and a toothpaste friction agent. The superfine nano white carbon black can also be used as a coating matting agent, a thickening agent, a plastic film opening agent and the like.

The traditional method for preparing the white carbon black is a sodium silicate acidification method, which takes water glass as a raw material, and the precipitated white carbon black is obtained by reaction with acid, precipitation, filtration, washing and drying, namely SiO precipitated in a loose, finely dispersed and flocculent structure is obtained by acidification of the water glass₂And (3) powder.

The method utilizes the silicon slag separated after the manganese-rich slag is subjected to acid leaching to produce the high-performance white carbon black, and has higher industrial prospect and value.

The invention has the advantages that:

(1) the invention realizes the comprehensive utilization of main elements of manganese, silicon and aluminum in the manganese-rich slag, develops industrial products of 4A molecular sieve, active manganese dioxide, ammonium alum and red iron oxide with higher added value, and opens up a new way for the utilization of the manganese-rich slag.

(2) The method can separate manganese and silicon, develop the manganese and silicon into products with high utilization value, fully extract aluminum and iron elements in the manganese-rich slag, synthesize the products with high utilization value and reduce the generation of waste slag. The aluminum which is not leached completely in the slag can also be left in the silica slag and is formed into sodium aluminate through alkali fusion to be used as a raw material for forming the 4A molecular sieve.

(3) Meanwhile, the alkali liquor is used as a neutralizer of the acid liquor, so that the discharge of waste liquor is reduced, and the aims of environmental protection and full utilization of resources are fulfilled.

(4) The method is not only suitable for manganese ore, but also suitable for the main minerals such as ferro-silicon-aluminum and the like, can fully separate the elements such as the ferro-silicon-aluminum and the like, and can achieve the purposes of fully utilizing resources and reducing pollution.

Description of the drawings:

figure 1 is an XRD pattern of ammonium alum.

FIG. 2 is a TG-DSC of ammonium alum.

FIG. 3 is an SEM photograph of manganese dioxide.

FIG. 4 is EDS diagram of manganese dioxide.

FIG. 5 shows XRD patterns of sample of molecular sieve 4A in sample Nos. 1, 5, 7 and 9.

Figure 6 is a molecular sieve XRD pattern of lab 4A.

FIG. 7 is a graph of particle size analysis.

FIG. 8 is a 1# sample IR analysis chart.

FIG. 9 is a flow chart of the comprehensive utilization of manganese-rich slag.

The specific implementation mode is as follows:

example 1: as shown in fig. 9, the method for comprehensively utilizing the manganese-rich slag comprises the following steps: (1) acid leaching to prepare leaching solution and silicon slag; (2) removing aluminum from the leaching solution; (3) removing iron from the leaching solution after removing aluminum; (4) leaching solution after iron removal is used for manganese precipitation; (5) preparation of Mn by manganese carbonate oxidizing roasting₂O₃；(6)Mn₂O₃Disproportionating and oxidizing to obtain active manganese dioxide; (7) preparing white carbon black or a 4A molecular sieve by recycling the silica slag; wherein the content of the first and second substances,

(1) acid leaching to prepare leaching solution and silicon slag: adding water into a reaction kettle, adding manganese-rich slag under the condition of stirring, and after the addition is finished, adopting concentrated sulfuric acid as a leaching agent, slowly dropwise adding excessive concentrated sulfuric acid in a dropwise adding mode, and reacting for 10 hours. Adding 3000ml of water into each kilogram of manganese-rich slag, adding 800ml of concentrated sulfuric acid, and controlling the reaction temperature to be 80 ℃, wherein the mass percent concentration of the concentrated sulfuric acid is 98%; carrying out acid leaching reaction on the manganese-rich slag containing 34.21% of Mn by mass, and filtering and separating to obtain leaching solution and silicon slag. Meanwhile, the gas generated in the reaction process is absorbed by the aqueous solution of calcium hydroxide. The yield of each element of the manganese slag is as follows: 92% of manganese, 50% of aluminum and 83% of iron.

(2) Removing aluminum from the leaching solution: adding ammonium sulfate and ammonium carbonate into the leaching solution, controlling the pH value of the solution to be 2.25 in the reaction process, filtering after the reaction is finished to obtain aluminum ammonium sulfate crystals and the leaching solution after aluminum removal; the addition amount ratio of the ammonium sulfate, the ammonium carbonate and the leaching solution is 45g to 55g to 500 mL; a large amount of CO is generated in the reaction process₂Absorbing the gas with ammonia water to produce ammonium carbonate or ammonium bicarbonate for reuse. Precipitating 87% of aluminum in the filtrate, and obtaining high-purity aluminum ammonium sulfate. About 10% iron and 1.3% manganese are lost. And (4) putting the filtered crude ammonium alum into an oven, and drying under reduced pressure to obtain a crude ammonium alum product, wherein the purity of the alum is over 96 percent. The purity of the ammonium alum can reach more than 99.0 percent after one-time recrystallization. The product characterization is shown in fig. 1 and fig. 2.

(3) Removing iron from the leaching solution after aluminum removal: adding hydrogen peroxide dropwise into the leaching solution after removing aluminum until iron is completely oxidized to obtain a reddish brown solution, then adding ammonia water to adjust the pH value to 5.2, and filtering to obtain an iron mud filter cake and filtrate; the removal rate of iron was 98.96%, the removal rate of aluminum was 79.41%, and manganese was not substantially lost.

(4) Leaching solution after iron removal for manganese precipitation: slowly adding 100g of ammonium carbonate into 558mL of the leaching solution after iron removal to generate carbonate ions to form manganese carbonate precipitate, standing for 1h, and filtering to obtain a manganese carbonate filter cake; the manganese content in the precipitated manganese reaches 93 percent, and the filtrate does not contain Al and Fe basically.

(5) Preparation of Mn by manganese carbonate oxidizing roasting₂O₃: drying the obtained manganese carbonate filter cake, introducing oxygen to roast for 6 hours at 370 ℃, and naturally cooling to obtain a black product Mn₂O₃；

(6)Mn₂O₃Carrying out disproportionation and oxidation to prepare active manganese dioxide: will be describedThe obtained black product Mn₂O₃Adding water to make pulp and make solid content be 60%, adding concentrated sulfuric acid and NaClO₃Reacting at 80 ℃ for 2 hours, filtering and washing with water after the reaction is finished until the pH value of the filtrate is 4-7; drying the filter cake to obtain a product of black active manganese dioxide; the yield of manganese was 99.34%.

The preparation method of the 4A molecular sieve by using the silica slag comprises the following steps:

(3) preparing the 4A molecular sieve: and pouring the prepared sodium silicate solution into sodium aluminate, stirring at a high speed for half an hour at a rotating speed of 14kr/min, and crystallizing at the temperature of 100 ℃ for 12-24 hours to prepare the 4A molecular sieve.

The preparation of the white carbon black by utilizing the silica slag comprises the following steps:

(1) preparing sodium silicate: 350 g of washed and roasted silicon slag is taken, 500 g of NaOH solid is added, the mixture is uniformly stirred, then the mixture is slowly poured into 5000mL of water, the mixture is rapidly stirred and heated to be boiled, and then the mixture is filtered to obtain a filter cake and a sodium silicate solution;

(2) and heating the sodium silicate solution to 80 ℃, adjusting the pH value to 10, reacting for 40min, and filtering, washing and drying to obtain the active white carbon black.

First, test example:

the composition analysis of the manganese-rich slag raw material for the test is shown in Table 1

TABLE 1 analysis of manganese-rich slag raw material composition (% by mass)

Serial number	Mn	Al₂O₃	SiO₂	Fe	MgO	CaO	P
									1	32.16	15.29	31.78	2.26	1.54	1.75	0.02
2	35.01	14.46	30.82	1.67	1.63	1.84	0.02
								3	35.45	14.33	32.81	1.76	1.18	1.72	0.02
Mean value	34.21	14.69	31.8	1.90	1.45	1.77	0.02

1. Acid leaching test

1#, 2# and 3# samples are firstly added with a certain amount of water into a 10L reaction kettle, and then 1Kg of manganese-rich slag solid is added under the condition of stirring. And slowly dripping concentrated sulfuric acid with the mass percentage concentration of 98 percent after the feeding is finished. The adding speed of the concentrated sulfuric acid is controlled, otherwise, the temperature is easily overhigh, the solution is overheated, and certain danger is caused. After the charging is finished, setting a proper temperature for reaction for a period of time, and filtering while the mixture is hot.

In addition, the hydride of sulfur and phosphorus is generated, the odor is large, an absorption device is needed, and otherwise, a yellow solid is easily formed. The whole reaction device is sealed by adopting the aqueous solution of calcium hydroxide, and the toxic gas can be effectively absorbed by vacuumizing.

The content of each element is obtained by detecting the concentration of each ion in the solution by atomic absorption after the solution is diluted. Because the content of the solution is high and the manganese is detected by atomic absorption, the sensitivity of the manganese is high, and a large error can be caused by an overlarge dilution factor. Therefore, the test should be noted that the dilution factor cannot be more than one hundred. When preparing the standard sample, the high-concentration standard sample can be prepared by considering the analysis of the pure sample, the sensitivity is reduced by the deflection of the combustion head, and the accuracy of measurement is improved.

TABLE 2 acid leaching test results table

According to the test results, the highest yield of each element of the manganese slag is respectively as follows: 92% of manganese, 50% of aluminum and 83% of iron.

The volume of the filtrate determines the leaching rate. When the volume of the filtrate reaches about 3500mL, the leaching rate of manganese approaches to 92 percent.

2. Test for removing aluminum

Taking a certain amount of leaching solution prepared in the 3# test in the acid leaching test, firstly adding a certain amount of ammonium sulfate and then adding ammonium carbonate to adjust the pH value to be 1-3.

The volume of the stock solution in each sample is determined to be 500mL, 8.598g of aluminum, 49.391g of manganese and 2.534g of iron

TABLE 3 test Table for removing aluminum

Remarking: in Table 3, Al% represents the mass percentage of the aluminum content in the liquid after the reaction to the total amount of aluminum contained before the reaction; mn% represents the mass percentage of the manganese content in the liquid after the reaction to the total manganese content before the reaction; fe% represents the mass percentage of the iron content in the liquid after the reaction to the total amount of iron before the reaction.

And (4) putting the filtered crude ammonium alum into an oven, and drying under reduced pressure to obtain a crude ammonium alum product, wherein the purity of the alum is over 96 percent. The purity of the ammonium alum can reach more than 99.0 percent after one-time recrystallization. The product characterization is shown in fig. 1 and fig. 2.

3. Iron removal test

And (3) taking the leaching solution prepared in the test after aluminum removal to continue the iron removal test, firstly dropwise adding hydrogen peroxide until iron is completely oxidized, and then adding ammonia water to adjust the pH value to 5-6 and then filtering to obtain an iron mud filter cake and filtrate.

TABLE 4 deironing test design table

Serial number	NH₃.H₂O/ml	pH	liquid/L	pH after filtration	Dry weight of
						⑤	90.6	5.2	0.739	4.86	16
⑥	87.7	5.39	0.685	5.16	15
						⑦	169	5.7	0.739	5.33	14

TABLE 5 iron removal test results Table

	liquid/L	Fe/g	Removal rate	Al/g	Removal rate	Mn/g	Rate of loss	Iron slag
									⑤	0.739	0.009	98.96％	0.345	79.41％	48.58	18％	16
⑥	0.685	0.026	97.09％	0.208	87.54％	28.66	30％	15
									⑦	0.739	0.042	95.34％	0.235	85.96％	26.38	36％	14

The iron removal effect is good, the removal rate is maintained to be more than 95%, the removal rate of aluminum is maintained to be more than 80%, and manganese is lost. The lower the pH value in iron removal, the smaller the loss of manganese, and generally about 5.0 is preferable. Not only can reduce the loss of manganese, but also can improve the quality of iron mud.

4. Manganese precipitation test

Slowly adding excessive ammonium carbonate into leaching solution prepared after test iron removal in an iron removal test to generate carbonate ions to form manganese carbonate precipitate, standing for 1h, and filtering to obtain a manganese carbonate filter cake;

table 6 manganese precipitation test table

Serial number

(NH₄)₂CO₃/g

liquid/mL

Solids/g

Al％

Mn％

Fe％

①

25

645

30.3

8.64％

72.37％

3.31％

②

50

668

49.0

24.51％

50.14％

1.30％

③

75

590

68.4

15.63％

25.63％

0.07％

④

100

558

89.0

0.16％

7.02％

-1.08％

Remarking: in Table 6, Al% represents the mass percentage of the aluminum content in the liquid after the reaction to the total amount of aluminum contained before the reaction; mn% represents the mass percentage of the manganese content in the liquid after the reaction to the total manganese content before the reaction; fe% represents the mass percentage of the iron content in the liquid after the reaction to the total amount of iron before the reaction.

5. Preparation of active manganese dioxide from manganese precipitate

And (3) drying the manganese carbonate prepared in the previous step manganese precipitation test, and introducing oxygen to roast for 6 hours at a certain temperature. Naturally cooling the obtained black product Mn₂O₃Adding water to make pulp, adding small quantity of concentrated sulfuric acid and NaClO₃And reacted at a certain temperature for 2 hours. After the reaction is finished, filtering and washing with water until the pH of the filtrate is about 5. And drying the filter cake to obtain the black active manganese dioxide.

Suppose is provided with M₁Roasting the manganese carbonate to obtain M₂And g manganese oxide. If the oxide contains X mol MnO and Y mol MnO₂Then, there is the following formula:

X＝(87M₁-115M₂)/(115*87-115*71)

Y＝(115M₂-71M₁)/(115*87-115*71)

TABLE 7 preparation of active manganese dioxide

It can be seen that the yield of manganese in the process is maintained at about 99%, under the same conditions, the yield is not greatly affected, and the product characteristics are shown in fig. 3 and 4.

As shown in fig. 4, the content of manganese dioxide was 84.9% by EDS, which exceeds the standard of the same type of product.

6. Synthesis of 4A molecular sieve from silica slag

(1) Preparation of sodium silicate:

and washing the crude silicon slag obtained in the acid leaching test with water, roasting to obtain 350 g of silicon slag, adding 500 g of NaOH solid, uniformly stirring, slowly pouring into 4400mL of water, quickly stirring, heating to boil, and filtering to obtain a filter cake and a sodium silicate solution.

(2) Preparing a sodium aluminate solution:

700g of sodium aluminate is dissolved in 1500mL of 1mol/L sodium hydroxide solution and heated to obtain a clear sodium aluminate solution.

(3) Preparation of 4A molecular sieve:

the prepared sodium silicate solution is poured into sodium aluminate, stirred for half an hour at a high speed of 14kr/min, and then filled in a large enamel barrel and put into an oven at 100 ℃ for crystallization. Samples were taken at different times.

TABLE 84A molecular sieve test Table

	1	2	3	4	5	6	7	8	9	10
											Crystallization time/h	4	8	10	20	24	47	56	77	76	95
Crystallization temperature/. degree.C	100	100	100	100	100	100	100	100	200	220
											Mass of molecular sieve/g	57.5	44.5	88.5	146	72.5	28.0	163	23.5	38.5	73.8

The product is shown in fig. 5 and 6.

As can be seen from the analysis of FIG. 5, the crystal form is continuously complete with the time, and the 5# sample obtains a better 4A molecular sieve product after 24 hours.

7. Study on synthesis of white carbon black from silica fume

Weighing 7g of silica residue, adding the silica residue into a 500ml beaker, weighing 10g of NaOH, dissolving the NaOH in deionized water, adding the NaOH into the silica residue (about 100ml), boiling, and filtering to obtain a filtrate (mainly sodium silicate);

placing the filtrate obtained by filtering in a water bath kettle at 80 ℃, adjusting the pH value to 7-10, adding 10g of polyethylene glycol (1000), and reacting for a period of time.

And (3) dispersing the jelly obtained by the reaction in ultrasonic waves, filtering to obtain filter residues, and drying in an oven at 120 ℃.

Roasting, namely crushing the filter residue, and then roasting in a muffle furnace at 950 ℃ for 180 min.

TABLE 9 test chart for preparing white carbon black

The product characterization is shown in fig. 7 and 8. As shown in fig. 7, the particle size of the silica is significantly reduced, and the distribution range is narrowed to the most uniform sample No. 1, the particle size is concentrated around 200nm, the condition of # 6 is most economical, and the minimum particle size of around 30nm can be achieved. From FIG. 8: the infrared analysis chart of the sample No. 1 shows that: the waveform of the obtained sample is basically consistent with that of the standard white carbon black, and the characteristic wave numbers are basically overlapped.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The comprehensive utilization method of the manganese-rich slag is characterized by comprising the following steps: (1) acid leaching to prepare leaching solution and silicon slag; (2) removing aluminum from the leaching solution; (3) removing iron from the leaching solution after removing aluminum; (4) leaching solution after iron removal is used for manganese precipitation; (5) preparation of Mn by manganese carbonate oxidizing roasting₂O₃；(6)Mn₂O₃Disproportionating and oxidizing to obtain active manganese dioxide; (7) preparing white carbon black or a 4A molecular sieve by recycling the silica slag; wherein the content of the first and second substances,

(1) acid leaching to prepare leaching solution and silicon slag: adopting concentrated sulfuric acid as a leaching agent, adding excessive concentrated sulfuric acid in a dropwise manner, carrying out acid leaching reaction on manganese-rich slag containing 30-50% of Mn by mass percent, and filtering and separating to obtain leaching solution and silicon slag;

(3) removing iron from the leaching solution after aluminum removal: adding hydrogen peroxide dropwise into the leaching solution after removing aluminum until iron is completely oxidized to obtain a reddish brown solution, then adding ammonia water to adjust the pH value to 5-6, and filtering to obtain an iron mud filter cake and filtrate;

2. The comprehensive utilization method of manganese-rich slag according to claim 1, wherein in step (1), water is added into the reaction kettle, then the manganese-rich slag is added under the condition of stirring, and after the addition of the water is finished, concentrated sulfuric acid is slowly added dropwise to react for 10 hours; absorbing gas generated in the reaction process by using an aqueous solution of calcium hydroxide; 3000ml of water is added into each kilogram of manganese-rich slag, 1000ml of concentrated sulfuric acid is added into each kilogram of manganese-rich slag, the reaction temperature is controlled to be 80-95 ℃, and the mass percentage concentration of the concentrated sulfuric acid is 90-98%.

3. The comprehensive utilization method of manganese-rich slag according to claim 1, wherein in the step (2), the addition amount of ammonium sulfate, ammonium carbonate and leaching solution is 20-50g:50-60g:500 mL; a large amount of CO is generated in the reaction process₂Absorbing the gas with ammonia water to produce ammonium carbonate or ammonium bicarbonate for reuse.

4. The comprehensive utilization method of manganese-rich slag according to claim 1, wherein said preparation of 4A molecular sieve from silica slag comprises the following steps:

5. The comprehensive utilization method of manganese-rich slag according to claim 1, wherein the preparation of white carbon black from silica slag comprises the following steps: