阅读说明：本技术 一种利用镁橄榄石尾矿制取硫酸镁及白炭黑的工艺 (Process for preparing magnesium sulfate and white carbon black by using forsterite tailings ) 是由 周鑫 赵树伟 于 2019-12-07 设计创作，主要内容包括：本发明公开了一种利用镁橄榄石尾矿制取硫酸镁及白炭黑的工艺,其特征在于,包括如下步骤：三次循环制备硫酸镁、白炭黑的制备以及结晶、二氧化硅含量分析。与现有技术相比,本发明公开提供了一种利用镁橄榄石尾矿制取硫酸镁及白炭黑的工艺,其采用三次循环制备硫酸镁,通过对每一次循环中滤渣、结晶、原浆及洗液进行分析处理,来确定制备的硫酸镁的最佳含量；并且利用硫酸镁制备过程中步骤a中留存的滤渣与30％及50％的氢氧化钠溶液混合制备白炭黑,并且反复校正各种主要原料的消耗,以达到节约能源和成本的目的。(The invention discloses a process for preparing magnesium sulfate and white carbon black by utilizing forsterite tailings, which is characterized by comprising the following steps of: preparing magnesium sulfate and white carbon black by three-time circulation, and analyzing the contents of crystal and silicon dioxide. Compared with the prior art, the invention discloses a process for preparing magnesium sulfate and white carbon black by utilizing forsterite tailings, which adopts three cycles to prepare the magnesium sulfate, and determines the optimal content of the prepared magnesium sulfate by analyzing and processing filter residue, crystallization, primary pulp and washing liquor in each cycle; and mixing the filter residue remained in the step a in the magnesium sulfate preparation process with 30 percent and 50 percent of sodium hydroxide solution to prepare the white carbon black, and repeatedly correcting the consumption of various main raw materials so as to achieve the purposes of saving energy and cost.)

1. A process for preparing magnesium sulfate and white carbon black by utilizing forsterite tailings is characterized by comprising the following steps:

A. preparation of magnesium sulfate by one-time circulation

Dissolving forsterite with 50% -65% sulfuric acid:

a. under the condition of 80-100 ℃, 1000 g of 300-400 mesh forsterite is slowly added into 1000 ml of 800-1000 ml of 50-65% sulfuric acid solution, and the temperature is kept for 1-2 hours after boiling; filtering after the heat preservation time is finished, respectively metering, analyzing and storing the filtered raw pulp and washing liquor, and then washing filter residues until the pH value is 6-7 and storing for later use;

b. heating the raw stock filtrate obtained in the step a to 80-100 ℃, slowly adding 1:1 forsterite slurry, adjusting the pH of the mixed solution to 5-6, filtering, washing a filter cake with 200-300 ml of water, collecting the filtrate and washing liquid together, and analyzing the residual values of water and magnesium sulfate for later use;

c. heating the solution with the adjusted pH value in the step b to 50-60 ℃, slowly adding 50-60% lime slurry until the pH value is 7.5-8, boiling and concentrating to 30-40 Baume degrees, filtering and washing, recovering washing liquor in the stock solution, adjusting the pH value to 5, and continuously concentrating to 35-45 Baume degrees for crystallization;

d. c, controlling the crystallization speed at 300 revolutions per minute (low speed), controlling the crystallization temperature at 30-40 ℃, keeping the crystallization time at 30-40 ℃ for 12-13 hours, dehydrating after crystallization, analyzing the content of dehydrated crystals, collecting and calculating the volume of the mother liquor, analyzing the content of the mother liquor and keeping the mother liquor for later use;

B. preparation of magnesium sulfate by secondary circulation

e. B, preparing the washing liquid obtained in the step a into 50% -60% sulfuric acid solution for later use;

f. c, preparing 70% -80% slurry of the filter residue obtained after suction filtration in the step b, slowly adding the slurry into the sulfuric acid solution obtained in the step e, keeping the temperature for 1-2 hours after boiling, filtering after the heat preservation time is finished, respectively metering, analyzing and storing the filtered raw pulp and washing liquor, and washing the filter residue until the pH value is 6-7 and storing the filter residue for later use;

g. heating the raw stock filtrate obtained in the step f to 80-100 ℃, slowly adding 1:1 forsterite slurry, adjusting the pH of the solution to 5-6, filtering, washing a filter cake with 200-300 ml of water, and collecting the filtrate and the washing liquid together; collecting filter cakes, and analyzing water and magnesium sulfate residual values for later use;

h. heating the solution with the adjusted pH value in the step g to 50-60 ℃, slowly adding 50-60% lime slurry until the pH value is 7.5-8, boiling and concentrating to 30-40 Baume degrees, filtering and washing, recovering washing liquor in the stock solution, adjusting the pH value to 5, and continuously concentrating to 35-45 Baume degrees for crystallization;

i. controlling the crystallization, namely controlling the rotating speed at 300 r/min, controlling the crystallization temperature at 30-40 ℃, keeping the crystallization time at 30-40 ℃ for 12-13 hours, dehydrating and analyzing the content of dehydrated crystals after crystallization, collecting and measuring the volume of mother liquor, analyzing the content of the mother liquor and keeping the mother liquor for later use;

C. preparing magnesium sulfate in the third circulation and the second circulation;

D. preparation of white carbon black

(1) Mixing the filter residue remained in the step a in the preparation process of magnesium sulfate with 30 percent and 50 percent sodium hydroxide solution according to the ratio of alkali to residue of 4:1 respectively for standby; the reaction equation is as follows:

2NaOH+SiO₂＝Na₂SiO₃+H₂O

sufficient sodium hydroxide is prepared according to the chemical reaction formula, the molar ratio of the silicon dioxide to the sodium hydroxide is 1:2, and the water content in the slag is considered when the alkali is mixed with the slag, so that the concentration of the alkali liquor cannot be reduced;

(2) placing the mixed slurry obtained in the step 1 into a constant-temperature water bath kettle at the temperature of 80-100 ℃, stirring and reacting for 2-4 hours, and keeping stirring to operate at a low speed;

(3) filtering and washing after the reaction is finished, washing filter residues with water until the PH value is 6-7, and weighing and metering; mixing the washing liquid and the filtrate, heating to 50-60 ℃, adding 50-60% sulfuric acid until the pH value is about 3, slowly adding sodium hydroxide, increasing the stirring speed, adjusting the pH value of the mixed solution to 6.5, preserving heat, and curing for 2-4 hours;

(4) filtering and washing after heat preservation is finished, temporarily controlling the temperature of washing water at 50-60 ℃, and stopping the washing water when the conductivity of the washing water is 30 microsiesis in a soaking and suction filtration mode; the amount of washing water is metered every time of quantitative addition;

(5) drying the filter residue after washing in an oven at the temperature of 110-150 ℃, and arranging to measure the content of the silicon dioxide and measure the specific surface area of the filter residue in relation to a third party.

2. The process for preparing magnesium sulfate and white carbon black by using forsterite tailings as claimed in claim 1, wherein the reaction in the step (2) needs a distillation flask which is large in a process laboratory to isolate air.

Technical Field

The invention relates to the technical field of forsterite tailings, and particularly relates to a process for preparing magnesium sulfate and white carbon black by using forsterite tailings.

Background

Forsterite belongs to super-basic deep diagenesis, is a common diagenesis mineral, is one of the earliest formed minerals during magma crystallization, and is commonly present in pyrolites such as gabbros, basalt and olivine. The symbiotic minerals include magnetite, pyroxene, anorthite, chromite, serpentine and the like. The forsterite mainly comprises 2 MgO-SiO 2, and has a theoretical chemical composition of 57.2% of MgO and 42.8% of SiO 2. Belongs to an orthorhombic system, has higher melting point and stable crystal form, has no crystal form transformation from normal temperature to the melting point, has good high-temperature performance, and is an excellent magnesium refractory raw material. The forsterite ore resources in China are widely distributed and are mainly distributed in Yichang in Hubei, Shanxi and Xixia in Henan. However, the research on recycling of forsterite is few at present, and how to provide a process for preparing magnesium sulfate and white carbon black by using forsterite tailings can make up for the shortage of forsterite resource utilization and bring certain economic benefits is a problem to be solved urgently.

Disclosure of Invention

In view of the above, the invention provides a process for preparing magnesium sulfate and white carbon black by using forsterite tailings, and the process has the characteristics of energy conservation, low cost, simple process flow and the like.

In order to achieve the purpose, the invention provides the following technical scheme:

a process for preparing magnesium sulfate and white carbon black by utilizing forsterite tailings is characterized by comprising the following steps:

A. preparation of magnesium sulfate by one-time circulation

Dissolving forsterite with 50% -65% sulfuric acid:

a. under the condition of 80-100 ℃, 1000 g of 300-400 mesh forsterite is slowly added into 1000 ml of 800-1000 ml of 50-65% sulfuric acid solution, and the temperature is kept for 1-2 hours after boiling; filtering after the heat preservation time is finished, respectively metering, analyzing and storing the filtered raw pulp and washing liquor, and then washing filter residues until the pH value is 6-7 and storing for later use;

b. heating the raw stock filtrate obtained in the step a to 80-100 ℃, slowly adding 1:1 forsterite slurry, adjusting the pH of the mixed solution to 5-6, filtering, washing a filter cake with 200-300 ml of water, collecting the filtrate and washing liquid together, and analyzing the residual values of water and magnesium sulfate for later use;

c. heating the solution with the adjusted pH value in the step b to 50-60 ℃, slowly adding 50-60% lime slurry until the pH value is 7.5-8, boiling and concentrating to 30-40 Baume degrees, filtering and washing, recovering washing liquor in the stock solution, adjusting the pH value to 5, and continuously concentrating to 35-45 Baume degrees for crystallization;

d. c, controlling the crystallization speed at 300 revolutions per minute (low speed), controlling the crystallization temperature at 30-40 ℃, keeping the crystallization time at 30-40 ℃ for 12-13 hours, dehydrating after crystallization, analyzing the content of dehydrated crystals, collecting and calculating the volume of the mother liquor, analyzing the content of the mother liquor and keeping the mother liquor for later use;

B. preparation of magnesium sulfate by secondary circulation

e. B, preparing the washing liquid obtained in the step a into 50% -60% sulfuric acid solution for later use;

f. c, preparing 70% -80% slurry of the filter residue obtained after suction filtration in the step b, slowly adding the slurry into the sulfuric acid solution obtained in the step e, keeping the temperature for 1-2 hours after boiling, filtering after the heat preservation time is finished, respectively metering, analyzing and storing the filtered raw pulp and washing liquor, and washing the filter residue until the pH value is 6-7 and storing the filter residue for later use;

g. heating the raw stock filtrate obtained in the step f to 80-100 ℃, slowly adding 1:1 forsterite slurry, adjusting the pH of the solution to 5-6, filtering, washing a filter cake with 200-300 ml of water, and collecting the filtrate and the washing liquid together; collecting filter cakes, and analyzing water and magnesium sulfate residual values for later use;

h. heating the solution with the adjusted pH value in the step g to 50-60 ℃, slowly adding 50-60% lime slurry until the pH value is 7.5-8, boiling and concentrating to 30-40 Baume degrees, filtering and washing, recovering washing liquor in the stock solution, adjusting the pH value to 5, and continuously concentrating to 35-45 Baume degrees for crystallization;

i. controlling the crystallization, namely controlling the rotating speed at 300 r/min, controlling the crystallization temperature at 30-40 ℃, keeping the crystallization time at 30-40 ℃ for 12-13 hours, dehydrating and analyzing the content of dehydrated crystals after crystallization, collecting and measuring the volume of mother liquor, analyzing the content of the mother liquor and keeping the mother liquor for later use;

C. preparing magnesium sulfate in the third circulation and the second circulation;

D. preparation of white carbon black

(1) Mixing the filter residue remained in the step a in the preparation process of magnesium sulfate with 30 percent and 50 percent sodium hydroxide solution according to the ratio of alkali to residue of 4:1 respectively for standby; the reaction equation is as follows:

2NaOH+SiO₂＝Na₂SiO₃+H₂O

sufficient sodium hydroxide is prepared according to the chemical reaction formula, the molar ratio of the silicon dioxide to the sodium hydroxide is 1:2, and the water content in the slag is considered when the alkali is mixed with the slag, so that the concentration of the alkali liquor cannot be reduced;

(2) placing the mixed slurry obtained in the step 1 into a constant-temperature water bath kettle at the temperature of 80-100 ℃, stirring and reacting for 2-4 hours, and keeping stirring to operate at a low speed;

(3) filtering and washing after the reaction is finished, washing filter residues with water until the PH value is 6-7, and weighing and metering; mixing the washing liquid and the filtrate, heating to 50-60 ℃, adding 50-60% sulfuric acid until the pH value is about 3, slowly adding sodium hydroxide, increasing the stirring speed, adjusting the pH value of the mixed solution to 6.5, preserving heat, and curing for 2-4 hours;

(4) filtering and washing after heat preservation is finished, temporarily controlling the temperature of washing water at 50-60 ℃, and stopping the washing water when the conductivity of the washing water is 30 microsiesis in a soaking and suction filtration mode; the amount of washing water is metered every time of quantitative addition;

(5) drying the filter residue after washing in an oven at the temperature of 110-150 ℃, and arranging to measure the content of the silicon dioxide and measure the specific surface area of the filter residue in relation to a third party.

Preferably, in the above process for preparing magnesium sulfate and white carbon black by using forsterite tailings, the reaction in the step (2) needs to be isolated from air by using a distillation flask which is large in a process laboratory.

According to the technical scheme, compared with the prior art, the invention discloses a process for preparing magnesium sulfate and white carbon black by utilizing forsterite tailings, wherein the magnesium sulfate is prepared by three times of circulation, and the optimal content of the prepared magnesium sulfate is determined by analyzing and processing filter residue, crystallization, primary pulp and washing liquor in each circulation; mixing the filter residue remained in the step a in the preparation process of magnesium sulfate with 30% and 50% of sodium hydroxide solution to prepare white carbon black, and repeatedly correcting the consumption of various main raw materials, so that on one hand, a cyclic development mode of resource product waste renewable resource products can be realized, and the purposes of maximum resource reduction, highest utilization efficiency and optimal economic benefit are achieved; on the other hand, the latest optimal process technology is selected in all production links in the factory, so that the ecological environment safety in the area is ensured, and the unification of environmental benefits, social benefits and enterprise economic benefits is realized.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention discloses a process for preparing magnesium sulfate and white carbon black by utilizing forsterite tailings, which has the characteristics of energy conservation, low cost, simple process flow and the like.

The working principle of the invention is as follows:

under certain conditions, forsterite reacts with sulfuric acid as follows:

Mg₂SiO₄+H₂SO₄→2MgSO₄+H₂SiO₃+H₂O (2.9)

FeO+H₂SO₄→FeSO₄+H₂O (2.10)

the following reaction occurs in the course of removing impurities with ferrous sulfate:

FeSO₄+Ca(OH)₂→Fe(OH)₂↓+CaSO₄(2.11)

and (3) carrying out spray crystallization on the magnesium sulfate solution to generate magnesium sulfate monohydrate:

MgSO₄+H₂O→MgSO₄·H₂O (2.12)

in the alkali dissolution process, silicic acid reacts with sodium hydroxide to generate sodium silicate, and the sodium silicate is neutralized by sulfuric acid to generate precipitated white carbon black:

H₂SiO₃+2NaOH→Na₂SiO₃+2H₂O (2.13)

Na₂SiO₃+H₂SO₄→2Na₂SO₄+SiO₂·H₂O↓ (2.14)。

the experimental results of the present invention are compared as follows:

1. comparison of magnesium sulfate test results

2. Comparison of Experimental results of white carbon Black

Item	At a time	Two times
			Once filter residue (g)	500 (moisture 71.26%)	500 (moisture 71.26%)
SiO2 content (%)	56.18	56.18
			NaOH(g)	300	162
50% sulfuric acid solution (ml)	320	150
			Waste residue (g)	84.54	101
White carbon black (g) product	68.9	153

3. List of results of iron removal and filtration:

analysis item	One cycle	Secondary circulation	Three times of circulation
				Quality (g)	764	2630	6155
Moisture (%)	54.76	58.5	61.56
				Fe2O3 content (%)	14.49	9.99	5.31
CaO content (%)	15.77	16.24	17.11
				MgO content (%)	14.02	14.86	15.61
Al2O content (%)	0.96	0.41	0.41

4. Analysis of mother liquor results

Magnesium sulfate main material and waste residue output condition table

Silica main material and waste residue condition table

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.