Waste tire pyrolysis carbon black upgrading and purifying method

Abstract

The invention provides an upgrading and purifying method for waste tire pyrolysis carbon black, and belongs to the technical field of upgrading, purifying and high-value utilization of waste tires and waste rubber pyrolysis carbon black. The upgrading and purifying method comprises the following steps: carrying out wet magnetic separation on waste tire pyrolysis carbon black to obtain pyrolysis carbon black subjected to magnetic separation; mixing the cracked carbon black subjected to magnetic separation with hydrobromic acid for acid leaching to obtain first acid leaching filtrate and a first carbon black product; adding zinc particles into the first acid leaching filtrate to obtain second filtrate; evaporating and crystallizing the zinc bromide solution to obtain zinc bromide; zinc bromide is prepared into heavy liquid, the first carbon black product is subjected to reselection, and a pure carbon black product and silicon dioxide tailings are obtained; introducing hydrogen sulfide gas into the ferric ion solution for purification and absorption to obtain sulfur and a third filtrate; and the third filtrate is subjected to electrolytic regeneration, and a regenerated ferric ion solution and hydrogen are obtained after electrolytic regeneration is finished. According to the method, the acid leaching byproduct zinc bromide is used as a reselection medium, and resource recycling is achieved while efficient separation and impurity removal are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste tire, waste rubber pyrolysis carbon black upgrading, purification and high-value utilization, and more particularly to a method for upgrading and purifying waste tire pyrolysis carbon black. Background Art

[0002] With the rapid development of the automotive industry, the generation of waste tires has been increasing year by year. The increasing production of waste tires has brought huge pressure to the environment. Therefore, the recycling and treatment of waste tires have become a hot environmental issue. Exploring and developing waste tire recycling technologies aims to convert them into valuable products through means such as green chemistry and circular economy, so as to reduce environmental pressure and promote sustainable development.

[0003] Waste tires are rich in various valuable secondary resources. At present, the treatment methods of waste tires mainly include: direct utilization - tire retreading, recycling - recycled rubber powder, thermochemical utilization - incineration for power generation and pyrolysis. Direct utilization cannot achieve full-category recycling and may have potential safety hazards; the recycled rubber or recycled rubber powder produced by recycling needs to be desulfurized and is prone to secondary pollution; although incineration for power generation can provide fuel for power plants, it will cause serious air pollution and resource waste; the pyrolysis method can effectively separate the main components of waste tires, and the pyrolysis oil, pyrolysis carbon black and pyrolysis gas are all flammable, so the pyrolysis products can be used as energy commodities, which indicates that pyrolysis has broad application prospects in the recycling of waste tires.

[0004] The solid product obtained after the pyrolysis of waste tires is pyrolysis carbon black. However, due to the relatively high content of ash impurities in waste tire pyrolysis carbon black, the ash content is generally about 20%. In the ash of pyrolysis carbon black, silica, zinc sulfide, and calcium carbonate account for more than 90% of the ash impurities. The existence of these ash impurities will affect its commercial properties and market demand. Therefore, it is of great significance to purify waste tire pyrolysis carbon black to improve its purity and performance.

[0005] At present, the purification methods of pyrolytic carbon black mainly include physical methods and chemical methods. Among them, physical methods mainly use screening, magnetic separation and direct flotation for purification. Magnetic separation is mainly aimed at magnetic substances and is basically ineffective for non-magnetic mixtures; screening is mainly used to separate materials with different particle sizes, but for ultra-fine particles of pyrolytic carbon black below 200 mesh, the existing screening technologies are difficult to meet the requirements; direct flotation has always been regarded as the most potential purification method for pyrolytic carbon black by researchers. However, it has been found in practice that the ash reduction effect of conventional bubble flotation is not significant, generally about 2%-5%. For pyrolytic carbon black containing about 20% ash impurities, the ash reduction effect still cannot meet the commercial standard. This is mainly because the particles of pyrolytic carbon black are relatively fine and the surface properties are complex, and it is difficult to dissociate carbon black particles and impurities by traditional mechanical grinding.

[0006] Patent CN202310027740.3 proposes a combined beneficiation and metallurgy purification method for pyrolytic carbon black. After pyrolytic carbon black is leached with ammonium persulfate to remove calcium salts and zinc salts, nano-bubbles are used for flotation. However, at present, the nano-bubble flotation beneficiation technology is still in the laboratory development stage, and has not reached the maturity and industrialization level of the conventional bubble flotation separation technology. A certain amount of technical accumulation is still needed to realize its industrial application; moreover, the surface of pyrolytic carbon black is rich in active groups such as hydroxyl, carbonyl, carboxyl, and lactone groups. These functional groups make pyrolytic carbon black prone to react with oxygen in the air. The large specific surface area and porous structure of pyrolytic carbon black will further increase the risk of its oxidation. When pyrolytic carbon black is oxidized, it is difficult to separate carbon particles from quartz particles even by using nano-bubble flotation, which will lead to poor nano-bubble flotation effect, difficult separation of quartz particles and carbon particles, and increased ash content of the floated matter.

[0007] Chemical methods mainly use acid / alkali washing and oxidative leaching to desalt pyrolytic carbon black. Traditional purification processes mainly use hydrofluoric acid or inorganic strong acids such as hydrochloric acid, sulfuric acid, and nitric acid to remove impurities from pyrolytic carbon black. Due to problems such as slow reaction rate and poor ash reduction effect of weak acids such as acetic acid and formic acid, the current chemical purification method mainly focuses on strong acid leaching.

[0008] Gravity separation is also a common physical separation method, mainly achieving separation based on the density differences among different components in the separated materials. According to the types of heavy media used, heavy liquid separation can be divided into organic heavy liquid separation and inorganic heavy liquid separation. So far, the application of gravity separation in the purification of pyrolytic carbon black is less, but the gravity separation method has been maturely applied in the fields of coal preparation and mineral processing for nearly a century. Heavy liquid separation has the advantages of large processing capacity, short process flow, recyclable heavy media, high precision, wide separation density, significant economic benefits, and no change in the chemical structure of the selected materials, so it is still widely used in coal preparation plants and mineral processing plants. Due to the significant density differences among carbon particles, silica, and zinc salts in pyrolytic carbon black, the gravity separation method has great potential and industrialization prospects in the separation and purification of pyrolytic carbon black.

[0009] Organic heavy liquid separation generally uses organic heavy liquids mixed with benzene, chloroform, bromoform, etc. to separate pyrolytic carbon black. Moreover, the organic solvents themselves have certain dispersibility and solubility, making them excellent heavy separation media for pyrolytic carbon black. However, organic heavy liquids are prone to volatilization at room temperature, which can cause corrosion to equipment, pollution to the air, and harm to the health of operating workers. Organic heavy liquids usually produce toxic gases when heated. In addition, it is difficult to separate organic heavy liquids from the separation products, resulting in difficult recovery, which increases the complexity and cost of subsequent treatment.

[0010] Regarding the characteristics that silica in pyrolytic carbon black does not react with common acids (except hydrofluoric acid), and there is a significant density difference between silica and carbon particles, and the embedded particle size of impurities in pyrolytic carbon black is relatively fine, usually below 45μm, which causes the loss of selectivity of conventional gravity separation methods such as jigging, shaking tables, and cyclones, resulting in poor ash removal effect. Therefore, it is of great significance to develop an efficient gravity separation method for pyrolytic carbon black. Summary of the Invention

[0011] In view of the above problems, the present invention provides a method for upgrading and purifying waste tire pyrolytic carbon black, which uses hydrobromic acid leaching for desalination, evaporation and concentration to prepare zinc bromide heavy liquid, gravity separation for silicon removal, hydrogen sulfide waste gas purification, electrolysis of the third filtrate to produce hydrogen and regeneration of ferric ions, etc. to effectively recover various valuable components in pyrolytic carbon black. The method still belongs to the combined beneficiation and metallurgy method, with simple and efficient process, and can achieve full-component recovery without causing secondary pollution to the environment.

[0012] The present invention provides a method for upgrading and purifying waste tire pyrolytic carbon black, including the following steps: Perform wet magnetic separation on waste tire pyrolytic carbon black to remove iron filings, and obtain pyrolytic carbon black after magnetic separation.

[0013] Mix the cracked carbon black after magnetic separation with hydrobromic acid for acid leaching. During the acid leaching process, metal salts are removed to obtain hydrogen sulfide gas, the first acid leaching filtrate, and the first carbon black product.

[0014] Add zinc particles to the first acid leaching filtrate, and a displacement reaction occurs to obtain hydrogen gas, unreacted zinc particles, and the second filtrate.

[0015] Evaporate and crystallize the second filtrate to obtain zinc bromide.

[0016] Add a solvent to zinc bromide to prepare a heavy liquid, and perform heavy separation on the first carbon black product to obtain a pure carbon black product and silica tailings.

[0017] Pass the hydrogen sulfide gas into a ferric ion solution for purification and absorption. During the purification and absorption process, hydrogen sulfide is oxidized to sulfur and hydrogen ions are generated, and ferric ions are reduced to ferrous ions. After the purification and absorption is completed, filter to obtain sulfur and the third filtrate.

[0018] Electrolytically regenerate the third filtrate. During the electrolytic regeneration process, ferrous ions are oxidized to ferric ions at the anode, and hydrogen ions are reduced to hydrogen gas at the cathode. After the electrolytic regeneration is completed, a regenerated ferric ion solution and hydrogen gas are obtained, and the regenerated ferric ions are recycled in the purification and absorption step.

[0019] In one embodiment of the present invention, in the acid leaching step, the concentration of hydrobromic acid is 0.2 mol / L to 5 mol / L, the pulp concentration is 50 g / L to 200 g / L, the leaching temperature is 30 °C to 90 °C, the leaching time is 30 min to 150 min, and the acid leaching ultrasonic frequency is 30 kHz to 80 kHz.

[0020] In one embodiment of the present invention, during heavy separation, the mass ratio of the heavy liquid to the first carbon black product is 2 to 30:1, the ultrasonic frequency is 20 - 50 kHz, and the ultrasonic time is 5 min to 25 min. When using the heavy liquid as the separation medium, the heavy separation equipment is one or more of a centrifuge, a jig, a centrifugal concentrator, a hydrocyclone, a shaking table, a spiral chute, a fan chute, a vibrating chute, an inclined chute separator, a Mozley multi-product heavy separator, a Falcon centrifugal separator, a Knelson gravity separator, a Kelsey centrifugal jig, an Altair centrifugal jig, a Teeer-bed separator, a hydraulic classifier, a mud classifier, and a sedimentation tank. The particle dispersion system during heavy separation is ultrasonic dispersion, the ultrasonic frequency is 20 kHz to 50 kHz, and the ultrasonic time is 5 min to 25 min.

[0021] In one embodiment of the present invention, the centrifugal speed for heavy separation is 600 r / min to 3000 r / min, and the centrifugal time is 3 min to 25 min.

[0022] In one embodiment of the present invention, the density of the heavy liquid is 1.2 g / cm 3 ~3.2 g / cm 3 , and the solvent is one or more of water, organic solvents, alkaline cleaning agents, acidic cleaning agents, bio-enzyme cleaning agents, surfactants, and degreasing agent solutions.

[0023] In one embodiment of the present invention, during wet magnetic separation, water is added to the waste tire pyrolytic carbon black to obtain a pulp; the pulp concentration is 50 g / L to 200 g / L, the magnetic flux of the magnetic roller is 2000 Gs to 8000 Gs, and the rotational speed of the magnetic roller is 80 r / min to 150 r / min.

[0024] In one embodiment of the present invention, during the displacement reaction, the stirring speed is 300 r / min to 2000 r / min, the reaction time is 15 min to 150 min; the pH is 2.5 to 6.5, the particle size of the metallic zinc particles is 0.2 mm to 3 mm; the solid-liquid ratio of the zinc particles to the filtrate A is 30 g / L to 140 g / L.

[0025] In one embodiment of the present invention, the evaporation and crystallization steps are as follows: the evaporation temperature is 120 °C to 250 °C, and then it is evaporated to 50 °Be to 100 °Be, and cooled and crystallized at 10 °C to 40 °C.

[0026] In one embodiment of the present invention, in the purification and absorption step, the reaction temperature is 25 °C to 80 °C, the concentration of ferric ions is 0.1 mol / L to 2.5 mol / L, the hydrogen ion concentration in the ferric ion solution is 0.5 mol / L to 6 mol / L, and the liquid level height of the ferric ion solution is 30 cm to 150 cm. Further, the ferric ion solution is one or more of ferric chloride, ferric sulfate, ferric nitrate, ferric bromide, ferric phosphate, ferric citrate, ferric oxalate, ferric periodate, ferric succinate, ferric acetate, ferric perchlorate, ferric carbonate, a mixed solution of ferric hydroxide and an acid (such as acetic acid, hydrochloric acid, hydrobromic acid, etc.), a mixed solution of iron oxide and a strong acid (such as hydrochloric acid, nitric acid, sulfuric acid, etc.), a mixed solution prepared by adding hydrogen peroxide to iron filings and a strong acid, a mixture of ferric ions and an acid, a mixture of a ferric ion-containing iron source, an acid, and an oxidizing agent (where the acid can be one or several of inorganic or organic acids such as acetic acid, hydrochloric acid, concentrated sulfuric acid, aqua regia, etc., and the oxidizing agent can be one or several of inorganic or organic oxidizing agents such as potassium permanganate, oxygen, chlorine, bromine, peracetic acid, etc.), and a mixed solution prepared by mixing a ferric ion solution and an oxidizing agent (where the oxidizing agent can be one or several of potassium permanganate, nitric acid, ozone, oxygen, hydrogen peroxide, bromine, chlorine, iodine, fluorine, sodium peroxide, persulfate, potassium dichromate, manganese dioxide, nitrate, lead tetroxide, chromium trioxide, concentrated sulfuric acid, organic peroxides, aqua regia, chlorates, hypochlorites, chlorine dioxide, peracetic acid, potassium iodate, etc.).

[0027] When performing purification and absorption, the reaction vessel for hydrogen sulfide gas and ferric ions is one or more of an absorption tower, a spray tower, a scrubbing tower, a jet gas-liquid mixer, a Venturi tube, a mechanical stirring gas-liquid mixer, a bubble column (bubble column), a microporous membrane gas-liquid mixer, a gas-liquid spray mixer, a cyclone gas-liquid mixer, a static mixer, a pressurized vessel type gas-liquid mixing method, a countercurrent gas-liquid mixing method, a gas-liquid circulation mixer, a dissolved gas mixer, a gas-liquid pipeline mixer, a sonic gas-liquid mixer, a gas-liquid spiral mixer, a vortex air flow mixer, and a plate hole type gas-liquid mixer.

[0028] In one embodiment of the present invention, during the electrolytic regeneration process, the electrolytic temperature is 40°C to 80°C, the electrolytic voltage is 0.5V to 3V, the ferrous ion concentration is 0.1mol / L to 1.5mol / L, and the hydrogen ion concentration is 0.5mol / L to 3mol / L. Further, the regenerated ferric iron solution obtained during the electrolytic regeneration process is transported to the purification and absorption step for recycling. When transporting, one or several of a pump, a pipeline system, a screw conveyor, a siphon, an ejector, and a U-shaped pipeline system can be used.

[0029] Compared with the prior art, the present invention has the following beneficial effects: (1) Starting from the mineralogical composition of waste tire pyrolytic carbon black, aiming at the characteristic that hydrobromic acid does not chemically react with silicon dioxide in pyrolytic carbon black, and there is a density difference between silicon dioxide and carbon particles, and zinc bromide is a commonly used inorganic heavy liquid separation medium, a series of steps such as acid leaching of pyrolytic carbon black with hydrobromic acid, recovery of acid leaching by-products as valuable resources, and purification and conversion of waste gas into valuable resources will make full use of the physical and chemical properties of pyrolytic carbon black raw materials and by-products, improve the quality and purification of pyrolytic carbon, and realize resource recovery, without causing secondary pollution to the environment, and can recover all components of waste tire pyrolytic carbon black. Acid leaching treatment of pyrolytic carbon black with hydrobromic acid and using the by-product zinc bromide to prepare an inorganic heavy liquid, and then performing gravity separation on the acid-leached pyrolytic carbon black, realizing a fully enclosed internal circulation of the process flow, significantly reducing the cost of heavy liquid separation, and achieving the production goal of zero discharge and closed-loop of the entire process flow.

[0030] (2) Using the acid leaching by-product to prepare a zinc bromide heavy liquid with an appropriate density to perform gravity separation on silicon dioxide and carbon particles in the acid-leached pyrolytic carbon black provides a new way for the purification of pyrolytic carbon black. In this way, the by-product zinc bromide can be converted into a valuable heavy medium, reducing the use of chemical products such as inorganic salt heavy liquids, improving the resource utilization rate, and reducing the environmental pollution risk, achieving the dual goals of economic benefits and environmental protection.

[0031] (3) Using a ferric ion solution with a relatively low cost as the absorbent to recover hydrogen sulfide, a by-product generated during the hydrobromic acid leaching of pyrolytic carbon black. This not only purifies the toxic hydrogen sulfide gas under sealed conditions but also produces sulfur products and hydrogen ions. This avoids the emission of harmful substances, achieves the harmless treatment of toxic gases, and produces sulfur, a strategic material, thus realizing a win-win situation for strategic resource security and environmental protection.

[0032] (4) The electrolysis method realizes the regeneration of the ferric ion absorbent. The purification absorbent for hydrogen sulfide gas mainly contains ferrous ions, ferric ions, and hydrogen ions. By electrolyzing the absorbent after purification, ferrous ions will be electrolyzed into ferric ions at the anode to achieve the regeneration of ferric ions, while the waste acid solution formed by hydrogen ions will be electrolyzed into hydrogen at the cathode. Hydrogen can be used as a new energy fuel, and the regenerated ferric ions will be recycled and reused as the absorbent for hydrogen sulfide gas.

[0033] (5) The method of the present invention can not only efficiently separate the original pyrolytic carbon black material, and even the pyrolytic carbon black after oxidation can still maintain high efficiency and high-precision separation, but also has mature technology, a simple process, and broad prospects for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is the process flow chart of the present invention.

[0035] Figure 2 is the influence of acid concentration on the ash content of pyrolytic carbon black during the hydrobromic acid leaching process.

[0036] Figure 3 is the XRD comparison chart of pyrolytic carbon black before and after leaching.

[0037] Figure 4 is the XRD chart of pyrolytic carbon black after gravity separation after acid leaching. DETAILED DESCRIPTION OF THE INVENTION

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] When purifying and upgrading the pyrolysis carbon black from waste tires, first, the raw pyrolysis carbon black is fully wetted and stirred to be dispersed, and then magnetic separation is carried out to remove the iron filings remaining in the carbon black. Then, the raw pyrolysis carbon black after magnetic separation is acid-leached with hydrobromic acid to obtain hydrogen sulfide gas, the first acid-leaching filtrate and the first carbon black product. The mechanism of demineralization of this pyrolysis carbon black is as follows: hydrobromic acid undergoes a metathesis reaction with zinc sulfide in the pyrolysis carbon black to generate zinc bromide and hydrogen sulfide gas (ZnS + 2HBr → Zn 2+ + 2Br - + H2S↑). Zinc sulfide is an insoluble salt, and after being leached with hydrobromic acid, it will become highly soluble zinc bromide and remain in the first acid-leaching filtrate. Moreover, zinc bromide is a commonly used inorganic heavy medium. If the by-product zinc bromide after purifying the pyrolysis carbon black is used as a heavy medium for heavy separation of the first carbon black product after acid-leaching with hydrobromic acid, the recycling and reuse of the by-product zinc bromide will greatly improve the research value of the purification of pyrolysis carbon black by acid-leaching with hydrobromic acid.

[0040] The obtained hydrogen sulfide gas is inhaled into the ferric ion mixed solution through a Venturi tube type gas-liquid mixer. The ferric ion reacts with the hydrogen sulfide gas to generate sulfur and ferrous ions (2Fe 3+ + H2S → S↓ + 2Fe 2+ + 2H + ). After separating sulfur by filtration, the obtained third filtrate is electrolytically regenerated, and the ferrous ions will be reduced to ferric ions (2Fe 2+ + 2H + → 2Fe 3+ + H2↑).

[0041] Excessive zinc particles are added to the obtained first acid-leaching filtrate containing zinc bromide. The zinc particles react with the remaining hydrobromic acid in the first acid-leaching filtrate to generate zinc bromide and hydrogen gas (Zn + 2HBr → Zn 2+ + 2Br - + H2↑), and a relatively pure second filtrate of zinc bromide is obtained. The second filtrate containing zinc bromide is evaporated and concentrated to remove water to obtain solid anhydrous zinc bromide. The obtained by-product zinc bromide solid is prepared into a zinc bromide heavy liquid for heavy separation of the pure carbon black product after acid-leaching with hydrobromic acid.

[0042] Zinc bromide is highly soluble in water, with a solubility of up to 447 g / 100 mL in water at room temperature. Compared with organic heavy liquids, zinc bromide is not easily decomposed or volatilized to produce toxic and harmful gases at high temperatures; the preparation process of zinc bromide heavy liquid is relatively simple, and it can be recycled and purified for repeated use, with relatively low comprehensive cost, making it an efficient and reliable high-density medium choice in mineral separation. After mixing carbon black products with zinc bromide heavy liquid, based on the significant density difference between carbon particles and silica particles in pyrolytic carbon black, using zinc bromide heavy liquid with a density between carbon particles and silica particles, the two can be quickly separated under the strengthening effect of centrifugal force to obtain relatively pure carbon particle floats and silica sediments.

[0043] The method according to the present invention can not only achieve efficient separation of carbon black and impurities, but also reduce production costs, and at the same time promote the recycling of resources.

[0044] The raw ore of pyrolytic carbon black mainly consists of zinc salt (ZnS), calcium salt (CaCO3), silica (SiO2) and carbon (C).

[0045] Example 1 (1) After mixing the raw ore of pyrolytic carbon black with water and stirring to disperse it to form a pulp, magnetic separation is carried out using a wet magnetic separator; the pulp concentration is 150 g / L, the magnetic flux of the magnetic roller is 3000 Gs, the rotation speed of the magnetic roller is 100 r / min, iron filings and carbon black pulp products are obtained, and during this process, the removal rate of iron filings is higher than 95%.

[0046] (2) Under ultrasonic conditions, hydrobromic acid is added to the carbon black pulp product after magnetic separation to perform desalting treatment on waste tire pyrolytic carbon black. After leaching, hydrogen sulfide gas and zinc bromide solution will be generated in the pyrolytic carbon black (ZnS + 2HBr → Zn 2+ + 2Br - + H2S↑). During the acid leaching process, the ultrasonic frequency is 50 kHZ, the leaching temperature is 60 °C, the leaching time is 90 min, the solid-liquid ratio of pyrolytic carbon black and hydrobromic acid solution is 75 g / L, the concentration of hydrobromic acid in the hydrobromic acid solution is 2 mol / L. After removing metal salts, the first acid leaching filtrate and the first carbon black product are obtained by filtration. The solid first carbon black product enters the next process, and the removal rate of zinc sulfide in this step is higher than 98%.

[0047] (3) Metal zinc particles are added to the first acid leaching filtrate to undergo a displacement reaction with hydrogen ions in the filtrate to generate hydrogen and zinc bromide (Zn + 2HBr → Zn 2+ + 2Br -(+H2↑), the stirring speed is 800 r / min, and the reaction time is 45 min; the pH at the end of the reaction is controlled at about 5.0, and the particle size of the metallic zinc particles is 0.5 mm to 2 mm; the concentration of the metallic zinc particles in the first acid leaching filtrate is 60 g / L. After the reaction is completed, the unreacted metallic zinc particles and the second filtrate are obtained by filtration.

[0048] (4) Heat and evaporate the filtered second filtrate and crystallize it. The evaporation temperature is controlled at 180 °C, then it is evaporated to 80 °Be, and cooled and crystallized at 20 °C. Centrifugation is used for dehydration, and a drying device is used to dry the solid product of the centrifuge to obtain zinc bromide crystals.

[0049] (5) Configure the zinc bromide crystals obtained in step (4) into a zinc bromide heavy liquid. The solvent used for the zinc bromide heavy liquid is a mixed solution of pure water and absolute ethanol. In the mixed solution of pure water and absolute ethanol, the volume percentage of water is 85%, and the volume percentage of absolute ethanol is 15%. Use the mixed solution of pure water and absolute ethanol to dissolve the zinc bromide crystals, and the density of the heavy liquid is 1.7 g / cm 3 , add the first carbon black product to the zinc bromide heavy liquid, the liquid-solid mass ratio is 10:1, ultrasonic for 15 min to promote its dispersion, the ultrasonic frequency is 30 kHz, then use a centrifuge to accelerate the separation and stratification of carbon particles and silica particles, the centrifugation speed is 2000 r / min, and the centrifugation time is 10 min. Pour out the separated pyrolytic carbon black layer by layer, and the floating matter - pure carbon black product and the sediment - silica tailings can be obtained.

[0050] (6) Inhale the hydrogen sulfide gas obtained during the acid leaching process in step (2) into the ferric ion solution prepared with ferric chloride through a jet mixer. The flow rate at the throat of the jet pipe is 40 m / s, keep the temperature of the ferric ion solution at 70 °C, the concentration of ferric ions is 1.5 mol / L, add hydrochloric acid to keep the hydrogen ion concentration at about 1 mol / L to prevent the hydrolysis of ferric ions, the liquid level height of the ferric ion solution is 50 cm, and the gas overflowing from the liquid level of the purification pool is also inhaled into the jet mixer for secondary absorption. Under these conditions, the hydrogen sulfide gas is oxidized into sulfur and hydrogen ions are produced, and the ferric ions are reduced to ferrous ions (H2S + Fe 3+ → 2H + + S↓ + Fe 2+ ) remains in the solution, and sulfur and the third filtrate are obtained by filtration. During this process, the absorption rate of hydrogen sulfide is higher than 99%.

[0051] (7) Pump the third filtrate into the electrolytic cell for electrolytic regeneration. Add a small amount of hydrochloric acid to adjust the solution to acidic, inhibit the hydrolysis of ferric ions, and regulate the conductivity of the solution. Use graphite as the anode and platinum-coated titanium mesh as the cathode. The plate spacing is 15 cm, the electrolytic cell voltage is 2 V, and a DC power supply is used. Ferrous ions are oxidized to ferric ions at the anode (2Fe 2+ →2Fe 3 + +2e - ) and remain in the solution. Hydrogen ions are reduced to hydrogen gas at the cathode (2H + +2e - →H2↑). The hydrogen gas floats to the surface and is collected in the sealed space above the liquid level of the electrolytic cell. The electrolysis temperature is 60 °C, the concentration of ferrous ions is 0.5 mol / L, the hydrogen ion concentration is controlled at about 2.5 mol / L, and an online ultraviolet-visible spectrometer is used to detect the Fe³⁺ concentration to ensure that the regeneration efficiency is greater than 95%.

[0052] (8) Use a pump to transport the ferric ion solution obtained from the electrolytic regeneration in step 7 back to step (6) for recycling as the absorption liquid for purifying hydrogen sulfide waste gas.

[0053] With the above parameters selected for the acid leaching process of the present invention, the yield of cracked carbon black after leaching is higher than 89%, and the ash content is lower than 11%; with the above parameters selected for the gravity separation process, the yield of cracked carbon black is higher than 92%, and the ash content is lower than 3%.

[0054] Example 2 (1) Mix the raw ore of cracked carbon black with water and stir to disperse it to form a pulp, and use a wet magnetic separator for magnetic separation; the pulp concentration is 150 g / L, the magnetic flux of the magnetic roller is 3000 Gs, the rotation speed of the magnetic roller is 100 r / min, and iron filings and a carbon black pulp product are obtained. During this process, the removal rate of iron filings is higher than 95%.

[0055] (2) Under ultrasonic conditions, add hydrobromic acid to the carbon black pulp product after magnetic separation to desalt the waste tire cracked carbon black. After leaching, hydrogen sulfide gas and zinc bromide solution will be generated from the cracked carbon black (ZnS + 2HBr → Zn 2+ +2Br - +H2S↑). During the acid leaching process, the ultrasonic frequency is 50 kHZ, the leaching temperature is 60 °C, the leaching time is 90 min, the solid-liquid ratio of the cracked carbon black to the hydrobromic acid solution is 75 g / L, the concentration of hydrobromic acid in the hydrobromic acid solution is 0.5 mol / L. After removing metal salts, the first acid leaching filtrate and the first carbon black product are obtained by filtration. The solid first carbon black product enters the next process. The removal rate of zinc sulfide in this step is about 75%.

[0056] (3) Add metallic zinc particles to the first acid leaching filtrate. A displacement reaction occurs between the zinc particles and the hydrogen ions in the filtrate to produce hydrogen gas and zinc bromide (Zn + 2HBr → Zn 2+ + 2Br - + H2↑). The stirring speed is 800 r / min, and the reaction time is 45 min. The pH at the end of the reaction is controlled at around 5.0. The particle size of the metallic zinc particles is 0.5 mm - 2 mm. The concentration of the metallic zinc particles in the first acid leaching filtrate is 60 g / L. After the reaction is completed, filter to obtain the unreacted metallic zinc particles and the second filtrate.

[0057] (4) Heat and evaporate and crystallize the filtered second filtrate. The evaporation temperature is controlled at 180°C, and then evaporate until it reaches 80°Be. Cool and crystallize at 20°C. Use a centrifuge for dehydration, and use a drying device to dry the solid product of the centrifuge to obtain zinc bromide crystals.

[0058] (5) Prepare the zinc bromide heavy liquid with the zinc bromide crystals obtained in step (4). The solvent used for the zinc bromide heavy liquid is a mixed solution of pure water and absolute ethanol. In the mixed solution of pure water and absolute ethanol, the volume percentage of water is 85%, and the volume percentage of absolute ethanol is 15%. Use the mixed solution of pure water and absolute ethanol to dissolve the zinc bromide crystals. The density of the heavy liquid is 1.7 g / cm 3 , add the first carbon black product to the zinc bromide heavy liquid. The liquid-solid mass ratio is 10:1. Ultrasonic for 15 min to promote its dispersion. The ultrasonic frequency is 30 kHz. Then use a centrifuge to accelerate the separation and stratification of the carbon particles and silica particles. The centrifugal speed is 2000 r / min, and the centrifugal time is 10 min. Pour out the separated pyrolytic carbon black layer by layer, and the floating matter - pure carbon black product and the sediment - silica tailings can be obtained.

[0059] (6) Inhale the hydrogen sulfide gas obtained during the acid leaching process in step (2) into the ferric ion solution prepared with ferric chloride through a jet mixer. The flow velocity at the throat of the jet pipe is 40 m / s. Keep the temperature of the ferric ion solution at 70°C. The concentration of ferric ions in the ferric ion solution is 1.5 mol / L. Add hydrochloric acid to keep the hydrogen ion concentration at around 1 mol / L to prevent the hydrolysis of ferric ions. The liquid level height of the ferric ion solution is 50 cm. The gas overflowing from the purification pool liquid surface is also inhaled into the jet mixer for secondary absorption. Under these conditions, oxidize the hydrogen sulfide gas into sulfur and produce hydrogen ions, and the ferric ions are reduced to ferrous ions (H2S + Fe 3+ → 2H + + S↓ + Fe 2+ ) remaining in the solution. Filter to obtain sulfur and the third filtrate. During this process, the absorption rate of hydrogen sulfide is higher than 99%.

[0060] (7) Electrolytically regenerate the third filtrate. Add a small amount of hydrochloric acid to adjust the solution to acidic, inhibit the hydrolysis of ferric ions and regulate the conductivity of the solution. Use graphite as the anode and platinum-coated titanium mesh as the cathode. The plate spacing is 15 cm, the electrolytic cell voltage is 2 V, and a DC power supply is used. Ferrous ions are oxidized to ferric ions at the anode (2Fe 2+ →2Fe 3+ +2e - ), remaining in the solution. Hydrogen ions are reduced to hydrogen gas at the cathode (2H + +2e - →H2↑). The hydrogen gas floats to the surface and is collected in the sealed space above the liquid level of the electrolytic cell. The electrolysis temperature is 60 °C, the concentration of ferrous ions is 0.5 mol / L, the hydrogen ion concentration is controlled at about 2.5 mol / L, and an on-line ultraviolet-visible spectrometer is used to detect the Fe³⁺ concentration to ensure that the regeneration efficiency is greater than 95%.

[0061] (8) Use a pump to transport the ferric ion solution obtained by electrolytic regeneration in step 7 back to step (6) for recycling as the absorption liquid for purifying hydrogen sulfide waste gas.

[0062] Example 3 (1) Mix the raw pyrolytic carbon black with water and stir to disperse it to form a pulp, and perform magnetic separation using a wet magnetic separator; the pulp concentration is 150 g / L, the magnetic flux of the magnetic roller is 3000 Gs, the rotational speed of the magnetic roller is 100 r / min, to obtain iron filings and a carbon black pulp product. During this process, the removal rate of iron filings is higher than 95%.

[0063] (2) Under ultrasonic conditions, add hydrobromic acid to the carbon black pulp product after magnetic separation to desalt the waste tire pyrolytic carbon black. After leaching, hydrogen sulfide gas and zinc bromide solution will be generated from the pyrolytic carbon black (ZnS + 2HBr → Zn 2+ +2Br - +H2S↑). During the acid leaching process, the ultrasonic frequency is 50 kHz, the leaching temperature is 60 °C, the leaching time is 90 min, the solid-liquid ratio of the pyrolytic carbon black to the hydrobromic acid solution is 75 g / L, the concentration of hydrobromic acid in the hydrobromic acid solution is 1.0 mol / L. After removing metal salts, the first acid leaching filtrate and the first carbon black product are obtained by filtration. The solid first carbon black product enters the next process. The removal rate of zinc sulfide in this step is higher than 90%.

[0064] (3) Add metal zinc particles to the first acid leaching filtrate to undergo a displacement reaction with hydrogen ions in the filtrate to generate hydrogen gas and zinc bromide (Zn + 2HBr → Zn 2+ +2Br -(+H2↑), the stirring speed is 800 r / min, and the reaction time is 45 min; the pH at the end of the reaction is controlled at about 5.0, and the particle size of the metallic zinc particles is 0.5 mm to 2 mm; the concentration of the metallic zinc particles in the first acid leaching filtrate is 60 g / L. After the reaction is completed, the unreacted metallic zinc particles and the second filtrate are obtained by filtration.

[0065] (4) Heat and evaporate the filtered second filtrate and crystallize it. The evaporation temperature is controlled at 180 °C, and then it is evaporated to 80 °Be, and cooled and crystallized at 20 °C. A centrifuge is used for dehydration, and a drying device is used to dry the solid product of the centrifuge to obtain zinc bromide crystals.

[0066] (5) Configure the zinc bromide crystals obtained in step (4) into a zinc bromide heavy liquid. The solvent used for the zinc bromide heavy liquid is a mixed solution of pure water and absolute ethanol. In the mixed solution of pure water and absolute ethanol, the volume percentage of water is 85%, and the volume percentage of absolute ethanol is 15%. Use the mixed solution of pure water and absolute ethanol to dissolve the zinc bromide crystals, and the density of the heavy liquid is 1.7 g / cm 3 , Add the first carbon black product to the zinc bromide heavy liquid. The liquid-solid mass ratio is 10:1. Ultrasonic for 15 min to promote its dispersion. The ultrasonic frequency is 30 kHz. Then use a centrifuge to accelerate the separation and stratification of carbon particles and silica particles. The centrifugal speed is 2000 r / min, and the centrifugal time is 10 min. Pour out the separated pyrolytic carbon black after stratification to obtain the floating matter - pure carbon black product and the sediment - silica tailings.

[0067] (6) The hydrogen sulfide gas obtained during the acid leaching process in step (2) is inhaled into the ferric ion solution prepared with ferric chloride through a jet mixer. The throat velocity of the jet pipe is 40 m / s. Keep the temperature of the ferric ion solution at 70 °C. The concentration of ferric ions in the ferric ion solution is 1.5 mol / L. Add hydrochloric acid to keep the hydrogen ion concentration at about 1 mol / L to prevent the hydrolysis of ferric ions. The liquid level height of the ferric ion solution is 50 cm. The gas overflowing from the purification pool liquid surface is also inhaled into the jet mixer for secondary absorption. Under these conditions, the hydrogen sulfide gas is oxidized into sulfur and hydrogen ions are produced, and the ferric ions are reduced to ferrous ions (H2S + Fe 3+ → 2H + + S↓ + Fe 2+ ) remains in the solution. Sulfur and the third filtrate are obtained by filtration. During this process, the absorption rate of hydrogen sulfide is higher than 99%.

[0068] (7) Electrolytically regenerate the third filtrate, add a small amount of hydrochloric acid to adjust the solution to acidic, inhibit the hydrolysis of ferric ions and regulate the conductivity of the solution. Use graphite as the anode and platinum-coated titanium mesh as the cathode. The plate spacing is 15 cm, the electrolytic cell voltage is 2 V, and a DC power supply is used. Ferrous ions are oxidized to ferric ions at the anode (2Fe 2+ →2Fe 3+ +2e - ), remaining in the solution, and hydrogen ions are reduced to hydrogen at the cathode (2H + +2e - →H2↑). The hydrogen floats to the surface and is collected in the sealed space above the liquid level of the electrolytic cell. The electrolysis temperature is 60 °C, the concentration of ferrous ions is 0.5 mol / L, the hydrogen ion concentration is controlled at about 2.5 mol / L, and an online ultraviolet-visible spectrometer is used to detect the Fe³⁺ concentration to ensure that the regeneration efficiency is greater than 95%.

[0069] (8) Use a pump to transport the electrolytically regenerated ferric ion solution in step 7 back to step (6) for recycling as the absorption liquid for hydrogen sulfide waste gas purification.

[0070] Example 4 (1) Mix the raw pyrolytic carbon black with water and stir to disperse it to form a pulp, and use a wet magnetic separator for magnetic separation; the pulp concentration is 150 g / L, the magnetic flux of the magnetic roller is 3000 Gs, the rotation speed of the magnetic roller is 100 r / min, to obtain iron filings and a carbon black pulp product. During this process, the removal rate of iron filings is higher than 95%.

[0071] (2) Under ultrasonic conditions, add hydrobromic acid to the carbon black pulp product after magnetic separation to desalt the waste tire pyrolytic carbon black. After leaching, hydrogen sulfide gas and zinc bromide solution will be generated in the pyrolytic carbon black (ZnS + 2HBr → Zn 2+ +2Br - +H2S↑). During the acid leaching process, the ultrasonic frequency is 50 kHZ, the leaching temperature is 60 °C, the leaching time is 90 min, the solid-liquid ratio of the pyrolytic carbon black and the hydrobromic acid solution is 75 g / L, the concentration of hydrobromic acid in the hydrobromic acid solution is 1.5 mol / L. After removing metal salts, the first acid leaching filtrate and the first carbon black product are obtained by filtration. The solid first carbon black product enters the next process. The removal rate of zinc sulfide in this step is higher than 95%.

[0072] (3) Add metal zinc particles to the first acid leaching filtrate to undergo a displacement reaction with hydrogen ions in the filtrate to generate hydrogen and zinc bromide (Zn + 2HBr → Zn 2+ +2Br -(+H2↑), the stirring speed is 800 r / min, and the reaction time is 45 min; the pH at the end of the reaction is controlled at about 5.0, and the particle size of the metallic zinc particles is 0.5 mm to 2 mm; the concentration of the metallic zinc particles in the first acid leaching filtrate is 60 g / L. After the reaction is completed, the unreacted metallic zinc particles and the second filtrate are obtained by filtration.

[0073] (4) Heat and evaporate the filtered second filtrate for crystallization. The evaporation temperature is controlled at 180 °C, and then it is evaporated to 80 °Be, and cooled and crystallized at 20 °C. A centrifuge is used for dehydration, and a drying device is used to dry the solid product of the centrifuge to obtain zinc bromide crystals.

[0074] (5) Configure the zinc bromide crystals obtained in step (4) into a zinc bromide heavy liquid. The solvent used for the zinc bromide heavy liquid is a mixed solution of pure water and absolute ethanol. In the mixed solution of pure water and absolute ethanol, the volume percentage of water is 85%, and the volume percentage of absolute ethanol is 15%. Use the mixed solution of pure water and absolute ethanol to dissolve the zinc bromide crystals, and the density of the heavy liquid is 1.7 g / cm 3 , Add the first carbon black product to the zinc bromide heavy liquid, and the liquid-solid mass ratio is 10:1. Ultrasonic for 15 min to promote its dispersion, the ultrasonic frequency is 30 kHz, and then use a centrifuge to accelerate the separation and stratification of carbon particles and silica particles. The centrifugation speed is 2000 r / min, and the centrifugation time is 10 min. Pour out the separated pyrolytic carbon black after stratification to obtain the floating matter - pure carbon black product and the sediment - silica tailings.

[0075] (6) Inhale the hydrogen sulfide gas obtained during the acid leaching process in step (2) into the ferric ion solution prepared with ferric chloride through a jet mixer. The flow rate at the throat of the jet pipe is 40 m / s, keep the temperature of the ferric ion solution at 70 °C, the concentration of ferric ions in the ferric ion solution is 1.5 mol / L, add hydrochloric acid to keep the hydrogen ion concentration at about 1 mol / L to prevent the hydrolysis of ferric ions, and the liquid level height of the ferric ion solution is 50 cm. The gas overflowing from the liquid level of the purification pool is also inhaled into the jet mixer for secondary absorption. Under these conditions, the hydrogen sulfide gas is oxidized into sulfur and hydrogen ions are produced, and the ferric ions are reduced to ferrous ions (H2S + Fe 3+ → 2H + + S↓ + Fe 2+ ) remains in the solution, and sulfur and the third filtrate are obtained by filtration. During this process, the absorption rate of hydrogen sulfide is higher than 99%.

[0076] (7) Electrolytically regenerate the third filtrate. Add a small amount of hydrochloric acid to adjust the solution to acidic, inhibit the hydrolysis of ferric ions, and regulate the electrical conductivity of the solution. Use graphite as the anode and platinum-coated titanium mesh as the cathode. The plate spacing is 15 cm, the electrolytic cell voltage is 2 V, and a DC power supply is used. Ferrous ions are oxidized to ferric ions at the anode (2Fe 2+ →2Fe 3+ +2e - ), remaining in the solution. Hydrogen ions are reduced to hydrogen gas at the cathode (2H + +2e - →H2↑). The hydrogen gas floats to the surface and is collected in the sealed space above the liquid level of the electrolytic cell. The electrolysis temperature is 60 °C, the ferrous ion concentration is 0.5 mol / L, the hydrogen ion concentration is controlled at about 2.5 mol / L, and an online ultraviolet-visible spectrometer is used to detect the Fe³⁺ concentration to ensure that the regeneration efficiency is greater than 95%.

[0077] (8) Use a pump to transport the electrolytically regenerated ferric ion solution in step 7 back to step (6) for recycling as the absorption liquid for hydrogen sulfide waste gas purification.

[0078] Example 5 (1) Mix the raw pyrolytic carbon black ore with water and stir to disperse it to form a pulp, and use a wet magnetic separator for magnetic separation; the pulp concentration is 150 g / L, the magnetic flux of the magnetic roller is 3000 Gs, the rotation speed of the magnetic roller is 100 r / min, to obtain iron filings and carbon black pulp products. During this process, the removal rate of iron filings is higher than 95%.

[0079] (2) Under ultrasonic conditions, add hydrobromic acid to the carbon black pulp product after magnetic separation to desalt the waste tire pyrolytic carbon black. After leaching, hydrogen sulfide gas and zinc bromide solution will be generated in the pyrolytic carbon black (ZnS + 2HBr → Zn 2+ +2Br - +H2S↑). During the acid leaching process, the ultrasonic frequency is 50 kHz, the leaching temperature is 60 °C, the leaching time is 90 min, the solid-liquid ratio of the pyrolytic carbon black and the hydrobromic acid solution is 75 g / L, the concentration of hydrobromic acid in the hydrobromic acid solution is 2.5 mol / L. After removing metal salts, the first acid leaching filtrate and the first carbon black product are obtained by filtration. The solid first carbon black product enters the next process. The removal rate of zinc sulfide in this step is higher than 98%.

[0080] (3) Add metal zinc particles to the first acid leaching filtrate to undergo a displacement reaction with hydrogen ions in the filtrate to generate hydrogen gas and zinc bromide (Zn + 2HBr → Zn 2+ +2Br -+H2↑), the stirring speed is 800 r / min, and the reaction time is 45 min; the pH at the end of the reaction is controlled at about 5.0, and the particle size of the metallic zinc particles is 0.5 mm - 2 mm; the concentration of the metallic zinc particles in the first acid leaching filtrate is 60 g / L. After the reaction is completed, the unreacted metallic zinc particles and the second filtrate are obtained by filtration.

[0081] (4) Heat and evaporate the filtered second filtrate and crystallize it. The evaporation temperature is controlled at 180 °C, and then it is evaporated to 80 °Be, and cooled and crystallized at 20 °C. Use a centrifuge for dehydration, and use a drying device to dry the solid product of the centrifuge to obtain zinc bromide crystals.

[0082] (5) Configure the zinc bromide crystals obtained in step (4) into a zinc bromide heavy liquid. The solvent used for the zinc bromide heavy liquid is a mixed solution of pure water and absolute ethanol. In the mixed solution of pure water and absolute ethanol, the volume percentage of water is 85%, and the volume percentage of absolute ethanol is 15%. The density of the heavy liquid is 1.7 g / cm 3 , add the first carbon black product to the zinc bromide heavy liquid. The liquid-solid mass ratio is 10:1. Ultrasonic for 15 min to promote its dispersion. The ultrasonic frequency is 30 kHz. Then use a centrifuge to accelerate the separation and stratification of carbon particles and silica particles. The centrifugal speed is 2000 r / min, and the centrifugal time is 10 min. Pour out the separated pyrolytic carbon black after stratification to obtain the floating matter - pure carbon black product, and the sediment - silica tailings.

[0083] (6) Inhale the hydrogen sulfide gas obtained during the acid leaching process in step (2) into the ferric ion solution prepared with ferric chloride through a jet mixer. The flow velocity at the throat of the jet pipe is 40 m / s. Keep the temperature of the ferric ion solution at 70 °C. The concentration of ferric ions in the ferric ion solution is 1.5 mol / L. Add hydrochloric acid to keep the hydrogen ion concentration at about 1 mol / L to prevent the hydrolysis of ferric ions. The liquid level height of the ferric ion solution is 50 cm. The gas overflowing from the liquid level of the purification pool is also inhaled into the jet mixer for secondary absorption. Under these conditions, the hydrogen sulfide gas is oxidized into sulfur and hydrogen ions are produced, and ferric ions are reduced to ferrous ions (H2S + Fe 3+ → 2H + + S↓ + Fe 2+ ) remains in the solution. Filter to obtain sulfur and the third filtrate. During this process, the absorption rate of hydrogen sulfide is higher than 99%.

[0084] (7) Electrolytically regenerate the third filtrate. Add a small amount of hydrochloric acid to adjust the solution to acidic to inhibit the hydrolysis of ferric ions and regulate the conductivity of the solution. Use graphite for the anode and platinum-plated titanium mesh for the cathode. The plate spacing is 15 cm. The voltage of the electrolytic cell is 2 V. Use a DC power supply for power supply. Ferrous ions are oxidized to ferric ions at the anode (2Fe 2+→ 2Fe 3+ + 2e - ), which remains in the solution. Hydrogen ions are reduced to hydrogen gas at the cathode (2H + + 2e - → H2↑). The hydrogen gas floats to the surface and is collected in the sealed space above the liquid level of the electrolytic cell. The electrolysis temperature is 60 °C, the concentration of divalent iron ions is 0.5 mol / L, the hydrogen ion concentration is controlled at about 2.5 mol / L, and an online ultraviolet-visible spectrometer is used to detect the Fe³⁺ concentration to ensure that the regeneration efficiency is greater than 95%.

[0085] (8) Use a pump to transport the trivalent iron ion solution electrolytically regenerated in step 7 back to step (6) for recycling as the absorption liquid for purifying hydrogen sulfide waste gas.

[0086] Example 6 (1) After mixing and stirring the raw pyrolytic carbon black ore with water to form a pulp, magnetic separation is carried out using a wet magnetic separator; the pulp concentration is 50 g / L, the magnetic flux of the magnetic roller is 2000 Gs, the rotational speed of the magnetic roller is 150 r / min, and iron filings and carbon black pulp products are obtained.

[0087] (2) Under ultrasonic conditions, hydrobromic acid is added to the carbon black pulp product after magnetic separation to carry out desalination treatment on waste tire pyrolytic carbon black. After leaching, hydrogen sulfide gas and zinc bromide solution will be generated in the pyrolytic carbon black (ZnS + 2HBr → Zn 2+ + 2Br - + H2S↑). During the acid leaching process, the ultrasonic frequency is 80 kHz, the leaching temperature is 30 °C, the leaching time is 30 min, the solid-liquid ratio of the pyrolytic carbon black and the hydrobromic acid solution is 50 g / L, the concentration of hydrobromic acid in the hydrobromic acid solution is 0.2 mol / L. After removing the metal salt, the first acid leaching filtrate and the first carbon black product are obtained by filtration. The solid first carbon black product enters the next process, and the zinc sulfide removal rate in this step is higher than 40%.

[0088] (3) Metal zinc particles are added to the first acid leaching filtrate to undergo a displacement reaction with hydrogen ions in the filtrate to generate hydrogen gas and zinc bromide (Zn + 2HBr → Zn 2+ + 2Br - + H2↑). The stirring speed is 300 r / min, and the reaction time is 150 min; the pH at the end of the reaction is controlled at about 2.5, and the particle size of the metal zinc particles is 0.5 mm - 2 mm; the concentration of the metal zinc particles in the first acid leaching filtrate is 30 g / L. After the reaction is completed, the unreacted metal zinc particles and the second filtrate are obtained by filtration.

[0089] (4) Heat and evaporate the filtered second filtrate for crystallization. Control the evaporation temperature at 120 °C, then evaporate until it reaches 50 °Be, and cool and crystallize at 10 °C. Use a centrifuge for dehydration and a drying device to dry the solid product of the centrifuge to obtain zinc bromide crystals.

[0090] (5) Configure the zinc bromide crystals obtained in step (4) into a zinc bromide heavy liquid. The solvent used for the zinc bromide heavy liquid is a mixed solution of pure water and absolute ethanol. In the mixed solution of pure water and absolute ethanol, the volume percentage of water is 85% and the volume percentage of absolute ethanol is 15%. The density of the heavy liquid is 1.2 g / cm 3 , add the first carbon black product to the zinc bromide heavy liquid. The liquid-solid mass ratio is 2:1. Ultrasonic for 15 min to promote its dispersion. The ultrasonic frequency is 20 kHz. Then use a centrifuge to accelerate the separation and stratification of carbon particles and silica particles. The centrifugal speed is 3000 r / min and the centrifugal time is 3 min. Pour out the separated pyrolytic carbon black layer by layer to obtain the floating matter - pure carbon black product and the sediment - silica tailings.

[0091] (6) Inhale the hydrogen sulfide gas obtained during the acid leaching process in step (2) into the ferric ion solution prepared with ferric chloride through a jet mixer. The flow velocity at the throat of the jet pipe is 40 m / s. Keep the temperature of the ferric ion solution at 25 °C. The concentration of ferric ions in the ferric ion solution is 0.1 mol / L. Add hydrochloric acid to keep the hydrogen ion concentration at 0.5 mol / L to prevent the hydrolysis of ferric ions. The liquid level height of the ferric ion solution is 30 cm. The gas overflowing from the liquid level of the purification tank is also inhaled into the jet mixer for secondary absorption. Under these conditions, oxidize the hydrogen sulfide gas into sulfur and produce hydrogen ions, and the ferric ions are reduced to ferrous ions (H2S + Fe 3+ → 2H + + S↓ + Fe 2+ ) remaining in the solution, and filter to obtain sulfur and the third filtrate.

[0092] (7) Electrolytically regenerate the third filtrate. Add a small amount of hydrochloric acid to adjust the solution to acidic, inhibit the hydrolysis of ferric ions and regulate the conductivity of the solution. Use graphite for the anode and platinum-plated titanium mesh for the cathode. The plate spacing is 15 cm. The voltage of the electrolytic cell is 0.5 V. Use a DC power supply for power supply. Ferrous ions are oxidized to ferric ions at the anode (2Fe 2+ → 2Fe 3+ + 2e - ) remaining in the solution, and hydrogen ions are reduced to hydrogen gas at the cathode (2H + + 2e -→H2↑), hydrogen gas floats to the water surface and is collected in the sealed space above the liquid level of the electrolytic cell. The electrolysis temperature is 40 °C, the concentration of divalent iron ions is 2.5 mol / L, the hydrogen ion concentration is controlled at about 6 mol / L, and an online ultraviolet-visible spectrometer is used to detect the Fe³⁺ concentration to ensure that the regeneration efficiency is greater than 95%.

[0093] (8) Use a pump to transport the trivalent iron ion solution electrolytically regenerated in step 7 back to step (6) for recycling as the absorption liquid for purifying hydrogen sulfide waste gas.

[0094] Example 7 (1) Mix the raw pyrolytic carbon black with water and stir to disperse it to form a pulp, and use a wet magnetic separator for magnetic separation; the pulp concentration is 200 g / L, the magnetic flux of the magnetic roller is 8000 Gs, the rotational speed of the magnetic roller is 80 r / min, and iron filings and carbon black pulp products are obtained.

[0095] (2) Under ultrasonic conditions, add hydrobromic acid to the carbon black pulp product after magnetic separation to perform desalination treatment on waste tire pyrolytic carbon black. After leaching, hydrogen sulfide gas and zinc bromide solution will be generated from the pyrolytic carbon black (ZnS + 2HBr → Zn 2+ + 2Br - + H2S↑). During the acid leaching process, the ultrasonic frequency is 30 kHz, the leaching temperature is 90 °C, the leaching time is 150 min, the solid-liquid ratio of the pyrolytic carbon black and the hydrobromic acid solution is 200 g / L, the concentration of hydrobromic acid in the hydrobromic acid solution is 5 mol / L, and after removing metal salts, the first acid leaching filtrate and the first carbon black product are obtained by filtration. The solid first carbon black product enters the next process, and the zinc sulfide removal rate in this step is higher than 90%.

[0096] (3) Add metal zinc particles to the first acid leaching filtrate to undergo a displacement reaction with hydrogen ions in the filtrate to generate hydrogen gas and zinc bromide (Zn + 2HBr → Zn 2+ + 2Br - + H2↑), the stirring speed is 2000 r / min, and the reaction time is 15 min; the pH at the end of the reaction is controlled at about 6.5, the particle size of the metal zinc particles is 0.5 mm to 2 mm; the concentration of the metal zinc particles in the first acid leaching filtrate is 140 g / L, and after the reaction is completed, the unreacted metal zinc particles and the second filtrate are obtained by filtration.

[0097] (4) Heat and evaporate and crystallize the filtered second filtrate, control the evaporation temperature at 250 °C, then evaporate to 100 °Be, cool and crystallize at 40 °C, use a centrifuge for dehydration, and use a drying device to dry the solid product of the centrifuge to obtain zinc bromide crystals.

[0098] (5) Prepare the zinc bromide crystals obtained in step (4) into a zinc bromide heavy liquid. The solvent used for the zinc bromide heavy liquid is a mixed solution of pure water and absolute ethanol. In the mixed solution of pure water and absolute ethanol, the volume percentage of water is 85% and the volume percentage of absolute ethanol is 15%. The density of the heavy liquid is 2.2 g / cm 3 , Add the first carbon black product to the zinc bromide heavy liquid. The liquid-solid mass ratio is 30:1. Ultrasonic for 15 min to promote its dispersion. The ultrasonic frequency is 50 kHZ. Then use a centrifuge to accelerate the separation and stratification of carbon particles and silica particles. The centrifugal speed is 6000 r / min and the centrifugal time is 25 min. Pour out the separated pyrolytic carbon black layer by layer to obtain the floating matter - pure carbon black product and the sediment - silica tailings.

[0099] (6) The hydrogen sulfide gas obtained during the acid leaching process in step (2) is inhaled into the ferric ion solution prepared with ferric chloride through a jet mixer. The flow rate at the throat of the jet pipe is 40 m / s. Keep the temperature of the ferric ion solution at 80 °C. The concentration of ferric ions in the ferric ion solution is 2.5 mol / L. Add hydrochloric acid to keep the hydrogen ion concentration at 6 mol / L to prevent the hydrolysis of ferric ions. The liquid level height of the ferric ion solution is 150 cm. The gas overflowing from the purification pool liquid surface is also inhaled into the jet mixer for secondary absorption. Under these conditions, the hydrogen sulfide gas is oxidized into sulfur and hydrogen ions are produced. Ferric ions are reduced to ferrous ions (H2S + Fe 3+ → 2H + + S↓ + Fe 2+ ) remain in the solution. Filter to obtain sulfur and the third filtrate.

[0100] (7) Electrolytically regenerate the third filtrate. Add a small amount of hydrochloric acid to adjust the solution to acidic to inhibit the hydrolysis of ferric ions and control the conductivity of the solution. Use graphite for the anode and platinum-coated titanium mesh for the cathode. The plate spacing is 15 cm. The electrolytic cell voltage is 3 V. Use a DC power supply. Ferrous ions are oxidized to ferric ions at the anode (2Fe 2+ → 2Fe 3+ + 2e - ) remain in the solution. Hydrogen ions are reduced to hydrogen gas at the cathode (2H + + 2e - → H2↑). The hydrogen gas floats to the water surface and is collected in the sealed space above the electrolytic cell liquid surface. The electrolysis temperature is 80 °C. The ferrous ion concentration is 0.1 mol / L. Control the hydrogen ion concentration at about 0.5 mol / L. Use an online ultraviolet-visible spectrometer to detect the Fe³⁺ concentration to ensure that the regeneration efficiency is greater than 95%.

[0101] (8) Use a pump to transport the electrolytically regenerated ferric ion solution in step 7 back to step (6) for recycling and use it as the absorption liquid for hydrogen sulfide waste gas purification.

[0102] Figure 2 Examples 1 to 5 of the purification of pyrolytic carbon black by acid leaching with hydrobromic acid show the effects of different hydrobromic acid concentrations on the ash content of pyrolytic carbon black. From Figure 2 It can be seen that as the concentration of hydrobromic acid increases, the ash content of pyrolytic carbon black decreases significantly. When the concentration reaches 2.0 mol / L, the ash content no longer changes, indicating that zinc salts and calcium salt impurities in pyrolytic carbon black can be completely removed by 2 mol / L hydrobromic acid.

[0103] Figure 3 Figure 10 is the XRD comparison chart of pyrolytic carbon black before and after leaching in Example 1. From Figure 3 It can be seen that there are obvious differences between the raw ore of pyrolytic carbon black after magnetic separation and the first carbon black product. The characteristic peaks of zinc salts and calcium salts disappear significantly after acid leaching with hydrobromic acid, indicating that these two impurities have been removed by hydrobromic acid.

[0104] Figure 4 Figure 11 is the XRD analysis chart of the first carbon black product, pure carbon black product and silica tailings in Example 1. From Figure 4 It can be seen that there are significant differences in the XRD patterns of the pure carbon black product, silica tailings and the first carbon black product. The characteristic peak of SiO2 in the silica tailings as the gravity separation heavy product is significantly higher than that in the gravity separation feed (the first carbon black product) and the gravity separation float (pure carbon black product). The characteristic peak of SiO2 in the pure carbon black product as the gravity separation float almost disappears, indicating that after the first carbon black product is separated by zinc bromide heavy liquid, SiO2 is significantly enriched in the gravity separation heavy product.

[0105] The method of the present invention is simple to operate, has a short process flow, and the by-product zinc bromide generated during the purification of pyrolytic carbon black can be used as a gravity separation medium. The acid leaching waste gas is converted into sulfur and hydrogen, and the ferric ion absorption liquid can be recycled and regenerated. This process not only perfectly fits the modern industrial concept of cost reduction, efficiency improvement and sustainable development, but also achieves the expected effects of full enclosure and zero emission in the whole process flow, realizing the full-component recovery of pyrolytic carbon black.

[0106] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0107] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A method for upgrading and purifying carbon black obtained from pyrolysis of waste tires, characterized in that, It includes the following steps: Wet magnetic separation is carried out on waste tire pyrolytic carbon black to remove iron filings, and the pyrolytic carbon black after magnetic separation is obtained; The pyrolytic carbon black after magnetic separation and hydrobromic acid are mixed for acid leaching. Metal salts are removed during the acid leaching process to obtain hydrogen sulfide gas, the first acid leaching filtrate and the first carbon black product; Zinc particles are added to the first acid leaching filtrate, and a displacement reaction occurs to obtain hydrogen gas, unreacted zinc particles and the second filtrate; The second filtrate is evaporated and crystallized to obtain zinc bromide; A solvent is added to zinc bromide to prepare a heavy liquid, and the first carbon black product is reselected to obtain a pure carbon black product and a silica tailing; Hydrogen sulfide gas is introduced into a ferric ion solution for purification and absorption. During the purification and absorption process, hydrogen sulfide is oxidized to sulfur and hydrogen ions are generated, and ferric ions are reduced to ferrous ions. After the purification and absorption is completed, sulfur and the third filtrate are obtained by filtration; The third filtrate is subjected to electrolytic regeneration. During the electrolytic regeneration process, ferrous ions are oxidized to ferric ions at the anode, and hydrogen ions are reduced to hydrogen gas at the cathode. After the electrolytic regeneration is completed, a regenerated ferric ion solution and hydrogen gas are obtained, and the regenerated ferric ions are recycled in the purification and absorption step; 2. The method for upgrading and purifying carbon black obtained by cracking waste tires according to claim 1, wherein In the acid leaching step, the concentration of hydrobromic acid is 0.2 mol / L to 5 mol / L, the concentration of the pyrolytic carbon black after magnetic separation in hydrobromic acid is 50 g / L to 200 g / L, the leaching temperature is 30 °C to 90 °C, the leaching time is 30 min to 150 min, and the ultrasonic frequency of acid leaching is 30 kHz to 80 kHz.

3. A method for upgrading and purifying waste tire pyrolysis carbon black according to claim 1, characterized in that, During reselection, the mass ratio of the heavy liquid to the first carbon black product is 2 to 30:1, the ultrasonic frequency is 20 kHz to 50 kHz, and the ultrasonic time is 5 min to 25 min.

4. A method for upgrading and purifying waste tire pyrolysis carbon black according to claim 1, characterized in that, The centrifugal speed for reselection is 600 r / min to 3000 r / min, and the centrifugal time is 3 min to 25 min.

5. A method for upgrading and purifying carbon black obtained from pyrolysis of waste tires according to claim 1, characterized in that, The density of the heavy liquid is 1.2 g / cm 3 ~3.2 g / cm 3 , and the solvent is one or more of water, organic solvents, alkaline cleaning agents, acidic cleaning agents, biological enzyme cleaning agents, surfactants, and degreasing agent solutions.

6. A method for upgrading and purifying waste tire pyrolysis carbon black according to claim 1, characterized in that, During wet magnetic separation, water is added to the waste tire pyrolytic carbon black to obtain a pulp; the pulp concentration is 50 g / L to 200 g / L, the magnetic flux of the magnetic roller is 2000 Gs to 8000 Gs, and the rotational speed of the magnetic roller is 80 r / min to 150 r / min.

7. A method for upgrading and purifying carbon black obtained from pyrolysis of waste tires according to claim 1, wherein, In the displacement reaction, the stirring speed is 300 r / min to 2000 r / min, the reaction time is 15 min to 150 min; the pH is 2.5 to 6.5, the particle size of the metallic zinc particles is 0.2 mm to 3 mm; the solid-liquid ratio of the zinc particles to the filtrate A is 30 g / L to 140 g / L.

8. A method for upgrading and purifying waste tire pyrolysis carbon black according to claim 1, characterized in that, The evaporation and crystallization steps are: the evaporation temperature is 120 °C to 250 °C, and then it is evaporated to 50 °Be to 100 °Be, and cooled and crystallized at 10 °C to 40 °C.

9. A method for upgrading and purifying waste tire pyrolysis carbon black according to claim 1, characterized in that, In the purification and absorption step, the reaction temperature is 25 °C to 80 °C, the ferric ion concentration is 0.1 mol / L to 2.5 mol / L, the hydrogen ion concentration in the ferric ion solution is 0.5 mol / L to 6 mol / L, the liquid level height of the ferric ion solution is 30 cm to 150 cm, and the ferric ion solution is a mixture of an iron source containing ferric ions and an acid, a mixture of an iron source containing ferric ions and an oxidant, or a mixture of an iron source containing ferric ions, an acid and an oxidant.

10. A method for upgrading and purifying waste tire pyrolysis carbon black according to claim 1, characterized in that, During the electrolytic regeneration process, the electrolytic temperature is 40°C to 80°C, the electrolytic voltage is 0.5V to 3V, the concentration of divalent iron ions is 0.1mol / L to 1.5mol / L, and the hydrogen ion concentration is 0.5mol / L to 3mol / L.

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