CN111826526A - Method and device for environmental protection recovery of precious metals in waste circuit boards by combined smelting of waste circuit boards, copper concentrate and desulfurization gypsum - Google Patents

Abstract

The invention discloses a method and a device for a combined smelting of waste circuit boards, copper concentrate and desulfurization gypsum for environmental protection and recycling of precious metals in waste circuit boards. After the impurities such as copper wire are crushed, they are mixed with copper concentrate, copper concentrate auxiliary materials and desulfurized gypsum for granulation, and then added to the furnace for smelting. During the smelting process, dioxin is generated by the reaction of desulfurized gypsum and other chemical components in the furnace. Ying inhibitor to inhibit the generation of dioxins; after the smelting flue gas is recovered by waste heat, electrostatic precipitator, and then subjected to sulfuric acid absorption, polluted acid desulfurization and other procedures to generate polluted acid desulfurized gypsum, which is returned to the granulation process for cyclic granulation to achieve the purpose of resource recycling and utilization. The method of the invention can self-generate dioxin inhibitors, solve the problem of dioxins generated when waste circuit boards and copper concentrate are mixed and smelted, and at the same time, the polluted acid desulfurization gypsum produced in the process of smelting flue gas acid production can be used as a resource. The purpose of energy saving and emission reduction is truly achieved.

Description

Waste circuit board, copper concentrate, desulfurization gypsum combined smelting environmental protection recycling waste circuit board is expensive Metal method and device

technical field

The invention relates to a method and device for combined smelting of waste circuit boards, copper concentrate and desulfurization gypsum for environmental protection and recovery of precious metals in waste circuit boards, and belongs to the technical field of joint development and application of electronic industry waste and metallurgical industry.

Background technique

With the scrapping of a large number of household appliances, the number of waste circuit boards is increasing. The recycling of waste circuit boards is a new industry, and its recycling value has also attracted the attention of many investors and has become a promising industry. The components of waste circuit boards are complex and difficult to recycle. During the combustion process, it is easy to generate dioxins. Dioxin is a highly toxic special organic compound, which has become an important factor restricting the recovery and utilization of secondary resources containing organic substances such as waste circuit boards.

At present, it is known that there are usually two formation mechanisms of dioxins during the high-temperature treatment of waste circuit boards:

(1) Incomplete combustion (high temperature gas phase reaction)

During the high temperature treatment of waste circuit board organic components, incomplete combustion products (PIC) are generated due to insufficient combustion, and the organic chlorine and part of the inorganic chlorine contained in the halogen flame retardant in the organic resin will be released in the form of HCl, and part of the HCI will be released. Converted to Cl and Cl ₂ , which in turn can chlorinate PIC as a source of chlorine. During the combustion process, the oxidation reaction and chlorination reaction of incomplete combustion products are competing reactions. When the chlorination reaction is more likely to occur, PIC generates chlorinated PIC, which then generates PCDD/Fs through the polymerization reaction. It is generally believed that PIC mainly includes aliphatic or alkene and alkyne compounds through chlorination to generate chlorobenzene, and then chlorobenzene is converted into polychlorinated biphenyls. In the combustion zone, the reaction generates PCDFs, and some PCDFs are further reacted to generate PCDDs.

(2) Secondary generation of dioxin after combustion (low temperature heterogeneous catalytic reaction)

There are usually two ways of secondary generation of dioxin after combustion. The first method is called "de novo synthesis", that is, the macromolecular carbon in fly ash (so-called residual carbon) is combined with organic or inorganic chlorine at low temperature (250~350 ° C), through transition metals such as Cu, Fe, etc. Its oxides and other catalytic components catalyze the formation of PCDD/Fs. The second method is "precursor synthesis", that is, at 200°C to 500°C, under the action of catalysts such as CuCl ₂ and FeCl ₃ , incomplete combustion and heterogeneous catalytic reaction on the surface of fly ash can form compounds such as polychlorinated compounds. Various organic precursors such as benzene and chlorophenol are used to generate PCDD/Fs from these precursors. According to the reaction conditions, the secondary generation of dioxin usually occurs in the low temperature zone in the waste circuit board smelting furnace or in the flue matching the furnace body.

In order to control the generation of dioxins, the following measures can be taken when waste circuit boards are treated at high temperature:

(a) Optimizing the combustion process. Usually, as long as the combustion temperature is kept above 850°C, the combustion zone forms sufficient turbulence during the secondary air supply, and the residence time in the high temperature zone is greater than 2s, the combustion can be considered complete. Generally speaking, if three principles are satisfied in the structure, the combustion will be complete, and the dioxin precursors and dioxins generated by incomplete combustion will be reduced accordingly from the combustion area.

(b) Addition of inhibitors. There are three main types of dioxin inhibitors: S and S-containing compounds, nitrogen compounds, and basic compounds. Among the above three types of inhibitors, it is generally believed that the inhibitory ability of S and S-containing compounds on dioxins is higher than that of the other two types of compounds. Sulfur suppression technology mainly controls the generation of dioxins by consuming Cl ₂ in the atmosphere, reacting with metal catalysts in fly ash to reduce catalyst activity, and sulfonating phenolic precursors.

(c) Rapid cooling of flue gas. Reduce the residence time of flue gas in the secondary synthesis temperature region of dioxin and avoid low temperature heterogeneous catalytic reaction.

The smelter of Daye Nonferrous Metals Co., Ltd. (hereinafter referred to as Daye Smelter) adopted the Ausmelt oxygen-enriched top-blown smelting furnace with copper concentrate to process waste circuit boards in 2014. This furnace type optimizes the above (a) combustion process and can meet the "3T" principle of preventing dioxin formation, namely: maintain the high temperature in the furnace (Temperature); prolong the residence time of the gas in the high temperature area (Time); strengthen the furnace The airflow is turbulent, which promotes the diffusion and mixing of air and smoke (Turbulence). At the same time, the supporting quenching scrubbing flue gas treatment technology can avoid the above-mentioned (c) low-temperature heterogeneous catalytic reaction. However, this method has great risks. (a) optimization of the combustion process and (c) rapid cooling of the flue gas only reduces the generation of dioxins to a certain extent. Can be regenerated. Therefore, it is safer to add inhibitors to stop the dioxin-producing reaction.

Aiming at the above (b) means of adding inhibitors to control the generation of dioxins, Chinese patent CN105080325A discloses a method for inhibiting the generation of dioxins in the incineration flue gas of solid wastes. The invention is used when the incineration flue gas is cooled to 500~450 ℃. , the flue gas is introduced into the suppression reactor, and the copper chloride in the flue gas reacts with the inhibitor to be converted into copper metaphosphate, thereby losing the activity of catalyzing the generation of dioxins. The invention additionally adds a suppressing reactor device, the flue gas cooling is not easy to grasp and control, and the applicability is not strong, especially it is not suitable for the large-scale pyro-melting furnace process.

Based on the above reasons, the existing process methods and process equipment for mixing and smelting waste circuit boards and copper concentrates in a certain proportion cannot be practically applied in industrial production. Therefore, the existing process equipment and process methods are improved to make waste Circuit boards can directly participate in the mixed smelting process with copper concentrate, and it is of great significance to directly recycle valuable metals in waste circuit boards.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problem that the production of dioxins cannot be completely suppressed when the existing waste circuit boards and copper concentrates are smelted and burned to recover valuable metals in a certain proportion, resulting in that the process cannot be practically applied in industrial production. A method and a device for recycling precious metals in waste circuit boards through combined smelting of waste circuit boards, copper concentrate and desulfurization gypsum. The method of the invention can self-generate the above-mentioned dioxin inhibitor, and does not need to increase the technological process and purchase additional inhibitors, and at the same time, it can also utilize the foul acid desulfurization gypsum produced in the process of smelting flue gas acid production for resource utilization, which truly achieves energy saving and reduction. purpose of the row.

The method for combined smelting of waste circuit boards, copper concentrate and desulfurized gypsum of the present invention for environmental protection and recycling of precious metals in waste circuit boards comprises the following steps:

(1) Preparation of waste circuit boards: dismantle the waste circuit boards, remove impurities such as tin, iron, aluminum, copper wire, etc., and crush them into copper-containing waste circuit boards with a size of 20~50mm by a crusher;

(2) Mixed granulation: Add copper-containing waste circuit boards together with copper concentrate, desulfurization gypsum, and copper concentrate auxiliary materials into the granulator to make 5-25mm granules. The copper-containing waste circuit boards: The mass ratio of copper concentrate: desulfurization gypsum: copper concentrate auxiliary materials is 5~10:150~180:10~15:20~30;

(3) Oxygen furnace smelting: put the above-prepared pellets into Osmelt furnace for smelting. During the smelting process, the air volume of the lance is controlled at 15000~18000Nm ³ /h and the oxygen flow rate is 25000~ 35000Nm ³ /h, keep the temperature of the molten pool in the smelting furnace at 1180~1310℃, and continue to flow 1000~5000Nm ³ /h of air into the furnace through the secondary tuyere on the secondary combustion chamber of the flue gas, so that the The residence time of the flue gas in the secondary combustion chamber of the flue gas is prolonged by 1~5 seconds, the temperature of the flue gas in the furnace reaches 1100~1310℃, and the organic dioxin content in the flue gas is 0.01~0.04 ng TEQ/m ³ ; The high temperature flue gas is concentrated in the flue and transported to the waste heat boiler for waste heat recovery;

(4) Valuable metal recovery: after the melt produced by the smelting furnace flows out through the liquid outlet at the lower part of the furnace body, electric furnace sedimentation, converter smelting, refining furnace refining and extraction of copper and copper anode slime are successively carried out to recover gold, silver, platinum and palladium;

(5) Recovery of smelting flue gas: the flue gas after waste heat recovery is dedusted by the flue gas purification device, and then enters the concentrated sulfuric acid absorption tower to produce sulfuric acid. After acid production, the exhaust gas enters the exhaust absorption tower for absorption, and the detected dioxin content is 0.011~ 0.023 ng TEQ/m ³ , which meets the discharge standard, and is directly evacuated; the sulfuric acid obtained by absorption contains many heavy metal ions, which is added to the sewage acid impurity removal tank, and quicklime is added for impurity removal and filtration, and the obtained filtrate is purified by sulfuric acid. The impurity removal system prepares concentrated sulfuric acid, and the main component in the obtained filter residue is desulfurized gypsum, which is added to the desulfurized gypsum dryer and dried to a moisture content of ≤15%, and then added to step (2) for recycling, granulation and recovery of valuable metals .

The structure of the ultra-oxygen-enriched spray gun used in the step (3) of the present invention has been disclosed in the inventor's prior patent CN111206157A, and its structure is made of four concentric steel cylinders, which extend from the inside to the The pulverized coal, oxygen, lance air and sleeve air are fed in sequence, and the air inlets for oxygen, lance air and sleeve air are opened on the side walls of the concentric steel cylinder in turn.

The copper content in the copper-containing waste circuit board described in the present invention is 10-30%. Of course, it is also possible for waste circuit boards with higher copper content to be used in the method of the present invention, and the smelting effect will be better.

The copper concentrate described in the present invention includes mixed low-sulfur ore and mixed high-sulfur ore, wherein the mixed low-sulfur ore has a copper content of 18-25%, and the mixed high-sulfur ore has a copper content of 20-30%. The proportion of sulfur ore in copper concentrate is not more than 50%.

The copper concentrate auxiliary material in the present invention is composed of one or more of coke, slag concentrate, soot, quartz stone, limestone and coal.

The device used in the method for combined smelting of waste circuit boards, copper concentrate and desulfurized gypsum in the present invention for environmental protection recovery of precious metals in waste circuit boards includes a waste circuit board crusher, in particular: a belt conveyor is provided in front of the waste circuit board crusher The waste circuit board crusher is equipped with a disc granulator, and there are four feeding hoppers above the disc granulator, which are copper concentrate feeding hopper, waste circuit board feeding hopper, copper concentrate auxiliary material feeding hopper and Desulfurized gypsum feeding hopper; after the above four raw materials are granulated by the disc granulator, they are sent to the Osmelt furnace for smelting by the belt conveyor. Precious metals; after the Osmet furnace are sequentially provided with a waste heat recovery boiler, a flue gas purification room, a sulfuric acid absorption tower, a dirty acid removal tank, a dirty acid filter and a desulfurized gypsum dryer. The Osmet furnace smelting produces After the waste heat is recovered by the waste heat recovery boiler, the flue gas enters the flue gas purification room for purification, and then enters the sulfuric acid absorption tower to absorb sulfur dioxide and sulfur trioxide to produce sulfuric acid. After adding quicklime for impurity removal, put it into a dirty acid filter for filtration, and the resulting filter residue is put into a desulfurized gypsum dryer for drying, and then returned to the desulfurized gypsum hopper above the disc granulator for circulation. For the use of ingredients, the connecting pipes between the above devices are equipped with pumps and valves as required.

The sulfuric acid absorption tower in the present invention is also connected with a tail gas absorption tower for absorbing untreated sulfur dioxide tail gas.

The waste circuit board crusher in the present invention is also provided with a dust collection device above the crusher, which is used to collect and centrally process the dust generated by the crusher.

The desulfurization gypsum used in the present invention is the solid waste in the current smelting system flue gas scrubbing acid production, which is produced by adding quicklime to the dirty acid to remove impurities. The resource utilization of desulfurized gypsum has been a hot research topic in recent years.

The principle of the present invention is:

Desulfurized gypsum is mixed with waste circuit boards, copper concentrate, coke and other auxiliary materials and put into the oxygen-enriched top-blown smelting furnace. The following reactions will occur in the low temperature zone below 500 °C:

2C + O ₂ ↑ = 2CO ↑;

CaSO ₄ + 4CO↑ = CaS + 4CO↑;

CaSO ₄ + 2C = CaS + 2CO ₂ ↑;

2CaS + 3O ₂ = 2CaO+2SO ₂ ↑;

The waste circuit board substrate contains epoxy resin. The inorganic chlorine and organic chlorine in the epoxy resin will generate HCl during combustion, and part of the HCl will be converted into Cl and Cl ₂ , which will synthesize dioxins as a chlorine source. The generated CaO can remove the HCl in the flue gas and convert it into CaCl ₂ , which is mixed with the matte slag, and the reaction is as follows:

CaO + 2HCl = CaCl ₂ + H ₂ O;

At the same time, the generated SO ₂ converts Cl ₂ in the flue gas into HCl, eliminating the chlorine source for the secondary reaction of dioxins, and also converting CuO into CuSO ₄ , passivating the CuO catalyst that generates dioxins, thereby inhibiting the The main chemical equations involved in the de novo synthesis of dioxin in the low temperature region are as follows:

Cl ₂ + SO ₂ +H ₂ O = 2HCl + SO ₃ ;

CuO + SO ₂ + 1/2O ₂ = CuSO ₄ ;

It can be seen from the above reactions that the present invention can self-generate calcium oxide and sulfur dioxide as dioxin inhibitors without adding additional dioxin inhibitors, thereby achieving the purpose of compounding environmental protection requirements for dioxin emissions.

Compared with the prior art, the present invention has the following advantages:

(1) There is no need to add additional inhibitors, saving the cost of dioxin control in flue gas production;

(2) A large number of solid wastes in the smelting industry can be properly disposed of with acid desulfurization gypsum, so as to achieve the purpose of resource recycling;

(3) The original production process does not need to be changed, the operation is simple, the practicability is strong, and it can be applied to the large-scale pyrolysis furnace process.

The method and device provided by the invention can be applied to the large-scale pyro-smelting furnace process to suppress the smelting of waste circuit boards, and can self-generate inhibitors, suppress the generation of flue gas dioxins, and do not need to increase the process flow and purchase additional inhibitors. The waste desulfurization gypsum can also be used for resource utilization, which can truly achieve the purpose of energy saving and emission reduction, and is suitable for widespread use.

Description of drawings

FIG. 1 is a schematic diagram of the connection of the device of the present invention.

In the picture: 1—belt conveyor, 2—waste circuit board crusher, 3—disc granulator, 4—copper concentrate feeding hopper, 5—waste circuit board feeding hopper, 6—copper concentrate auxiliary material feeding hopper, 7—Desulphurization gypsum feeding hopper, 8—Osmet furnace, 9—Waste heat recovery boiler, 10—Fume purification chamber, 11—Sulfuric acid absorption tower, 12—Stainless acid impurity removal tank, 13—Stain acid filter, 14 - Desulfurized gypsum dryer, 15 - connecting pipeline, 16 - pump, 17 - valve, 18 - tail gas absorption tower, 19 - dust collection device.

Detailed ways

Example 1

Referring to Fig. 1, a method for environmental protection and recycling of precious metals in waste circuit boards by combined smelting of waste circuit boards, copper concentrate and desulfurized gypsum includes the following steps:

(1) Preparation of waste circuit boards: disassemble the waste circuit boards, remove impurities such as tin, iron, aluminum, copper wires, etc., and crush them into 40mm copper-containing waste circuit boards by the waste circuit board crusher 2;

(2) Mixed granulation: Add copper-containing waste circuit boards together with copper concentrate, desulfurization gypsum, and copper concentrate auxiliary materials into disc granulator 3 to make 10mm-sized granules. The copper-containing waste circuit boards : The mass ratio of copper concentrate: desulfurization gypsum: copper concentrate auxiliary materials is 8:160:12:25;

(3) Oxygen furnace smelting: put the above-prepared pellets into Osmelt furnace 8 for smelting (the feeding amount is 200t/h, the same below). During the smelting process, the air volume of the lance is controlled by the ultra-oxygen-enriched lance at 17000Nm ³ /h, the oxygen flow rate is 30000Nm ³ /h, the temperature of the molten pool in the smelting furnace is kept at 1200~1300℃, and 4000Nm ³ / h air, the residence time of the flue gas in the secondary combustion chamber of the flue gas is prolonged by 3~4 seconds, the flue gas temperature in the furnace reaches 1200~1300 ℃, and the organic dioxin content in the flue gas is 0.036~0.040 ng TEQ/m ³ ; The high-temperature flue gas generated by the smelting furnace is concentrated through the flue and transported to the waste heat boiler for waste heat recovery;

(4) Valuable metal recovery: After the melt produced by the smelting furnace flows out through the liquid outlet at the lower part of the furnace body, the electric furnace sedimentation, converter smelting, refining furnace refining and extraction of copper and copper anode slime are successively carried out to recover gold, silver, platinum and palladium (Fig. not shown);

(5) Recovery of smelting flue gas: the flue gas after waste heat recovery is dedusted by the flue gas purification device 10, and then enters the concentrated sulfuric acid absorption tower 11 to produce sulfuric acid. It is 0.011~0.023 ngTEQ/m ³ , which meets the emission standard and is directly evacuated (Recycling Non-ferrous Metal Industry Pollutant Emission Standard (Draft for Comment)) The emission limit of dioxins for existing enterprises' air pollutants is 1.0 ng· TEQ/m ³ , the emission limit of air pollutants dioxins in new enterprises is 0.5 ng·TEQ/m ³ . After adding polluted acid desulfurization gypsum, the emission concentration of dioxins is less than the limit of 0.5ng·TEQ/m ³ . The dioxin in the exhaust gas discharged by the invention is far lower than this limit); the sulfuric acid obtained by absorption contains more heavy metal ions, which is added to the dirty acid impurity removal tank, and quicklime is added to remove impurities and filter, and the obtained filtrate enters the sulfuric acid The refining and impurity removal system prepares concentrated sulfuric acid, and the main component in the obtained filter residue is desulfurized gypsum, which is added to the desulfurized gypsum dryer and dried to a moisture content of ≤15%, and then added to step (2) for recycling, granulation, and recovery of valuable Metal.

The structure of the ultra-oxygen-enriched spray gun used in the step (3) of the present invention has been disclosed in the inventor's prior patent CN111206157A, and its structure is made of four concentric steel cylinders, which extend from the inside to the The pulverized coal, oxygen, lance air and sleeve air are fed in sequence, and the air inlets for oxygen, lance air and sleeve air are opened on the side walls of the concentric steel cylinder in turn. The same below.

The copper content in the copper-containing waste circuit board described in the present invention is 28%.

The copper concentrate described in the present invention includes mixed low-sulfur ore and mixed high-sulfur ore, wherein the copper content of the mixed low-sulfur ore is 24%, the copper content of the mixed high-sulfur ore is 28%, and the mixed low-sulfur ore is in copper The proportion in the concentrate is 50%.

The copper concentrate auxiliary material in the present invention is composed of coke, quartz stone and limestone.

Example 2

A method for environmental protection and recycling of precious metals in waste circuit boards by joint smelting of waste circuit boards, copper concentrate and desulfurization gypsum, comprising the following steps:

(1) Preparation of waste circuit boards: disassemble the waste circuit boards, remove impurities such as tin, iron, aluminum, copper wires, etc., and then crush them into 20mm copper-containing waste circuit boards by a crusher;

(2) Mixed granulation: Add copper-containing waste circuit boards together with copper concentrate, desulfurization gypsum, and copper concentrate auxiliary materials into the granulator to make 5mm-sized granules. The copper-containing waste circuit boards: copper concentrate The mass ratio of ore: desulfurization gypsum: copper concentrate auxiliary material is 5:150:10:30;

(3) Oxygen furnace smelting: put the above-prepared pellets into Osmelt furnace for smelting. During the smelting process, the air volume of the lance is controlled at 15000Nm ³ /h and the oxygen flow rate is 25000Nm ³ /h through the ultra-oxygen-enriched lance. , keep the temperature of the molten pool in the smelting furnace at 1180~1250 °C, and continue to introduce 5000Nm ³ /h of air into the furnace through the secondary tuyere on the secondary combustion chamber of the flue gas, so that the flue gas is in the flue gas two. The residence time in the secondary combustion chamber is prolonged by 4~5 seconds, the temperature of the flue gas in the furnace reaches 1100~1250℃, and the organic dioxin content in the flue gas is 0.01~0.02 ng TEQ/m ³ ; The flue is concentrated and transported to the waste heat boiler for waste heat recovery;

(4) Valuable metal recovery: after the melt produced by the smelting furnace flows out through the liquid outlet at the lower part of the furnace body, electric furnace sedimentation, converter smelting, refining furnace refining and extraction of copper and copper anode slime are successively carried out to recover gold, silver, platinum and palladium;

(5) Recovery of smelting flue gas: the flue gas after waste heat recovery is dedusted by the flue gas purification device, and then enters the concentrated sulfuric acid absorption tower to produce sulfuric acid. After acid production, the exhaust gas enters the exhaust absorption tower for absorption, and the detected dioxin content is 0.011~ 0.023 ng TEQ/m ³ , which meets the emission standard and is directly evacuated (Recycling Non-ferrous Metal Industry Pollutant Emission Standard (Draft for Comment)) The emission limit of dioxin-like air pollutants for existing enterprises is 1.0 ng·TEQ/ m ³ , the emission limit of air pollutants dioxins in newly built enterprises is 0.5 ng·TEQ/m ³ . After adding sewage acid desulfurization gypsum, the emission concentration of dioxins is less than the limit of 0.5 ng·TEQ/m ³ . The present invention The dioxin in the exhaust gas is far lower than this limit); the sulfuric acid obtained by absorption contains more heavy metal ions, which is added to the sewage acid impurity removal tank, and quicklime is added for impurity removal, filtering, and the obtained filtrate enters the sulfuric acid refining and removal process. Concentrated sulfuric acid is prepared by a hybrid system, and the main component of the obtained filter residue is desulfurized gypsum, which is added to a desulfurized gypsum dryer to dry to a moisture content of ≤15%, and then added to step (2) for recycling, granulation, and recovery of valuable metals.

The copper content in the copper-containing waste circuit board described in the present invention is 30%. The copper concentrate described in the present invention includes mixed low-sulfur ore and mixed high-sulfur ore, wherein the copper content of the mixed low-sulfur ore is 18%, the copper content of the mixed high-sulfur ore is 30%, and the mixed low-sulfur ore is in copper The proportion in the concentrate is 40%.

The copper concentrate auxiliary material in the present invention is composed of coal, quartz stone and limestone.

Example 3

A method for environmental protection and recycling of precious metals in waste circuit boards by joint smelting of waste circuit boards, copper concentrate and desulfurization gypsum, comprising the following steps:

(1) Preparation of waste circuit boards: disassemble the waste circuit boards, remove impurities such as tin, iron, aluminum, copper wire, etc., and crush them into copper-containing waste circuit boards with a size of 30mm by a waste circuit board crusher;

(2) Mixed granulation: Add copper-containing waste circuit boards together with copper concentrate, desulfurization gypsum, and copper concentrate auxiliary materials into the granulator to make 15mm-sized granules. The copper-containing waste circuit boards: copper concentrate The mass ratio of ore: desulfurization gypsum: copper concentrate auxiliary material is 10:180:15:20;

(3) Oxygen furnace smelting: put the above-prepared pellets into Osmelt furnace for smelting. During the smelting process, the air volume of the lance is controlled at 18000Nm ³ /h and the oxygen flow rate is 35000Nm ³ /h through the ultra-oxygen-enriched lance. , keep the temperature of the molten pool in the smelting furnace at 1260~1310 ℃, and continuously introduce 5000Nm ³ /h of air into the furnace through the secondary tuyere on the secondary combustion chamber of the flue gas, so that the flue gas is in the flue gas two The residence time in the secondary combustion chamber is prolonged by 4~5 seconds, the temperature of the flue gas in the furnace reaches 1220~1310℃, and the organic dioxin content in the flue gas is 0.03~0.04 ng TEQ/m ³ ; The flue is concentrated and transported to the waste heat boiler for waste heat recovery;

(4) Valuable metal recovery: after the melt produced by the smelting furnace flows out through the liquid outlet at the lower part of the furnace body, electric furnace sedimentation, converter smelting, refining furnace refining and extraction of copper and copper anode slime are successively carried out to recover gold, silver, platinum and palladium;

(5) Recovery of smelting flue gas: the flue gas after waste heat recovery is dedusted by the flue gas purification device, and then enters the concentrated sulfuric acid absorption tower to produce sulfuric acid. After acid production, the exhaust gas enters the exhaust absorption tower for absorption, and the detected dioxin content is 0.011~ 0.023 ng TEQ/m ³ , which meets the discharge standard, and is directly evacuated; the sulfuric acid obtained by absorption contains many heavy metal ions, which is added to the sewage acid impurity removal tank, and quicklime is added for impurity removal and filtration, and the obtained filtrate is purified by sulfuric acid. The impurity removal system prepares concentrated sulfuric acid, and the main component in the obtained filter residue is desulfurized gypsum, which is added to the desulfurized gypsum dryer and dried to a moisture content of ≤15%, and then added to step (2) for recycling, granulation and recovery of valuable metals .

The copper content in the copper-containing waste circuit board described in the present invention is 20%. Of course, it is also possible for waste circuit boards with higher copper content to be used in the method of the present invention, and the smelting effect will be better.

The copper concentrate described in the present invention includes mixed low-sulfur ores and mixed high-sulfur ores, wherein the copper content of the mixed low-sulfur ores is 25%, the copper content of the mixed high-sulfur ores is 20%, and the mixed low-sulfur ores in copper The proportion in the concentrate is 45%.

The copper concentrate auxiliary material in the present invention is composed of coke, slag concentrate, quartz stone and limestone.

Example 4

A method for environmental protection and recycling of precious metals in waste circuit boards by joint smelting of waste circuit boards, copper concentrate and desulfurization gypsum, comprising the following steps:

(1) Preparation of waste circuit boards: disassemble the waste circuit boards, remove impurities such as tin, iron, aluminum, copper wires, etc., and crush them into 50mm copper-containing waste circuit boards by a crusher;

(2) Mixed granulation: add copper-containing waste circuit boards together with copper concentrate, desulfurization gypsum, and copper concentrate auxiliary materials into the granulator to make 25mm granules. The copper-containing waste circuit boards: copper concentrate The mass ratio of ore: desulfurization gypsum: copper concentrate auxiliary material is 7:170:14:28;

(3) Oxygen furnace smelting: put the above-prepared pellets into Osmelt furnace for smelting. During the smelting process, the air volume of the lance is controlled at 16000Nm ³ /h and the oxygen flow rate is 32000Nm ³ /h through the ultra-oxygen-enriched lance. , keep the temperature of the molten pool in the smelting furnace at 1230~1300 ℃, and continue to introduce 4000Nm ³ /h of air into the furnace through the secondary tuyere on the secondary combustion chamber of the flue gas, so that the flue gas is in the flue gas two The residence time in the secondary combustion chamber is prolonged by 3 to 5 seconds, the temperature of the flue gas in the furnace reaches 1160 to 1300 ° C, and the organic dioxin content in the flue gas is 0.02 to 0.035ng TEQ/m ³ ; The flue is concentrated and transported to the waste heat boiler for waste heat recovery;

(4) Valuable metal recovery: after the melt produced by the smelting furnace flows out through the liquid outlet at the lower part of the furnace body, electric furnace sedimentation, converter smelting, refining furnace refining and extraction of copper and copper anode slime are successively carried out to recover gold, silver, platinum and palladium;

(5) Recovery of smelting flue gas: the flue gas after waste heat recovery is dedusted by the flue gas purification device, and then enters the concentrated sulfuric acid absorption tower to produce sulfuric acid. After acid production, the exhaust gas enters the exhaust absorption tower for absorption, and the detected dioxin content is 0.011~ 0.023 ng TEQ/m ³ , which meets the discharge standard, and is directly evacuated; the sulfuric acid obtained by absorption contains many heavy metal ions, which is added to the sewage acid impurity removal tank, and quicklime is added for impurity removal and filtration, and the obtained filtrate is purified by sulfuric acid. The impurity removal system prepares concentrated sulfuric acid, and the main component in the obtained filter residue is desulfurized gypsum, which is added to the desulfurized gypsum dryer and dried to a moisture content of ≤15%, and then added to step (2) for recycling, granulation and recovery of valuable metals .

The structure of the ultra-oxygen-enriched spray gun used in the step (3) of the present invention has been disclosed in the inventor's prior patent CN111206157A, and its structure is made of four concentric steel cylinders, which extend from the inside to the The pulverized coal, oxygen, lance air and sleeve air are fed in sequence, and the air inlets for oxygen, lance air and sleeve air are opened on the side walls of the concentric steel cylinder in turn.

The copper content in the copper-containing waste circuit board described in the present invention is 22%. Of course, it is also possible for waste circuit boards with higher copper content to be used in the method of the present invention, and the smelting effect will be better.

The copper concentrate described in the present invention includes mixed low-sulfur ores and mixed high-sulfur ores, wherein the copper content of the mixed low-sulfur ores is 23%, and the copper content of the mixed high-sulfur ores is 28%. The proportion in the concentrate is 48%.

The copper concentrate auxiliary material in the present invention is composed of coke, quartz stone and limestone.

Example 5

Referring to Figure 1, the technical solution of the present invention is: a device for combined smelting of waste circuit boards and copper concentrate to recover precious metals in waste circuit boards, including a waste circuit board crusher 2, especially: the waste circuit board crusher is provided with Belt conveyor 1, a disc granulator 3 is arranged behind the waste circuit board crusher, and there are four feeding hoppers above the disc granulator, which are copper concentrate feeding hopper 4, waste circuit board feeding hopper 5, copper Concentrate auxiliary material feeding hopper 6 and desulfurization gypsum feeding hopper 7; after the above four kinds of raw materials are granulated by the disc granulator 3, they are sent to the Osmelt furnace 8 by the belt conveyor 1 for smelting, and the smelted charge is released Go to the copper refining furnace to refine and produce copper and recover other rare and precious metals (not shown in the figure); after the Osmelt furnace 8, a waste heat recovery boiler 9, a flue gas purification chamber 10, a sulfuric acid absorption tower 11, a sewage The acid removal tank 12, the dirty acid filter 13 and the desulfurization gypsum dryer 14, the flue gas generated by the Osmelt furnace smelting 8 is recovered by the waste heat recovery boiler 9, and then enters the flue gas purification chamber 10 for purification, and then enters the The sulfuric acid absorption tower 11 absorbs sulfur dioxide and sulfur trioxide to produce sulfuric acid, and the polluted acid after absorbing the flue gas is put into the polluted acid impurity removal tank 12, after adding quicklime for impurity removal, it is put into the polluted acid filter 13 for filtration, resulting in The filtered residue is put into the desulfurized gypsum dryer 14 for drying, and then it can be returned to the desulfurized gypsum hopper 7 above the disc granulator 3 for circulating batching. A pump 16 and a valve 17 are required.

In this embodiment, the sulfuric acid absorption tower 11 is also connected with a tail gas absorption tower 18 for absorbing untreated sulfur dioxide tail gas.

In this embodiment, a dust collecting device 19 is further provided above the waste circuit board crusher 2 for collecting and centrally processing the dust generated by the crusher.

The above-mentioned embodiments are only exemplary to interpret the claims of the present invention, and do not limit the present invention in any form. Anyone who makes equivalent changes, enlarges or reduces the scope according to the principles of the claims of the present invention should be regarded as falling within the scope of the present invention. into the scope of protection of the claims of the present invention.

Claims (7)

1. The method for recovering noble metals in waste circuit boards in an environment-friendly manner by jointly smelting the waste circuit boards, copper concentrate and desulfurized gypsum is characterized by comprising the following steps:

(1) preparing a waste circuit board: disassembling the waste circuit board, removing impurities such as tin, iron, aluminum, copper wires and the like, and crushing the waste circuit board into a copper-containing waste circuit board with the size of 20-50 mm by a crusher;

(2) mixing and granulating: adding the copper-containing waste circuit board, copper concentrate, desulfurized gypsum and copper concentrate auxiliary materials into a granulator to prepare granules with the size of 5-25 mm, wherein the copper-containing waste circuit board comprises the following components in parts by weight: copper concentrate: desulfurized gypsum: the mass ratio of the copper concentrate auxiliary materials is 5-10: 150-180: 10-15: 20-30;

(3) carrying out ore furnace smelting: putting the prepared granular material into an Osmant furnace for smelting, and controlling the air volume of a spray gun to be 15000-18000 Nm through an ultra-oxygen-enriched spray gun in the smelting process³The flow rate of oxygen is 25000-35000 Nm³The temperature of a molten pool in the smelting furnace is kept at 1180-1310 ℃, and 1000-5000 Nm is continuously introduced into the furnace through a secondary air port on a flue gas secondary combustion chamber³The residence time of the flue gas in the flue gas secondary combustion chamber is prolonged by 1-5 seconds through the air per hour, the temperature of the flue gas in the furnace reaches 1100-1310 ℃, and the content of organic matter dioxin in the flue gas is 0.01-0.04 ng TEQ/m³(ii) a High-temperature flue gas generated by the smelting furnace is concentrated by a flue and then is conveyed to a waste heat boiler for waste heat recovery;

(4) recovering valuable metals: after a melt generated by the smelting furnace flows out from a liquid outlet at the lower part of the furnace body, electric furnace sedimentation, converter smelting and refining in a refining furnace are sequentially carried out to extract copper and copper anode mud to recover gold, silver, platinum and palladium;

(5) smelting flue gas recovery: flue gas after waste heat recovery is dedusted by a flue gas purification device, the flue gas enters a concentrated sulfuric acid absorption tower to produce sulfuric acid, and tail gas after acid preparation enters a tail gas absorption tower to be absorbed, so that the detected dioxin content is 0.011-0.023 ng TEQ/m³Directly carrying out evacuation treatment when the wastewater reaches the discharge standard; absorbing to obtain sulfuric acid containing more heavy metal ions, adding into a contaminated acid impurity removal tank, adding quicklime for impurity removal, filtering, making concentrated sulfuric acid from the filtrate in a sulfuric acid refining impurity removal system, adding desulfurized gypsum as main component in the obtained filter residue, and drying in a desulfurized gypsum dryer until the water content is less than or equal to 15%And (3) adding the mixture into the step (2) for recycling, granulating and recovering valuable metals.

2. The method for environment-friendly recovery of precious metals in waste circuit boards by combined smelting of waste circuit boards, copper concentrate and desulfurized gypsum according to claim 1, wherein the method comprises the following steps: the copper content in the waste circuit board containing copper is 10-30%.

3. The method for environment-friendly recovery of precious metals in waste circuit boards by combined smelting of waste circuit boards, copper concentrate and desulfurized gypsum according to claim 1, wherein the method comprises the following steps: the copper concentrate comprises mixed low-sulfur ores and mixed high-sulfur ores, wherein the copper content of the mixed low-sulfur ores is 18-25%, the copper content of the mixed high-sulfur ores is 20-30%, and the proportion of the mixed low-sulfur ores in the copper concentrate is not more than 50%.

4. The method for environment-friendly recovery of precious metals in waste circuit boards by combined smelting of waste circuit boards, copper concentrate and desulfurized gypsum according to claim 1, wherein the method comprises the following steps: the copper concentrate auxiliary material is composed of one or more of coke, slag concentrate, smoke dust, quartz, limestone and coal.

5. The apparatus for the method of the waste circuit board, the copper concentrate and the desulfurized gypsum combined smelting environment-friendly recovery of the noble metals in the waste circuit board according to claim 1, which comprises a waste circuit board crusher, and is characterized in that: a belt conveyor is arranged in front of the waste circuit board crusher, a disc granulator is arranged behind the waste circuit board crusher, and four charging hoppers, namely a copper concentrate charging hopper, a waste circuit board charging hopper, a copper concentrate auxiliary material charging hopper and a desulfurized gypsum charging hopper, are arranged above the disc granulator; after the four raw materials are granulated by a disc granulator, the four raw materials are conveyed to an Osmant furnace by a belt conveyor for smelting, and the smelted furnace burden is discharged to a copper refining furnace for refining to produce copper and recovering other rare and precious metals; the waste heat recovery boiler, the flue gas clean room, the sulfuric acid absorption tower, the dirty sour edulcoration jar, dirty sour filter and desulfurized gypsum drying-machine are equipped with in proper order behind the oeomatt furnace, flue gas that the oeomatt furnace was smelted and is produced is after waste heat recovery boiler retrieves the waste heat, get into the flue gas clean room and purify, reentrant sulfur dioxide in the sulfuric acid absorption tower, sulfur trioxide production sulfuric acid, the dirty acid that has absorbed the flue gas is put into dirty sour edulcoration jar, add quick lime and carry out the edulcoration back, put into dirty sour filter and filter, the filter residue that produces is put into desulfurized gypsum drying-machine and is dried, can return in the desulfurized gypsum loading hopper of disc granulator top, be used for the circulation batching, all be equipped with pump and valve as required on the connecting tube between the above-mentioned each device.

6. The device for recovering the noble metals in the waste circuit boards by the joint smelting of the waste circuit boards and the copper concentrates as claimed in claim 5, is characterized in that: and a tail gas absorption tower is connected behind the sulfuric acid absorption tower and is used for absorbing untreated sulfur dioxide tail gas.

7. The device for recovering the noble metals in the waste circuit boards by the joint smelting of the waste circuit boards and the copper concentrates as claimed in claim 5, is characterized in that: and a dust collecting device is also arranged above the waste circuit board crusher and used for collecting and centrally treating dust generated by the crusher.

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