Method for recovering tin in copper dross

Abstract

The invention discloses a method for recovering tin in copper dross, and belongs to the metal smelting industry. The method comprises the following steps: continuously adding raw material copper dross into a smelting furnace provided with a spray gun, and performing low-temperature smelting in a micro-oxidizing atmosphere; after low-temperature smelting, crude lead, tin-rich high-lead slag, matte and flue gas are produced; most of lead metal in the copper dross enters crude lead, and a small part of the lead metal enters high-lead dross; tin is oxidized and enters high-lead slag, and copper enters matte; the produced matte is further blown into crude copper, flue gas is subjected to dust collection, smoke dust is returned for treatment, the flue gas is discharged after reaching the standard after being treated, and crude lead is further refined; the produced tin-rich high-lead slag is transferred into another smelting furnace to be subjected to a reduction reaction, and tin-lead alloy is produced; and recovering lead and tin from the produced tin-lead alloy by adopting a vacuum distillation method to obtain crude lead and crude tin. The method for recovering the tin in the copper dross has the advantages of convenience in operation, low investment, high recovery rate, low energy consumption, low cost and the like; the tin recovery rate reaches 90% or above.

Description

1. Technical field:

[0001] The invention belongs to the metal smelting industry, and in particular relates to a method for recovering tin from copper slag. 2. Background technology:

[0002] Copper slag is a product composed of impurity compounds and mechanically entrained main metal droplets formed during the process of pyrometallurgical refining and copper removal of crude lead. Due to different slag removal methods or slag removal equipment, the morphology and composition of copper slag vary greatly. Generally, the main components are lead and copper, in addition to tin, arsenic, antimony, bismuth, zinc and other elements. The main phases of copper slag are lead sulfide, lead oxide, lead, copper sulfide, copper-arsenic alloy, copper-tin alloy and lead-tin alloy. Copper slag is an important secondary resource in the lead smelting process. If it is not recycled, it will not only cause a waste of metal resources, but also the heavy metals in it will pose a serious threat to the environment and human health.

[0003] Most manufacturers do not recycle copper slag, but some manufacturers do. There are two main recycling methods: wet process and pyrometallurgical process. The wet process uses leaching to make tin enter the leaching solution, and then uses sulfide precipitation or other methods for recovery.

[0004] At present, the commonly used method for copper slag recovery is pyrometallurgical treatment, and there are also related patent documents reporting the pyrometallurgical recovery of copper slag. For example: Invention patent application CN202210108883.2 discloses a method for smelting copper slag to recover valuable metals, which uses copper slag, iron filings, slag-making agent and reducing agent as raw materials for batching; the prepared materials are added to the smelting furnace for heating reduction smelting, and after reduction smelting, crude lead, smelting slag, matte and flue gas are produced; the lead metal in the copper slag enters the crude lead, the tin metal enters the crude lead, and the copper metal enters the matte; the crude lead produced enters the tin removal process, and after making tin slag, it enters the crude lead electrolysis process to produce electrolytic lead; the matte is transferred to the copper smelting system for recycling; the flue gas is treated by dust collection, and the flue gas obtained after treatment enters the exhaust system for emptying, and the obtained ash returns to the smelting process as a batching for reuse.

[0005] In the existing wet process for treating copper slag, in order to ensure the leaching effect, the raw materials need to be crushed and ground into powder. During the crushing and grinding process, the power consumption is large. At the same time, due to the low tin content of the raw materials, the production cost is high, and the cost of treating wastewater is also required; the invention patent application CN202210108883.2 for recovering copper slag by pyrometallurgical process discloses a method for smelting copper slag to recover valuable metals. Although this method can recover tin, due to the slag-making agent replacing soda ash for slag-making in the reduction smelting process , part of the tin reacts with the Na2O of the slag-making agent and enters the slag, resulting in a low tin recovery rate; at the same time, due to the high lead content in the copper slag, the amount of crude lead produced is large, and the tin content in the crude lead is ≤1%, which brings certain difficulties to the next step of recovery and affects the next step of tin recovery rate; during reduction smelting, the smelting temperature is 1150-1250°C, the smelting temperature is relatively high, the cost is high, and the energy consumption is high; the smelting time is 12 hours per furnace, the operation is intermittent, and the degree of automation is low; iron filings, slag-making agents and reducing agents are added during the batching, which is costly. 3. Summary of the invention:

[0006] The technical problem to be solved by the present invention is: in view of the problems of high smelting temperature, high cost, high energy consumption and intermittent operation in the existing production technology for recovering tin from copper slag, the present invention provides a method for recovering tin from copper slag. The method for recovering tin from copper slag of the present invention has the advantages of convenient operation, low investment, high recovery rate, low energy consumption and low cost.

[0007] In order to solve the above problems, the technical solution adopted by the present invention is:

[0008] The present invention provides a method for recovering tin in copper slag, and the recovery method comprises the following steps:

[0009] 1) The raw copper slag is continuously added into a smelting furnace equipped with a spray gun, oxygen and natural gas are introduced through the spray gun, and a low-temperature smelting reaction is performed in a slightly oxidizing atmosphere; during the smelting reaction, the smelting temperature is controlled to be 700-850°C;

[0010] 2) After low-temperature smelting reaction, crude lead, tin-rich high-lead slag, matte and flue gas are produced; most of the lead metal in the copper slag enters the crude lead, and a small part enters the high-lead slag; tin oxidation enters the high-lead slag, and copper enters the matte; the produced matte is further refined into crude copper, and the flue gas is returned for treatment after dust collection. The flue gas is discharged after being treated to meet the standards, and the crude lead is further refined;

[0011] 3) The produced tin-rich and high-lead slag is transferred to another smelting furnace for reduction reaction to produce tin-lead alloy;

[0012] 4) The produced tin-lead alloy is subjected to vacuum distillation to recover lead and tin to obtain crude lead and crude tin.

[0013] According to the above method for recovering tin from copper slag, in step 1), the lead content in the copper slag is 60-80%, the copper content is 5-20%, the arsenic content is 3-8%, and the tin content is 0.3-1.0%.

[0014] According to the above-mentioned method for recovering tin from copper dross, the smelting furnace in step 1) is a bottom-blowing smelting furnace or a side-blowing smelting furnace provided with a spray gun.

[0015] According to the above-mentioned method for recovering tin from copper slag, in step 1), the amount of oxygen introduced into the slightly oxidizing atmosphere is 20-30 Nm / ton of copper slag. 3 / h; the oxygen input for heating per ton of copper slag is 15-20Nm 3 / h, the oxygen flow rate used to maintain the slightly oxidizing atmosphere is 5-10Nm 3 / h; the amount of natural gas introduced per ton of copper slag is 8-10Nm 3 / h.

[0016] According to the above-mentioned method for recovering tin from copper slag, the crude lead produced in step 2) has a lead content of 94-98%, an arsenic content of 1-6%, and a tin content of less than 0.001%; ​​the tin content of the produced tin-rich and high-lead slag is 2-15%; the copper content of the produced matte is 40-60%, the lead content is 15-25%, and the arsenic content is less than 1%.

[0017] According to the above-mentioned method for recovering tin from copper slag, the reducing agent added in the reduction reaction process of step 3) is pyrite or iron powder; the amount of the reducing agent used is 0.2-0.5 ton of reducing agent / ton of copper slag.

[0018] According to the above-mentioned method for recovering tin from copper slag, during the reduction reaction in step 3), the reduction reaction temperature is controlled to be 1100-1250° C. and the time is 6-8 hours (including a heating stage of 2 hours and a reduction reaction stage of 4-6 hours).

[0019] According to the above method for recovering tin from copper slag, the tin content of the tin-lead alloy produced in step 3) is 7-13% and the lead content is 70-80%.

[0020] According to the above method for recovering tin from copper slag, the temperature during vacuum distillation in step 4) is controlled to be 1000-1100°C.

[0021] According to the above-mentioned method for recovering tin from copper slag, the lead content in the crude lead obtained in step 4) is ≥97%, and the tin content in the crude tin obtained is 80-85%.

[0022] The positive beneficial effects of the present invention are:

[0023] 1. When recovering tin from copper slag, the present invention adopts low-temperature smelting, and the smelting temperature is 700-850°C; it is more than 300°C lower than the conventional smelting temperature, thereby saving energy, saving costs, reducing energy consumption, and having significant economic benefits.

[0024] 2. The technical solution of the present invention adopts low-temperature smelting in a micro-oxidizing atmosphere to oxidize and enrich tin in the slag to form high-tin-grade tin-rich and high-lead slag. The tin enrichment rate reaches 99%, thereby improving the tin recovery rate, which is as high as more than 90%.

[0025] 3. The technical solution of the present invention adopts a smelting furnace with a spray gun to enable the material to quickly transfer heat and mass, thereby accelerating the reaction and saving energy.

[0026] 4. The technical solution of the present invention utilizes the properties of copper slag and directly melts it at low temperature, so that the elemental lead in the copper slag is directly melted into crude lead, and the lead oxide forms slag without adding other auxiliary materials. The slag amount is small and the slag contains high tin, which saves costs and improves the recovery rate of tin (the recovery rate of tin is as high as more than 90%).

[0027] 5. The technical solution of the present invention has quantitative and continuous material feeding, stable production, good environmental protection conditions and high degree of automation.

[0028] 6. The present invention adopts pyrometallurgical equipment for treatment, and no waste water is generated, which is beneficial to environmental protection.

[0029] In summary, the present invention has significant economic and social benefits. 4. Specific implementation methods:

[0030] The present invention is further described below in conjunction with embodiments, but the protection scope of the technical solution of the present invention is not limited thereto.

[0031] Embodiment 1:

[0032] The method for recovering tin from copper slag of the present invention comprises the following detailed steps:

[0033] 1) The raw copper slag is continuously added into a bottom-blown smelting furnace equipped with a spray gun at a rate of 8 t / h. Natural gas and oxygen are introduced into the spray gun. The amount of natural gas introduced is 80 Nm 3 / h, oxygen flow rate is 200Nm 3 / h, and conduct low-temperature smelting reaction in a slightly oxidizing atmosphere, and control the smelting temperature to be 750-800°C during the smelting reaction;

[0034] The raw copper slag used contains 72% lead, 12% copper, 5% arsenic and 0.5% tin;

[0035] 2) After low-temperature smelting reaction, crude lead (containing 97% lead, 2% arsenic, and 0.0006% tin), tin-rich high-lead slag (containing 40% lead and 5% tin in the tin-rich high-lead slag), matte (containing 40% copper, 20% lead, and 0.6% arsenic in the matte) and flue gas are produced; most of the lead metal in the copper slag enters the crude lead, and a small part enters the high-lead slag; tin oxidation enters the high-lead slag, and copper enters the matte; the produced matte is further refined into crude copper, and the flue gas is returned for treatment after dust collection. The flue gas is discharged after being treated to meet the standards, and the crude lead is further refined;

[0036] 3) The produced tin-rich and high-lead slag is transferred to another bottom-blown smelting furnace, and pyrite is added for reduction reaction to produce a tin-lead alloy; during the reduction reaction, the amount of pyrite added is 3 tons / h, the temperature is controlled at 1100-1150°C, and the time is 6 hours (2 hours for the heating stage and 4 hours for the reduction reaction stage); the obtained tin-lead alloy contains 11% tin and 76% lead;

[0037] 4) The produced tin-lead alloy is subjected to vacuum distillation at 1000-1050° C. to recover lead and tin, thereby producing crude lead and crude tin (the lead content in the crude lead is 98%; the tin content in the crude tin is 84%).

[0038] In this embodiment, tin in copper slag is recovered, and the tin recovery rate is 92%.

[0039] Embodiment 2:

[0040] The method for recovering tin from copper slag of the present invention comprises the following detailed steps:

[0041] 1) The raw copper slag is continuously added into a bottom-blown smelting furnace equipped with a spray gun at a rate of 10 t / h. Natural gas and oxygen are introduced into the spray gun. The natural gas introduction rate is 95 Nm 3 / h, oxygen flow rate is 250Nm 3 / h, and conduct low-temperature smelting reaction in a slightly oxidizing atmosphere, and control the smelting temperature to be 800-850°C during the smelting reaction;

[0042] The raw copper slag used contains 65% lead, 17% copper, 8% arsenic and 0.8% tin;

[0043] 2) After low-temperature smelting reaction, crude lead (containing 96% lead, 6% arsenic, and 0.0007% tin), tin-rich high-lead slag (containing 40% lead and 8% tin in the tin-rich high-lead slag), matte (containing 40% copper, 16% lead, and 0.9% arsenic in the matte) and flue gas are produced; most of the lead metal in the copper slag enters the crude lead, and a small part enters the high-lead slag; tin oxidation enters the high-lead slag, and copper enters the matte; the produced matte is further refined into crude copper, and the flue gas is returned for treatment after dust collection. The flue gas is discharged after being treated to meet the standards, and the crude lead is further refined;

[0044] 3) The produced tin-rich and high-lead slag is crushed and transferred to another bottom-blown smelting furnace, and pyrite is added for reduction reaction to produce tin-lead alloy; during the reduction reaction, the amount of pyrite added is 3 tons / h, the temperature is controlled at 1150-1200°C, and the time is 6 hours (2 hours for the heating stage and 4 hours for the reduction reaction stage); the obtained tin-lead alloy contains 13% tin and 74% lead;

[0045] 4) The produced tin-lead alloy is subjected to vacuum distillation at 1050-1100° C. to recover lead and tin, thereby producing crude lead and crude tin (the lead content in the crude lead is 97%; the tin content in the crude tin is 84%).

[0046] This embodiment recovers tin from copper slag, and the tin recovery rate is 94%.

[0047] Embodiment 3:

[0048] The method for recovering tin from copper slag of the present invention comprises the following detailed steps:

[0049] 1) The raw copper slag is continuously added into a bottom-blown smelting furnace equipped with a spray gun at a rate of 10 t / h. Natural gas and oxygen are introduced into the spray gun. The amount of natural gas introduced is 80 Nm 3 / h, oxygen flow rate is 280Nm 3 / h, and conduct low-temperature smelting reaction in a slightly oxidizing atmosphere, and control the smelting temperature to be 780-820°C during the smelting reaction;

[0050] The raw copper slag used contains 78% lead, 7% copper, 4% arsenic and 0.3% tin;

[0051] 2) After low-temperature smelting reaction, crude lead (containing 98% lead, 1% arsenic, and 0.0004% tin), tin-rich high-lead slag (containing 40% lead and 3% tin in the tin-rich high-lead slag), matte (containing 40% copper, 24% lead, and 0.3% arsenic in the matte) and flue gas are produced; most of the lead metal in the copper slag enters the crude lead, and a small part enters the high-lead slag; tin oxidation enters the high-lead slag, and copper enters the matte; the produced matte is further refined into crude copper, and the flue gas is returned for treatment after dust collection. The flue gas is discharged after being treated to meet the standards, and the crude lead is further refined;

[0052] 3) The produced tin-rich and high-lead slag is transferred to another bottom-blown smelting furnace, and pyrite is added for reduction reaction to produce a tin-lead alloy; during the reduction reaction, the amount of pyrite added is 2 tons / h, the temperature is controlled at 1200-1250°C, and the time is 6 hours (2 hours for the heating stage and 4 hours for the reduction reaction stage); the obtained tin-lead alloy contains 9% tin and 80% lead;

[0053] 4) The produced tin-lead alloy is subjected to vacuum distillation at 1000-1050° C. to recover lead and tin, thereby producing crude lead and crude tin (the lead content in the crude lead is 98%; the tin content in the crude tin is 83%).

[0054] In this embodiment, tin in copper slag is recovered, and the tin recovery rate is 91%.

Claims

1. A method for recovering tin from copper slag, characterized in that: The recovery method comprises the following steps: 1) The raw copper slag is continuously added into a smelting furnace equipped with a spray gun, oxygen and natural gas are introduced through the spray gun, and a low-temperature smelting reaction is performed in a slightly oxidizing atmosphere; during the smelting reaction, the smelting temperature is controlled to be 700-850°C; 2) After low-temperature smelting reaction, crude lead, tin-rich high-lead slag, matte and flue gas are produced; most of the lead metal in the copper slag enters the crude lead, and a small part enters the high-lead slag; tin oxidation enters the high-lead slag, and copper enters the matte; the produced matte is further refined into crude copper, and the flue gas is returned for treatment after dust collection. The flue gas is discharged after being treated to meet the standards, and the crude lead is further refined; 3) The produced tin-rich and high-lead slag is transferred to another smelting furnace for reduction reaction to produce tin-lead alloy; 4) The produced tin-lead alloy is subjected to vacuum distillation to recover lead and tin to obtain crude lead and crude tin.

2. The method for recovering tin from copper slag according to claim 1, characterized in that: Step 1) The copper slag contains 60-80% lead, 5-20% copper, 3-8% arsenic and 0.3-1.0% tin.

3. The method for recovering tin from copper slag according to claim 1, characterized in that: The smelting furnace in step 1) is a bottom-blowing smelting furnace or a side-blowing smelting furnace equipped with a lance.

4. The method for recovering tin from copper slag according to claim 1, characterized in that: Step 1) In the slightly oxidizing atmosphere, the amount of oxygen introduced per ton of copper slag is 20-30 Nm 3 / h; the oxygen input for heating per ton of copper slag is 15-20Nm 3 / h, the oxygen flow rate used to maintain the slightly oxidizing atmosphere is 5-10Nm 3 / h; the amount of natural gas introduced per ton of copper slag is 8-10Nm 3 / h.

5. The method for recovering tin from copper slag according to claim 1, characterized in that: The crude lead produced in step 2) has a lead content of 94-98%, an arsenic content of 1-6%, and a tin content of less than 0.001%; ​​the tin content of the tin-rich high-lead slag produced is 2-15%; the copper content of the matte produced is 40-60%, the lead content is 15-25%, and the arsenic content is less than 1%.

6. The method for recovering tin from copper slag according to claim 1, characterized in that: In step 3), the reducing agent added during the reduction reaction is pyrite or iron powder; the amount of the reducing agent used is 0.2 to 0.5 ton of reducing agent per ton of copper slag.

7. The method for recovering tin from copper slag according to claim 1, characterized in that: Step 3) During the reduction reaction, the reduction reaction temperature is controlled to be 1100-1250° C. and the time is 6-8 hours.

8. The method for recovering tin from copper slag according to claim 1, characterized in that: Step 3) The tin-lead alloy produced has a tin content of 7-13% and a lead content of 70-80%.

9. The method for recovering tin from copper slag according to claim 1, characterized in that: Step 4) The temperature during vacuum distillation is controlled at 1000-1100°C.

10. The method for recovering tin from copper slag according to claim 1, characterized in that: Step 4) The lead content in the obtained crude lead is ≥97%, and the tin content in the obtained crude tin is 80-85%.