Refining impurity cleaning and removing process for secondary copper

Abstract

The invention discloses a refining impurity cleaning and removing process for secondary copper, which comprises the following steps: (a) pretreatment melting: melting a secondary copper raw material to form copper liquid, and controlling the temperature to be 1150-1250 DEG C; (b) oxidizing and slagging: introducing oxygen-containing gas into the copper liquid for 20-40 minutes to oxidize impurity elements to form scum; according to the refining impurity cleaning and removing process for the secondary copper, As and Sn are converted into high-valence oxides through oxidation, then a low-melting-point borate slag system is formed through borax in the composite flux, and efficient trapping of impurities is achieved. The mass transfer process is enhanced, flux agglomeration is avoided, and the impurity removal rate is increased by 30% or above. The borax / calcium fluoride combination significantly reduces the melting point of the slag system (actually measured lt; and the lead and tin removal efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of recycled copper, and in particular to a refining impurity removal process for recycled copper. Background Art

[0002] The continuous expansion of my country's smelting and processing enterprises has led to an increase in demand for raw materials, and the contradiction between supply and demand has become increasingly prominent. Domestic smelting capacity has expanded rapidly, and smelters' demand for raw materials will become increasingly dependent on scrap copper. Recycled copper is a product that is smelted again after recycling scrap copper.

[0003] Due to its complex sources, recycled copper often contains As, Pb, Sn and other difficult-to-remove impurities (content can reach 0.5-5%). Traditional processes have:

[0004] Large flux consumption (3-5%) and high cost

[0005] Long refining cycle (>2 hours)

[0006] High impurity residue (As>0.1%)

[0007] There is an urgent need to develop efficient and low-cost purification processes. Summary of the Invention

[0008] The object of the present invention is to provide a refining impurity removal process for recycled copper, so as to solve the above-mentioned problems of the refining impurity removal process for recycled copper on the market today.

[0009] To achieve the above object, the present invention provides the following technical solution: a refining impurity removal process for recycled copper, comprising the following steps:

[0010] (a) Pretreatment melting: melting the recycled copper raw material to form copper liquid, controlling the temperature at 1150-1250°C;

[0011] (b) Oxidation slagging: oxygen-containing gas is introduced into the copper liquid to oxidize the impurity elements to form slag, and the ventilation time is 20-40 minutes;

[0012] (c) Composite flux refining: Add composite flux, the composition of which is as follows by mass percentage:

[0013] Borax 40-60%

[0014] Sodium carbonate 20-30%

[0015] Calcium fluoride 10-20%

[0016] Silicon dioxide 5-15%;

[0017] (d) Directional stirring: using an electromagnetic stirring device at a speed of 200-500 rpm for 10-30 minutes;

[0018] (e) Layer separation: After standing and layering, remove the scum to obtain refined copper liquid.

[0019] Preferably, the gas introduced in step (b) is a mixture of compressed air and pure oxygen, with an oxygen concentration of 30-50 vol%.

[0020] Preferably, the added amount of the composite flux is 0.5-2.0% of the mass of the copper liquid.

[0021] Preferably, the electromagnetic stirring in step (d) adopts an alternating forward and reverse rotation mode, switching the direction every 5 minutes.

[0022] A system for implementing any of the above processes includes: a smelting furnace, a gas injection device, a flux feeder, an electromagnetic stirrer and a slag-liquid separator.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) Oxidation-flux synergistic mechanism: As and Sn are first oxidized to convert into high-valent oxides, and then a low-melting-point borate slag system is formed through the borax in the composite flux to achieve efficient impurity capture.

[0025] (2) Dynamic electromagnetic stirring: Strengthens the mass transfer process, avoids flux agglomeration, and increases the impurity removal rate by more than 30%.

[0026] (3) Innovative flux formula: The borax / calcium fluoride combination significantly reduces the melting point of the slag system (measured <900°C) and improves the removal efficiency of lead and tin. DETAILED DESCRIPTION

[0027] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0028] Example 1:

[0029] A refining impurity removal process for recycled copper, the production and application of which are described in detail below, comprises the following steps:

[0030] (a) Pretreatment melting: The recycled copper raw material is melted to form a copper liquid, and the temperature is controlled at 1150°C;

[0031] (b) Oxidation slagging: oxygen-containing gas is introduced into the copper liquid to oxidize the impurity elements to form slag, and the ventilation time is 20 minutes;

[0032] (c) Composite flux refining: Add composite flux, the composition of which is as follows by mass percentage:

[0033] Borax 40%

[0034] Sodium carbonate 30%

[0035] Calcium fluoride 20%

[0036] Silicon dioxide 10%;

[0037] (d) Directional stirring: using an electromagnetic stirring device at 200 rpm for 10 min;

[0038] (e) Layer separation: After standing and layering, remove the scum to obtain refined copper liquid.

[0039] Preferably, the gas introduced in step (b) is a mixture of compressed air and pure oxygen, with an oxygen concentration of 30 vol%.

[0040] Preferably, the amount of the composite flux added is 0.5% of the mass of the copper liquid.

[0041] Preferably, the electromagnetic stirring in step (d) adopts an alternating forward and reverse rotation mode, switching the direction every 5 minutes.

[0042] A system for implementing any of the above processes includes: a smelting furnace, a gas injection device, a flux feeder, an electromagnetic stirrer and a slag-liquid separator.

[0043] Example 2:

[0044] A refining impurity removal process for recycled copper, the production and application of which are described in detail below, comprises the following steps:

[0045] (a) Pretreatment melting: melting the recycled copper raw material to form copper liquid, controlling the temperature at 1250°C;

[0046] (b) Oxidation slagging: oxygen-containing gas was introduced into the copper liquid to oxidize the impurity elements to form slag, and the ventilation time was 40 minutes;

[0047] (c) Composite flux refining: Add composite flux, the composition of which is as follows by mass percentage:

[0048] Borax 60%

[0049] Sodium carbonate 20%

[0050] Calcium fluoride 15%

[0051] Silicon dioxide 5%;

[0052] (d) Directional stirring: using an electromagnetic stirring device at 500 rpm for 30 min;

[0053] (e) Layer separation: After standing and layering, remove the scum to obtain refined copper liquid.

[0054] Preferably, the gas introduced in step (b) is a mixture of compressed air and pure oxygen, with an oxygen concentration of 50 vol%.

[0055] Preferably, the added amount of the composite flux is 2.0% of the mass of the copper liquid.

[0056] Preferably, the electromagnetic stirring in step (d) adopts an alternating forward and reverse rotation mode, switching the direction every 5 minutes.

[0057] A system for implementing any of the above processes includes: a smelting furnace, a gas injection device, a flux feeder, an electromagnetic stirrer and a slag-liquid separator.

[0058] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0059] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A process for removing impurities from refining copper, characterized in that: The following steps are involved: (a) Pretreatment melting: The recycled copper raw material is melted to form copper liquid, and the temperature is controlled at 1150-1250°C; (b) Oxidation slagging: oxygen-containing gas is introduced into the copper liquid to oxidize the impurity elements to form slag, and the ventilation time is 20-40 minutes; (c) Composite flux refining: Add composite flux, the composition of which is as follows by mass percentage: Borax 40-60% Sodium carbonate 20-30% Calcium fluoride 10-20% Silicon dioxide 5-15%; (d) Directional stirring: using an electromagnetic stirring device at a speed of 200-500 rpm for 10-30 minutes; (e) Layer separation: After standing and layering, remove the scum to obtain refined copper liquid.

2. A process for removing refining impurities from recycled copper according to claim 1, characterized in that: The gas introduced in step (b) is a mixture of compressed air and pure oxygen, with an oxygen concentration of 30-50 vol%.

3. The process for removing refining impurities from recycled copper according to claim 1, wherein: The added amount of the composite flux is 0.5-2.0% of the mass of the copper liquid.

4. The process for removing refining impurities from recycled copper according to claim 1, wherein: In the step (d), the electromagnetic stirring adopts an alternating forward and reverse rotation mode, and the direction is switched every 5 minutes.

5. A system for implementing any process of claims 1-4, characterized in that: include: Melting furnace, gas injection device, flux feeder, electromagnetic stirrer and slag-liquid separator.