1. The process for recovering valuable metals from smelting waste liquid comprises the following steps: 1) carrying out circulating concentration and primary filter pressing on the acidic wastewater generated by purification and washing in a purification system, reducing emission of primary clear liquid by 80-85%, and recovering waste residues generated by primary filter pressing; 2) adding acid-absorbing resin into the primary clear liquid to absorb acid in the primary clear liquid, adding an oxidant to oxidize bivalent iron in the primary clear liquid into trivalent iron ions to obtain secondary clear liquid and waste acid, adding iron yellow seed crystals to perform a heating reaction, adjusting the pH value to 1.5-4.5, and separating out iron in the waste acid in the form of iron yellow; 3) adding zinc powder into the secondary clear liquid to replace copper in the secondary clear liquid, adding a flocculating agent into the secondary clear liquid for many times in the replacement process, stirring by using a stirring device, adjusting the pH value of the secondary clear liquid after copper precipitation to 6.5-8.0, and precipitating zinc hydroxide to obtain barren liquor; 4) and (3) carrying out filter pressing on the barren solution by a filter press again, adding an alkaline solution into the barren solution subjected to filter pressing for size mixing and neutralization, and discharging after the pH value reaches the standard.

2. The process for recovering valuable metals from metallurgical waste liquid according to claim 1, characterized in that: the alkaline solution in the step 4) is sodium sulfide.

3. The process for recovering valuable metals from metallurgical waste liquid according to claim 2, characterized in that: the volume ratio of the barren solution to the sodium sulfide solution in the step 4) is 60-225:1, so that the removal rate of cadmium elements in the acid wastewater can be ensured to be more than 98%, and the removal rate of iron and zinc elements can be more than 99%.

4. The process for recovering valuable metals from metallurgical waste liquid according to claim 1, characterized in that: the size mixing concentration in the step 4) is 30-50 wt%.

5. The process for recovering valuable metals from metallurgical waste liquid according to claim 1, characterized in that: the components of the acidic wastewater in the step 1) are as follows: 15-30g/L of sodium hydroxide, 1-3g/L of sodium cyanide, 0.01-0.03mg/L of gold, 0.10-0.50mg/L of silver, 3-6g/L of copper and 3-5g/L of zinc.

6. The process for recovering valuable metals from metallurgical waste liquid according to claim 1, characterized in that: the flocculating agent in the step 3) is a mixture of sodium sulfide and aluminum sulfate.

7. The process for recovering valuable metals from metallurgical waste liquid according to claim 1, characterized in that: the acid absorption resin in the step 2) is a tough gel body strong base type anion exchange resin with a polystyrene framework containing quaternary amine II type functional groups.

Background

During the process of producing sulfuric acid and extracting copper sulfate from gold smelting fume, a great deal of pickling waste water is produced, which is approximately 5-8% of sulfuric acid, 1-2% of zinc, 0.1% of iron, 0.03% of copper, 1-2% of sodium, 0.02% of magnesium and 0.01% of calcium. This conventional process cannot recover the acid in the pickling wastewater, and requires a large amount of calcium oxide for neutralization, which is costly, produces a large amount of solid waste, and cannot recover the heavy metals in the wastewater, so that improvement is urgently needed.

There is therefore a need to propose a solution to this problem.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a process for recovering valuable metals from smelting waste liquid, which reduces the acid concentration in the waste liquid through the adsorption of acid-absorbing resin and multiple times of filter pressing of a filter press, reduces the pollution of the waste liquid discharge to the environment, and can effectively recover the valuable metals in the waste liquid.

The technical purpose of the invention is realized by the following technical scheme: the process for recovering valuable metals from smelting waste liquid comprises the following steps: 1) carrying out circulating concentration and primary filter pressing on the acidic wastewater generated by purification and washing in a purification system, reducing emission of primary clear liquid by 80-85%, and recovering waste residues generated by primary filter pressing; 2) adding acid-absorbing resin into the primary clear liquid to absorb acid in the primary clear liquid, adding an oxidant to oxidize bivalent iron in the primary clear liquid into trivalent iron ions to obtain secondary clear liquid and waste acid, adding iron yellow seed crystals to perform a heating reaction, adjusting the pH value to 1.5-4.5, and separating out iron in the waste acid in the form of iron yellow; 3) adding zinc powder into the secondary clear liquid to replace copper in the secondary clear liquid, adding a flocculating agent into the secondary clear liquid for many times in the replacement process, stirring by using a stirring device, adjusting the pH value of the secondary clear liquid after copper precipitation to 6.5-8.0, and precipitating zinc hydroxide to obtain barren liquor; 4) and (3) carrying out filter pressing on the barren solution by a filter press again, adding an alkaline solution into the barren solution subjected to filter pressing for size mixing and neutralization, and discharging after the pH value reaches the standard.

The invention is further configured to: the alkaline solution in the step 4) is sodium sulfide.

The invention is further configured to: the volume ratio of the barren solution to the sodium sulfide solution in the step 4) is 60-225:1, so that the removal rate of cadmium elements in the acid wastewater can be ensured to be more than 98%, and the removal rate of iron and zinc elements can be more than 99%.

The invention is further configured to: the size mixing concentration in the step 4) is 30-50 wt%.

The invention is further configured to: the components of the acidic wastewater in the step 1) are as follows: 15-30g/L of sodium hydroxide, 1-3g/L of sodium cyanide, 0.01-0.03mg/L of gold, 0.10-0.50mg/L of silver, 3-6g/L of copper and 3-5g/L of zinc.

The invention is further configured to: the flocculating agent in the step 3) is a mixture of sodium sulfide and aluminum sulfate.

The invention is further configured to: the acid absorption resin in the step 2) is a tough gel body strong base type anion exchange resin with a polystyrene framework containing quaternary amine II type functional groups.

In conclusion, the invention has the following beneficial effects:

1. the acid concentration in the waste liquid can be effectively reduced through multiple times of filter pressing, absorption of acid-absorbing resin and alkaline neutralization of sodium sulfide, so that the waste liquid can reach the discharge standard, and the pollution of the waste liquid to the environment is reduced;

2. valuable metals such as copper, iron, zinc and the like in the waste liquid can be fully recycled, and the recovery rate of the valuable metals in the waste liquid is improved.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the present invention is further described in detail with reference to specific embodiments, and it should be noted that the embodiments and features of the embodiments of the present application can be combined with each other without conflict.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "sleeved/connected," "connected," and the like are to be construed broadly, e.g., "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The present invention will be described in detail with reference to examples.

The process for recovering valuable metals from smelting waste liquid comprises the following steps: 1) carrying out circulating concentration and primary filter pressing on the acidic wastewater generated by purification and washing in a purification system, reducing emission of primary clear liquid by 80-85%, and recovering waste residues generated by primary filter pressing; 2) adding acid-absorbing resin into the primary clear liquid to absorb acid in the primary clear liquid, adding an oxidant to oxidize bivalent iron in the primary clear liquid into trivalent iron ions to obtain secondary clear liquid and waste acid, adding iron yellow seed crystals to perform a heating reaction, adjusting the pH value to 1.5-4.5, and separating out iron in the waste acid in the form of iron yellow; 3) adding zinc powder into the secondary clear liquid to replace copper in the secondary clear liquid, adding a flocculating agent into the secondary clear liquid for many times in the replacement process, stirring by using a stirring device, adjusting the pH value of the secondary clear liquid after copper precipitation to 6.5-8.0, and precipitating zinc hydroxide to obtain barren liquor; 4) and (3) carrying out filter pressing on the barren solution by a filter press again, adding an alkaline solution into the barren solution subjected to filter pressing for size mixing and neutralization, and discharging after the pH value reaches the standard.

The alkaline solution in the step 4) is sodium sulfide.

The volume ratio of the barren solution to the sodium sulfide solution in the step 4) is 60-225:1, so that the removal rate of cadmium elements in the acid wastewater can be ensured to be more than 98%, and the removal rate of iron and zinc elements can be more than 99%.

The size mixing concentration in the step 4) is 30-50 wt%.

The components of the acidic wastewater in the step 1) are as follows: 15-30g/L of sodium hydroxide, 1-3g/L of sodium cyanide, 0.01-0.03mg/L of gold, 0.10-0.50mg/L of silver, 3-6g/L of copper and 3-5g/L of zinc.

The flocculating agent in the step 3) is a mixture of sodium sulfide and aluminum sulfate.

The acid absorption resin in the step 2) is a tough gel body strong base type anion exchange resin with a polystyrene framework containing quaternary amine II type functional groups.

The acid wastewater is subjected to two times of filter pressing by a filter press to reduce the acid concentration in the acid wastewater and suspended particles of minerals, reduce the pollution caused by the discharge of the acid wastewater, and the acid absorption resin is used for absorbing the primary clear liquid, so that the content of acidic substances in the acidic wastewater can be further reduced, and the valuable metals such as copper, iron, zinc and the like in the acid waste liquid are effectively recovered through the replacement of the oxidant and the zinc powder, so that the valuable metals in the acid waste liquid can be fully recycled, the waste of resources is reduced, the sodium sulfide added into the barren solution is subjected to a sulfuration reaction with the acidic wastewater in years, so that the residual valuable metals in the barren solution can be further extracted, the recovery rate of the valuable metals is improved, and because the sodium sulfide is alkaline, the barren solution can be neutralized simultaneously, so that the pollution to the environment can be reduced after the barren solution is discharged.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.