Method for removing heavy metals from high-concentration cyanide-containing wastewater in gold production through cyanide breaking

Abstract

The invention relates to a method for removing heavy metals from high-concentration cyanide-containing wastewater in gold production through cyanide breaking, and belongs to the technical field of cyanide-containing wastewater treatment. The method comprises the following steps: S1, flocculent precipitation; S2, electrolysis; S3, primary natural precipitation; S4, primary cyanide breaking; S5, secondary natural precipitation; S6, iron removal; S7, secondary cyanide breaking; and S8, precipitation treatment. Heavy metal solids generated in the electrolysis process can be separated through one-time precipitation, so recovery treatment of heavy metal is facilitated; a third supernatant is subjected to iron removal treatment by using an iron removal catalyst after secondary precipitation, so that the iron element in the cyanide-containing wastewater can be effectively removed, and the pollution load of subsequent secondary cyanide breaking treatment is reduced; and CN<-> which is not treated by primary cyanide breaking can be further removed by adopting secondary cyanide breaking, so that the difficulty of subsequent treatment is reduced. Compared with other methods for removing cyanogen and removing heavy metals, the method has the advantages of being simple and feasible, stable in reaction process and free of secondary pollution.

Description

technical field

[0001] The invention relates to the technical field of cyanide-containing wastewater treatment, in particular to a method for breaking cyanide and removing heavy metals from high-concentration cyanide-containing wastewater in gold production. Background technique

[0002] Cyanide-containing wastewater is generated during the gold production process, and the cyanide-containing wastewater usually carries heavy metals, especially gold and silver, which are easily discharged along with the wastewater, causing waste of resources.

[0003] At present, the main methods for treating high-concentration cyanide-containing waste liquid produced in the gold production process at home and abroad include chlorination, acidification, sulfur dioxide-air oxidation, activated carbon adsorption and precipitation. There are following disadvantages respectively:

[0004] The disadvantages of the chlorination method are: 1. If the equipment is not well sealed during the wastewate...

Examples

Embodiment 1

[0042] The method for breaking cyanide and removing heavy metals in high-concentration cyanide-containing wastewater in gold production of the present embodiment comprises the following steps:

[0043] S1. Flocculation and precipitation: under the condition of 20°C, put 2L of high-concentration cyanide-containing wastewater into the thickener, and add polyaluminum chloride (PAC) for flocculation and precipitation to obtain the first supernatant;

[0044] S2. Electrolysis: overflow the above first supernatant into the electrolytic cell, and remove the heavy metal Cu by electrolysis at pH=4 2+ , the time of electrolysis reaction is 1h, obtain electrolyte;

[0045] S3, a natural precipitation: adjust the above electrolytic solution to the alkalinity of pH=10, put it into a thickener for natural precipitation, the pH of the natural precipitation is 10, and obtain the second supernatant;

[0046]S4, primary cyanide breaking: overflow the above second supernatant to the cyanide bre...

Embodiment 2

[0057] The method for breaking cyanide and removing heavy metals in high-concentration cyanide-containing wastewater in gold production of the present embodiment comprises the following steps:

[0058] Flocculation and precipitation: under the condition of 20°C, pour 50L of high-concentration cyanide-containing wastewater into the thickener, and add polyaluminum chloride (PAC) for flocculation and precipitation to obtain the first supernatant;

[0059] Electrolysis: The above-mentioned first supernatant is overflowed into the electrolytic cell, and the heavy metal Cu is electrolyzed at pH=4 2+ , the time of electrolysis reaction is 1h, obtain electrolyte;

[0060] One-time natural precipitation: adjust the above electrolyte to the alkalinity of pH=10, put it into a thickener for natural precipitation, the pH of the natural precipitation is 10, and obtain the second supernatant;

[0061] Primary cyanide breaking: overflow the above-mentioned second supernatant to the cyanide b...

Embodiment 3

[0072] The method for breaking cyanide and removing heavy metals in high-concentration cyanide-containing wastewater in gold production of the present embodiment comprises the following steps:

[0073] Flocculation and precipitation: under the condition of 20°C, pour 1000L of high-concentration cyanide-containing wastewater into the thickener, and add polyaluminum chloride (PAC) for flocculation and precipitation to obtain the first supernatant;

[0074] Electrolysis: The above-mentioned first supernatant is overflowed into the electrolytic cell, and the heavy metal Cu is electrolyzed at pH=4 2+ , the time of electrolysis reaction is 1h, obtain electrolyte;

[0075] One-time natural precipitation: adjust the above electrolyte to the alkalinity of pH=10, put it into a thickener for natural precipitation, the pH of the natural precipitation is 10, and obtain the second supernatant;

[0076] Primary cyanide breaking: overflow the above-mentioned second supernatant to the cyanide...

technical field

[0001] The invention relates to the technical field of cyanide-containing wastewater treatment, in particular to a method for breaking cyanide and removing heavy metals from high-concentration cyanide-containing wastewater in gold production. Background technique

[0002] Cyanide-containing wastewater is generated during the gold production process, and the cyanide-containing wastewater usually carries heavy metals, especially gold and silver, which are easily discharged along with the wastewater, causing waste of resources.

[0003] At present, the main methods for treating high-concentration cyanide-containing waste liquid produced in the gold production process at home and abroad include chlorination, acidification, sulfur dioxide-air oxidation, activated carbon adsorption and precipitation. There are following disadvantages respectively:

[0004] The disadvantages of the chlorination method are: 1. If the equipment is not well sealed during the wastewate...

Examples

Embodiment 1

[0042] The method for breaking cyanide and removing heavy metals in high-concentration cyanide-containing wastewater in gold production of the present embodiment comprises the following steps:

[0043] S1. Flocculation and precipitation: under the condition of 20°C, put 2L of high-concentration cyanide-containing wastewater into the thickener, and add polyaluminum chloride (PAC) for flocculation and precipitation to obtain the first supernatant;

[0044] S2. Electrolysis: overflow the above first supernatant into the electrolytic cell, and remove the heavy metal Cu by electrolysis at pH=4 2+ , the time of electrolysis reaction is 1h, obtain electrolyte;

[0045] S3, a natural precipitation: adjust the above electrolytic solution to the alkalinity of pH=10, put it into a thickener for natural precipitation, the pH of the natural precipitation is 10, and obtain the second supernatant;

[0046]S4, primary cyanide breaking: overflow the above second supernatant to the cyanide bre...

Embodiment 2

[0057] The method for breaking cyanide and removing heavy metals in high-concentration cyanide-containing wastewater in gold production of the present embodiment comprises the following steps:

[0058] Flocculation and precipitation: under the condition of 20°C, pour 50L of high-concentration cyanide-containing wastewater into the thickener, and add polyaluminum chloride (PAC) for flocculation and precipitation to obtain the first supernatant;

[0059] Electrolysis: The above-mentioned first supernatant is overflowed into the electrolytic cell, and the heavy metal Cu is electrolyzed at pH=4 2+ , the time of electrolysis reaction is 1h, obtain electrolyte;

[0060] One-time natural precipitation: adjust the above electrolyte to the alkalinity of pH=10, put it into a thickener for natural precipitation, the pH of the natural precipitation is 10, and obtain the second supernatant;

[0061] Primary cyanide breaking: overflow the above-mentioned second supernatant to the cyanide b...

Embodiment 3

[0072] The method for breaking cyanide and removing heavy metals in high-concentration cyanide-containing wastewater in gold production of the present embodiment comprises the following steps:

[0073] Flocculation and precipitation: under the condition of 20°C, pour 1000L of high-concentration cyanide-containing wastewater into the thickener, and add polyaluminum chloride (PAC) for flocculation and precipitation to obtain the first supernatant;

[0074] Electrolysis: The above-mentioned first supernatant is overflowed into the electrolytic cell, and the heavy metal Cu is electrolyzed at pH=4 2+ , the time of electrolysis reaction is 1h, obtain electrolyte;

[0075] One-time natural precipitation: adjust the above electrolyte to the alkalinity of pH=10, put it into a thickener for natural precipitation, the pH of the natural precipitation is 10, and obtain the second supernatant;

[0076] Primary cyanide breaking: overflow the above-mentioned second supernatant to the cyanide...