Pêvajoya Pêvajoya Dermankirina Avê Derxistina Zêrîn a Sîyanîdê

At preseNt, the siyanurDerxistina zêr method is one of the MAin Pêvajoya Maturees ji bo Zêrîn Smelting in çîn. Ew hewcedariyênçareseriya siyanide derxistin zêr from ores, featuring high rêjeya başbûnê, strong adaptability to ore Properties, and the ability to produce gold on - site. Since the first use of siyanur solution to lePişkirin gold from ores in 1887. this method has been widely applied until now. However, Derxistina Zêrê Siyanid generates a large amount of toxic and harmful substances, posing a huge threat to the surrounding dor and humans. Therefore, in order to reduce the harm, it is necessary to study the Rêbazên dermankirinê of Derxistina zêr a siyanûrê xûrdekirinîav. A large number of researchers have summarized the treatment methods, chemical prinCIPles, and development trends of Siyanid - ava çopê heye, but most of them only discuss one or two methods. Therefore, this article conducts a detailed analysis of various treatment methods for Cyanidederxistina zêr wastewater currently applied in ava, compares the advantages, disadvantages, and application scenarios of each method, which has certain guiding significance for similar sepanên bi rastî çêkerî.

I. Sources and Xeteran of Cyanide Derxistina zêr Wastewater

The main principle of cyanide Derxistina zêrn is that in an aerobic envhesinderewan dike, siyanid sodyûm reacts with gold to form kompleksa zêres, which are then dissolved. After that, gold can be extracted by enrichment through activated KarbonatAdsorption or displaced by çingo powder from gold cyanide. At the same time, other Metirsên giran wekî zîv, Sifir, û Çingo also form complexes and dissolve.

Ew siyanid de tê bikar anîn bersivî and the complexes produced are all toxic and harmful substances. Sodyûm siyanid is easy to hydrolyze and is a Class 1 pir jehrî substance, with a lethal dose of 0.10g. When Cyanides leak into water bodies, it is extremely detrimental to the organisms in the water, and will cause a huge threat to humans and the surrounding envhesinment. Therefore, the treatment of cyanide gold extraction wastewater is of great importance.

II. Rêbazên Dermankirinê yên Sereke yên Ji bo Avêtina Zêrîn a Sîyanîdê

Rêbaza Klorînê ya Alkaline

Ew rêbaza klorkirina alkalîn is currently one of the most commonly used methods for treaqûtîkg cyanide - containing wastewater from cyanide gold extraction. It mainly uses Kllorine - bingehd oxidants to oxidize the siyanid in the wastewater under alkaline conditions, converqûtîkg them into non - toxic substances. The cyanide - breaking process of alkaline chlorination is divided into two stages:

The first stage is to oxidize cyanide to cyanate, which is called the “incomplete oxaxation” stage. CN⁻ reacts with OCl⁻ to first form CNCl, and then it hydrolyzes to CNO⁻. It should be noted that CNCl is highly volatile and toxic under tirşic conditions. Therefore, during operation, the nirxa pH must be strictly controlled to be in an dewleta alkaline.

The second stage is to further oxidize cyanate to carbon dioxide and nitrogen, which is called the “complete oxidation” stage. During the cyanide - breaking process, the pH value has a great imPACt li ser Reaksiyona Oksîdasyonê. The pH value of the first - stage oxidation should be controlled at 10 - 11. and the reaction time is 10 - 15 minutes. The pH value of the second - stage oxidation should be controlled at 6.5 - 7.0. and the reaction time is 10 - 15 minutes.

A certain mine uses the alkaline chlorination method to treat the sUPernatant of cyanide tail slurry (with a cyanide content of 200mg/L) and the seepage water from the Rûniştin tank (with a cyanide content of 5mg/L). The pH value is controlled at 10 - 11. and toza spîkirinê is added at a ratio of 35 - 40 times the cyanide content for mixing and stirring. After sedimentation in a Zûtir, the total cyanide content can be reduced to 0.1mg/L.

The alkaline chlorination method is the most commonly used method for treating cyanide - containing wastewater, and spî kirin powder is the most commonly used chlorine - based Oxidant. This method is suitable for treating cyanide gold extraction wastewater with high or low concentrations. It can also remove thiocyanate and cyanide - containing complexes (except for ferrocyanide complexes). The medicament is widely available, the generated waste residue is easy to filter, and the operation is simple. However, the operation envHesinment is relatively harsh when using Spî kirin powder to treat wastewater. Now some enterprises use bLeaching liquid or chlorine dioxide insÇAYd, which improves the operation environment to some extent. But toxic gases are generated during the reaction process, and it has a relatively large qirêjkerness to equipment. The medicament cost and maintenance cost are relatively high.

Ferrous Salt Complexation Awa

The ferrous salt complexation method is a treatment method for cyanide gold extraction wastewater that has emerged in recent years. By controlling the reaction pH value at 7 - 8. ferrous ions react with Siyanûra azad and some cyanide complexes in the cyanide gold extraction wastewater to form precipitates.

Experiments have shown that generally, adding only Sulfatê Ferrous to treat cyanide gold extraction wastewater cannot make the wastewater meet the discharge standards. Therefore, a general oxidant needs to be added to the treated wastewater for deep - Rakirina Sîyanûrê. As long as the conditions are well - controlled, the oxidant can be directly added for treatment without separating the precipitate, and the discharge standard can also be achieved. This has positive significance compared with the traditional method of veqetandinî first and then treatment.

A certain gold smelter uses the sodyûm sulfîd - sulfate fer method to treat cyanide - poor liquid. The influent has a cyanide content of 2500mg/L. After treatment, the effluent has a cyanide content of less than 20mg/L, with a removal rate of 99.2%, showing remarkable results. The subsequent deep - treatment uses the metabisulfite sodyûm - air method to reduce the total cyanide to less than 0.4mg/L.

The ferrous salt complexation method is a newly emerging treatment method, mainly used to treat high - concentration cyanide - containing wastewater. Its process is simple, the one - time investment is small, it is easy to operate, the medicament (mainly ferrous Sulfat) is widely available, inexpensive, and easy to use. However, because the ferrous sulfate solution is acidic, when it is mixed with cyanide gold extraction wastewater, the local area becomes acidic, and there is a possibility of generating gaza hîdrojen sîanîd. Moreover, it cannot remove thiocyanate, and the treated wastewater still needs deep treatment to meet the discharge standards.

Metabisulfîta sodyûmê - Air Method

Ew sodium metabisulfite - air method is developed from the dîoksîdê kewkurtê - air method. It mainly uses the synergistic effect of sodium metabisulfite and air on the Cyanides in the wastewater within a certain pH range, with the catalytic effect of Îyonên sifir, to oxidize CN⁻ to CNO⁻.

If the cyanide content in the cyanide - containing wastewater is high, pre - treatment can be carried out first to reduce the total kombûna siyanîdê to less than 100mg/L. Then, sodium metabisulfite and Sulfata sifir are added, sufficient air is introduced, and the pH value is controlled (generally controlled at 7 - 8), so that cyanide is oxidized to cyanate, which is then hîdrolîze kirin to form bicarbonate ions and amonyak.

Ew Sodium metabisulfite - air method is suitable for treating low - concentration cyanide gold extraction wastewater. The pîvanîk of the medicament is small, the labor intensity is low, but the upfront investment is relatively large, and equipment such as blowers needs to be added. The pêwîstiyên for process indicators are relatively strict, and controlling the pH value is very crucial. sifir sulfate also needs to be added as a katalîtal. The reaction time is long. If the treatment is not proper, a large amount of ammonium ions will be generated, and the generated slag is not easy to filter. There is a small amount of ammonia gas generated on - site, and it has no effect on removing thiocyanides.

Rêbaza Oksîdasyona Hîdrojen Peroksîdê

Ew hîdrojen peroxideRêbaza oksîdasyonê is to oxidize cyanides to CNO⁻ under normal temperature, alkaline (pH = 10 - 11) conditions, with Cu²⁺ as a Katalîstan, and then hydrolyze them into non - toxic substances. Complex cyanides (complexes of Cu, Zn, Pb, Ni, Cd) are also dissociated due to the destruction of cyanides in them. Ferroîyonên siyanidê û yên din H.E.A.vy Îyonên metal form ferrocyanide complex salts and are removed. Finally, the total Tevliheviya Siyanide in the treated wastewater can be reduced to less than 0.5mg/L.

This method is suitable for treating low - concentration cyanide - containing wastewater. The Piyoxa Hydrogen treatment equipment is simple and easy to achieve automatic control. However, the generated cyanate needs to stay for a certain period of time to decompose into CO₂ and NH₃. The disadvantages are that using copper as a catalyst may cause copper in the discharged water to exceed the standard, the madeya xav cost is relatively high, thiocyanides cannot be oxidized, and ammonium ions are generated. In fact, the wastewater still has a certain zordariyê. Moreover, since Peroxide hydrogen is an oxidant, it has large corrosiveness, and there are certain difficulties and dangers in Ragihandinê û bikar bînin.

Rêbaza asîdkirinê

When using the acidification method to treat cyanide - poor liquid, its reaction MEChanism is relatively complex, mainly including three pêvajoyên: the acidification process of cyanide - containing wastewater, the stripping and absorption process of HCN gas, and the neutralization process of the stripped liquid.

(1) Acidification reaction: The cyanide - poor liquid is acidified and purified with acid. The complex cyanides in the poor liquid will form inavêde precipitates such as CuCN, CuSCN, and Zn₂Fe(CN)₆ and be removed, and at the same time, Hîdrojen hîdrojen tê çêkirin.

(2) Volatilization and absorption reaction: The poor liquid is pre - heated to about 30℃ before acidification. Since the xala kelandinê of HCN is only 26.5℃, it is extremely volatile. Therefore, a packed tower is used as the mass - transfer equipment for the contact between the gas - liquid two - phase in the acidification method, which is easy to achieve the stripping and absorption of HCN.

(3) Neutralization reaction: Lime or liquid alkali is used to bêalî kirin the acid - stripped residual liquid. The residual HCN molecules in the solution will be converted into the CN⁻ form. The acidification method can recover Sodyum Syanide from the cyanide - containing wastewater and realize resource rawesta. However, it has high requirements for equipment sealing, a relatively large upfront investment, requires high - level operation skills, and equipment maintenance is difficult. There are also certain ewlekarîtalûkes. The wastewater generated after recovery still needs deep treatment to meet the discharge standards.

electrolysis Awa

Rêbaza elektrolîzê reaksiyonên redoksî yên elektrokîmyayî bikar tîne da ku siyanîdên di ava çopê de hilweşîne. Di dema elektrolîza îyonan de, siyanîd elektronan li anodê winda dikin û dibin siyanat, karbonat, nîtrojen an amonyûmê. Cyanate bêtir bi CO2 û H2O ve tê oksîd kirin. Reaksiyonên sereke ev in:

CN- + 2OH- - 2e → CNO- + H24O (XNUMX)

2CN- + 4OH- - 6e → 2CO₂ + N2 + 25HXNUMXO (XNUMX)

Electrolysis experiments using a self - made ceramic - based gûlle dioxide electrode rod and a stainless - steel cathode plate have proven that by using the electrolysis method to treat cyanide - containing wastewater, after 2 hours of electrolysis, the CN⁻ concentration can be reduced from 385mg/L to 58mg/L, and the Cu²⁺ concentration can be reduced from 450mg/L to 48mg/L. In addition, Hunan Zhongnan Gold Smelter uses the electrochemical method to treat cyanide gold extraction wastewater, which can reduce the total cyanide from 4g/L to 0.8g/L. The difference from the above is that both the anode and cathode plates are made of iron plates. During the operation process, not only electric energy is consumed, but also the iron plates are consumed.

Rêbaza elektrolîzê bi giranî ji bo dermankirina ava çopê ya bi giraniya siyanîdê tê bikar anîn. Amûr deverek piçûk dagir dike, pêvajo hêsan û hêsan e ku meriv kontrol bike, lê ew gelek enerjiya elektrîkê vedixwe, û lêçûna xebitandinê ji ya rêbaza klorîna alkaline mezintir e. Rêjeya rakirina siyanide navîn e, û ew ti bandorek li ser rakirina kompleksên siyanîdê nake.

At present, among the treatment methods for cyanide gold extraction wastewater, the alkaline chlorination method, acidification method, and sodium metabisulfite - air method are widely used. The electrolysis method and ferrous salt complexation method are newly emerging methods that have been successfully applied in industrial treatment. The Hydrogen peroxide oxidation method is mainly an Dermankirina Acîl method. There are many other treatment methods for treating cyanide gold extraction wastewater, such as natural paqijkirin method, biological method, membrane veqetandinî method, ion - exchange method, hwd. Lê belê, wekî sepanên pîşesazî, they all have certain limitations and still need continuous improvement.