硫代硫酸盐是含有S2O3基团的化合物,它可看做是硫酸盐中一个氧原子被硫原子取代的产物。硫代硫酸盐与酸作用时形成的硫代硫酸立即分解为硫和亚硫酸，后者又立即分解为二氧化硫和水， 因而浸出过强需要在碱性条件下进行。SoF中两个S原子的氧化值平均为+2,它具有温和的还原性，因此，浸出过程适当地控制氧化条件是必须的。硫代硫酸盐另一重要性质是它能与许多金属 (金、银、铜、铁、铂、钯、汞、镍、锡)离了形成络合物。如:
石硫合剂中含有S.、S0X、5、S等离子，它们与金均可形成稳定的配合物。多硫离子如同过氧离子，其有氧化性，可将Au(0)氧化成Au(I),生成的Au( I)可与溶液中各种配位离子形成稳定的配合物，由于Au( I)浓度不断降低，就促使Au(0)不断溶解。浸出金的关键不但要有氧化剂使Au(0)氧化，更重要的是被氧化了的Au( I)与溶液中的配位离了生成稳定的配合物。氰化物和硫脲(Thio) 是最常见的浸出金溶剂，在氧化剂存在下它们与Au (I)均能形成稳定的配合物。S205、S3、S2-与Au(T)形成的配合物,其稳定性均高于硫脲与Au(I )的配合物，接近氰化物与金的配合物。
用于液氧化法的浸出剂主要是(湿) 氯和氯盐。由于氯的活性 渣浆泵
安徽快3开奖结果What is thiourea leaching of gold ore by slurry pump
Gold leaching by thiourea method refers to the process of leaching gold by thiourea.
Thiourea, also known as urea sulfide (h2ncsnh2), is an organic compound with a molecular weight of 76.12, a density of 1.405g/cm3, and a melting point of 180-182c. The crystal is easily soluble in water. At 25C, the solubility in water is 142g / L, and the aqueous solution is neutral and non corrosive. The important characteristic of the solution heat of 22.57k/mol sulfur suit is the formation of stable complex cations with transition metal ions in the aqueous solution. General formula:
Sulfur removal is not stable in alkaline solution, it is easy to decompose into sulfide and cyanamide, and cyanamide hydrolysis produces urea。 Thiourea has reductive property in acid solution and is easy to oxidize to form dithioformamidine。 Thioformamidine is further oxidized and decomposed into cyanamide and elemental sulfur。
What are the characteristics of thiourea?
The characteristics of thiourea are as follows: ① it is nontoxic; ② it has better selectivity than cyanide, and it is good for copper, zinc, arsenic and antimony
The sensitivity of other elements is obviously lower than that of oxidation method; ③ the gold dissolving speed is faster than that of cyanidation leaching by more than 4-5 times; ④ the gold dissolving by thiourea is carried out in acid medium。 It is suitable for the leaching of refractory minerals which have been pretreated; ⑤ the thiourea gold complex formed in the solution is cation in nature, which is suitable for the recovery of gold by solvent extraction and ion-exchange method, but thiourea is expensive and consumes a large amount (20% oxidized by itself and 80% absorbed by ore)。 It is not as stable as cyanide, and it is easy to corrode the equipment due to the leaching of gold in acid medium In recent years, sulfur pulse has been listed as a suspicious carcinogen。 Therefore, it can be said that thiourea method is difficult to replace cyanidation in the near future。 The leaching of gold and silver with thiourea acid solution has the characteristics of high design speed, small toxic parts, easy regeneration and recovery of reagents, and little green effect of copper, arsenic, antimony, carbon, lead, zinc and sulfur。 It is suitable for extracting gold bearing mineral raw materials that are difficult to be treated or cannot be treated by chlorination method
What is thiosulfate leaching of gold?
安徽快3开奖结果Thiosulfate is a compound containing s2o3 group, which can be regarded as the product of one oxygen atom in sulfate replaced by sulfur atom. The thiosulfuric acid formed by the interaction of thiosulfate and acid is immediately decomposed into sulfur and sulfite, and the latter is immediately decomposed into sulfur dioxide and water. The average oxidation value of two S atoms in sof is + 2, which has mild reducibility. Therefore, it is necessary to properly control the oxidation conditions in the leaching process. Another important property of thiosulfate is that it can form complexes with many metals (gold, silver, copper, iron, platinum, palladium, mercury, nickel, tin). Such as:
安徽快3开奖结果The most important thiosulfate is sodium thiosulfate and ammonium thiosulfate, both of which are usually colorless or white granular crystals。 In the presence of oxygen, gold may react in thiosulfate solution as follows:
What is the method of leaching gold with stone sulfur mixture?
The leaching of gold by the method of stone sulfur mixture is a new type of non system leaching technology. Stone sulfur
It is made of cheap and easily available lime and sulfur yellow. It is nontoxic and beneficial to environmental protection. Its main components are calcium polysulfide (CAS,) and calcium thiosulfate (cas2o3). Therefore, the process of gold leaching by the method of stone sulfur mixture is the combination of polysulfide leaching and thiosulfate leaching. Therefore, the method of stone sulfur mixture has superior gold leaching performance and is more suitable for the treatment of refractory gold ores containing carbon, extension, antimony, copper and dislocation. However, this method is not mature in technology and needs further study.
There are S., s0x, 5, s plasma in the mixture, which can form stable complexes with gold. Polysulfide ions, like peroxides, are oxidable. They can oxidize Au (0) to Au (I). The resulting Au (I) can form stable complexes with various coordination ions in the solution. As the concentration of Au (I) keeps decreasing, Au (0) will continue to dissolve. The key to gold leaching is not only the oxidizer to oxidize Au (0), but also the coordination of oxidized Au (I) and solution to form stable complexes. Cyanide and thiourea are the most common solvent for leaching gold. In the presence of oxidant, they can form stable complexes with Au (I). The stability of the complexes of S205, S3, S2 - with Au (T) is higher than that of thiourea with Au (I), close to that of cyanide with gold.
29 what is liquid chlorine leaching?
Liquid chlorination, also known as water solution chlorination or water chlorination. In the initial stage of this method, gold was successfully leached from the solution with cyanogen water or sulfuric acid plus bleaching powder, and gold was precipitated from the leached solution with ferrous sulfate. Generally speaking, all the substances soluble in aqua regia in raw materials can also be dissolved by liquid cyanidation. The leaching rate of gold is higher and the price of chlorine is lower than that of cyanide.
Chlorine is a strong oxidant and can react with most elements。 For gold, it is both a water oxidizer and a complexing agent。 Gold is oxidized by chlorination and complexed with chlorine, so it is called water chlorination leaching gold。 Its chemical reaction is
The reaction was carried out rapidly under the condition of low pH, when the concentration of chlorine in the solution increased obviously.
The main leachables used in liquid oxidation are (wet) chlorine and chloride salts。 Active slurry pump due to chlorine