Copper ore removal process technology

First, the floatability of arsenopyrite

Aromatic sand is the most widely distributed sulfur- arsenic compound, which is divided into FeAsS and contains As46%. The poisonous sand is more common in high-temperature hydrothermal deposits and is symbiotic with copper , lead , zinc and other sulfides. According to statistics, the As/Cu ratio in the 15% copper resources in the world is 1:5, 30% cobalt resources. For a 2:1, 10% tin resource has an As/Sn ratio of 10:1. Because the formation conditions of the arsenopyrite are similar to these minerals, it often enters the concentrate during the sorting process, causing the arsenic content of the sulfide ore concentrate to meet the smelting requirements.

There are three main sources of arsenic in copper concentrates: (1) Arsenic exists in copper minerals in the form of isomorphism. It cannot be separated by flotation, but it usually has little effect on arsenic in copper concentrate. (2) Arsenic-containing copper minerals - arsenic bismuth copper ore, sulphur arsenic copper ore, etc. are enriched in copper concentrates. (3) Arsenic-containing minerals - mainly mixed with arsenopyrite. How to solve the separation of copper minerals and arsenopyrite is the main measure to reduce arsenic in copper concentrates.

The floatability of arsenopyrite is similar to that of other sulfide minerals. It is very buoyant in weakly acidic media, and its floatability is reduced by pH>7. The flotation collector is a thio compound. Metal ions (e.g., Cu ^{2 +)} strong activation of arsenopyrite flotation, the arsenopyrite surface after activation ² Cu ⁺ copper minerals having similar floatability. Studies have shown that the activation of arsenopyrite by Cu ^{2 +} is due to its selective adsorption on the crystal lattice of arsenic minerals, which becomes a place to firmly fix xanthate, so that the arsenopyrite obtains good floatability, which causes copper arsenic. Difficulties in the separation of minerals.

Second, copper and arsenic separation

The separation of copper and arsenic is mainly to solve the problem of separation of copper minerals and arsenopyrite, which can be summarized as follows:

(1) Highly selective collectors. It is important to use selective collectors to expand the sorting of the two minerals. For example, a combination of xanthate and butyl ammonium black drug, a mixture of xanthate and sulfur and nitrogen, butyric acid ester (OSN-43), anthranol xanthate, and phosphoaminophenol are better for a particular ore under certain conditions. The selectivity. Auxiliary collectors such as DPG or 8-hydroxyquinoline can be added to the mill together with the inhibitor to improve sorting efficiency and precious metal recovery.

(2) Lime-based combination inhibitor: Lime is a commonly used alkaline pH adjuster, which can increase the pH value of the slurry and also promote the dissolution or oxidation of the mineral surface. However, the amount of lime should be carefully controlled, and if it is excessive, it will also have a certain inhibitory effect on copper sulfide minerals. Therefore, when the single lime suppression effect is not good, other inhibitors such as sodium cyanide, zinc sulfate, and SO ₂ may be used. Studies have shown that lime -SO ₂ -Zn (CN) ₂ ^- complex combination of agents in combination, the most effective inhibition arsenopyrite. When the ore contains a large amount of secondary copper minerals, when the aerated sand is activated by Cu ^{2 + and the} floatability is high, lime can be used together with sodium sulfide; at this time, S ^{2 -} and Cu ^{2 + form} insoluble precipitates, thereby eliminating Cu ^{2 +} activation.

(3) Oxidation method: The poisonous sand is easy to oxidize, and the aerobic oxidation (pH 5.7-6.5), long-time stirring or adding various oxidants can strongly suppress the floatability of the arsenopyrite. Commonly used bleach oxidant, potassium permanganate, potassium weight chromium and manganese dioxide, the strength of the order of several oxidants are: bleach> potassium permanganate> potassium dichromate> manganese dioxide.

Increasing the temperature of the slurry accelerates the oxidation process. Experimental work has shown that a large number of, in the case where the temperature increase of the pulp, by oxidation of sulfide minerals sequential part degree of intensity is: arsenopyrite> pyrrhotite> chalcopyrite. The control temperature is 40 to 50 ° C, which can strengthen the inhibition of poisonous sand.

(IV) Inorganic inhibitors such as sulphuric acid: Inhibition of arsenopyrite with sulphuric acid or thiosulfate. The test results show that the order of inhibition of toxic sand is: Knox drug Liu > sodium thiosulfate > sodium sulfite.

(5) Organic Inhibitors: In addition to inorganic inhibitors, from the perspective of environmental protection, there is a growing interest in finding new and effective effective organic inhibition. Organic inhibitors of arsenopyrite include dextrin, tannin, lignosulfonate, polyacrylamide, etc., and it has been found that the combination of an organic inhibitor and an inorganic agent has an obvious effect.

Third, the practice of copper sulfide arsenic ore separation

The research results at home and abroad show that the separation of arsenopyrite and copper sulfide minerals can be completely realized by using the existing beneficiation technology .

Japan has reported that for copper and arsenic mixed concentrates that have been adsorbed, chalcopyrite and arsenopyrite are in an easy-floating state. Lime and sodium cyanide can be added to the mixed concentrate, and the pH is stirred in the range of 10.5 to 11.5. Then, the pH is adjusted to a weak acid pH of 5 to 7 by using sulfuric acid or SO ₂ , and the two minerals are separated by using only a foaming agent to float the chalcopyrite without adding a collector. The result is that when the copper-arsenic mixed concentrate contains 3.81% copper and 15.28% arsenic, the copper concentrate grade is 19.4%, the arsenic content is 0.24%, the copper operation recovery rate is 92.4%, the arsenic concentrate grade is 18.6%, and the copper content is 0.35. %, arsenic recovery rate is 92%.

The country has also made great progress in the copper-arsenic separation process. For example, the Jiangxi Fuyang copper mine is used in the weak acid medium with pH=5-7.0, and the sulfite-lime method is used to suppress the arsenopyrite and pyrite. The methyl thiourethane and the xanthate flotation copper minerals, when the ore contains 0.7% arsenic, the copper concentrate contains less than 0.3% arsenic, and the copper recovery rate and concentrate quality are improved. The Leiping Mine in Cangzhou, Hunan Province uses lime to suppress the arsenopyrite, so that the arsenic content of the copper concentrate is reduced from 2% to less than 0.5%.