Chrysocolla

The present description pertaining to copper refers to solvent extraction of copper at the Bluebird Mine, Miami. When the plant became operational in the first quarter of 1968 it used L1X 64, but L1X 64N was introduced in to its operation from late 1968. The ore consists of the oxidized minerals, chrysocolla and lesser amounts of azurite and malachite. A heap leaching process is adopted for this copper resource. Heap-leached copper solution is subjected to solvent extraction operation, the extractant being a solution of 7-8% L1X 64N incorporated in kerosene diluent. The extraction process flowsheet is shown in Figure 5.20. The extraction equilibrium diagram portrayed in Figure 5.21 (A) shows the condi-... 

A variety of mineral ores, mostly copper minerals such as malachite and chrysocolla, were probably the most used green pigments in the past. Various green minerals derived from metals other than copper, such as green earth (see below) were used in confined regions. 

Copper oxide mixed ore - Type 1. The main copper minerals found in these ores include malachite, pseudo-malachite, chrysocolla and some tenorite. These ores also may contain mainly siliceous gangue minerals, including spherocobaltite as the main cobalt minerals. The carbonaceous types also contain an appreciable amount of clay slime minerals. 

Mixed copper sulphide oxide ores. These contain varieties of both sulphide and oxide minerals, and are the most complex copper-bearing ores from a beneficiation point of view. The major copper minerals present in this ore type include bomite, chalcocite, covellite, malachite, cuprite and chrysocolla. In some cases, significant amounts of cobalt minerals are also present in this ore. 

Chrysocolla (CuOxSi02 Cu= 10-36%, SG — 2-2.4) is the most studied mineral of all the oxide minerals. Extensive laboratory studies have been conducted by numerous researchers [9-11]. The laboratory research work indicates that chrysocolla can be floated using the sulphidization method, as shown in Figure 19.4, or by hydroxamate collectors. However, none of these processes have been applied at an industrial scale. 

In a number of operations, chrysocolla has been recovered using a hydrometallurgical technique. 

Figure 19.4 Effect of Na2S concentration on the flotation of chrysocolla.

Gonzales, G., The Recovery of Chrysocolla with Different Long Chain Surface-active Agents as Flotation Collectors, Journal of Applied Chemistry Biotechnology, Vol. 16, No. 28, pp. 31-38, 1978. 

Copper is the 26th most abundant element on Earth, but it is rare to find pure metallic deposits. It is found in many different types of mineral ores, many of which are close to the surface and easy to extract. It is found in two types of ores (1) sulfide ores, such as covellite, chalcopyrite, bornite, chalcocite, and enargite and (2) oxidized ores, such as tenorite, malachite, azurite, cuprite, chrysocolla, and brochanite. 

Heap (dump) acid leaching of copper sulfide ores is possible with the aid of microbial oxidation. Not all copper minerals are sulfidic, however— malachite, azurite, and chrysocolla are basic copper carbonates—and sulfuric acid heap leaching of low-grade copper carbonate ores can give solutions from which the Cu2+ ion can be separated by solvent extraction (Section 17.3) and copper metal obtained by electrowinning. 

Cyanos was a blue gem of much value, and it has been identified as the stone called lapis lazuli, though Theophrastus also refers to another kind of cyanos, which has in it chrysocolla. This doubtless refers to our azurite, a hydrated copper carbonate, used by the ancients as a blue pigment, and known to the Latins as armenus, so named after the locality, Armenia, from which it was largely obtained. 

Chrysocolla, Vitruvius says, is a green pigment brought from Macedonia and dug up in the vicinity of copper mines. As with Theophrastus, this is doubtless our malachite. Vitruvius states that those who cannot use chrysocolla on account of its cost employ a blue color (coeruleum) mixed with the plant called lutum, and obtain a very vivid green. Pliny also states this fact, but adds that it gives a very inferior color. 

This word chrysocolla of the ancients, which denotes malachite, was not confined to that mineral, as appears particularly from the extended description of Pliny. He mentions the substance dug from the mines in proximity to gold, but he also states that it is a liquid found in the shafts of mines—a slime hardened by the cold of winter till it haB the hardness of pumice. The most valued is from copper mines, the next best from silver mines, and that from the gold mines is inferior. In the mines also an artificial chrysocolla is made by allowing water to percolate into the veins during the winter and spring, and evaporating these in July and August. 

Pliny also states that coeruleum is a kind of sand. It seems probable that besides the blue glass, native blue minerals were also used, as for instance the cyanos of Theophrastus and of Pliny, probably lapis lazuli, and azur-ite, the other kind of cyanos referred to by Theophrastus as containing chrysocolla. 

Copper, burned copper and flowers of copper with vinegar also yield ios. It may be assumed that as between verdigris (carbonate) and acetate of copper, no distinction was made ios of the Greeks and chrysocolla of the Latin writers cover both. Also the method of obtaining ios by rubbing copper and vinegar in a copper mortar is given by Dioscorides as previously by Theophrastus. When Theophrastus speaks of chrysocolla, he refers to malachite or to some other copper salts or mixtures of salts, vitriols, etc. 

Green pigments were chrysocolla, malachite, or other basic carbonates of copper and appianum, a green earth or chalk said to be a cheap and inferior color. 

It will be recalled that the term chrysocolla was applied also to malachite, verdigris and copper acetate, all of these being used for soldering gold. 

---