Oxide lead ores

The use of barium sulphide as a secondary sulphidizer [4] was examined on oxidized lead ores from Sicily (BaS). The results obtained were encouraging. Sulphidization using Na2S can also be improved with the use of ammonium salts (chloride and sulphate). These reagents are used in cases where the ore contains clay minerals and calcium carbonate, which prevents suphidization due to the production of soluble calcium bicarbonate. The ammonium increases the solubility of calcium carbonate and improves sulphidization. 

Silver oxide lead ores have much different flotation processing characteristics. Although this ore responds to sulphidization-xanthate system, silver recovery in the lead concentrate was usually poor and amounted to about 30 40%. Floatability of lead minerals also was not satisfactory. 

ALKANOLAMNES - ALKANOLAMINES FROM OLEFIN OXIDES AND AT ONIA] (Vol 2) -of lead ore pEAD] (Vol 15)... 

Production and Economic Aspects. Thallium is obtained commercially as a by-product in the roasting of zinc, copper, and lead ores. The thallium is collected in the flue dust in the form of oxide or sulfate with other by-product metals, eg, cadmium, indium, germanium, selenium, and tellurium. The thallium content of the flue dust is low and further enrichment steps are required. If the thallium compounds present are soluble, ie, as oxides or sulfates, direct leaching with water or dilute acid separates them from the other insoluble metals. Otherwise, the thallium compound is solubilized with oxidizing roasts, by sulfatization, or by treatment with alkaU. The thallium precipitates from these solutions as thaUium(I) chloride [7791 -12-0]. Electrolysis of the thaUium(I) sulfate [7446-18-6] solution affords thallium metal in high purity (5,6). The sulfate solution must be acidified with sulfuric acid to avoid cathodic separation of zinc and anodic deposition of thaUium(III) oxide [1314-32-5]. The metal deposited on the cathode is removed, kneaded into lumps, and dried. It is then compressed into blocks, melted under hydrogen, and cast into sticks. 

By-Product and Secondary Antimony. Antimony is often found associated with lead ores. The smelting and refining of these ores yield antimony-hearing flue, baghouse, and CottreH dusts, drosses, and slags. These materials may be treated to recover elemental antimony or antimonial lead from which antimony oxide or sodium antimonate may be produced. 

A lead ore, galena, consisting mainly of lead(II) sulfide, is the principal source of lead, lb obtain the lead, the ore is first heated in the air to form lead oxide. 

The principal lead ore is galena, PbS. It is roasted in air, which converts it into PbO, and this oxide is then reduced with coke ... 

As mentioned above, approximately 7% of the total sulfur present in lead ore is emitted as S02. The remainder is captured by the blast furnace slag. The blast furnace slag is composed primarily of iron and silicon oxides, as well as aluminum and calcium oxides. Other metals may also be present in smaller amounts, including antimony, arsenic, beryllium, cadmium, chromium, cobalt, copper, lead, manganese, mercury, molybdenum, silver, and zinc. This blast furnace slag is either recycled back into the process or disposed of in piles on site. About 50 to 60% of the recovery furnace output is slag and residual lead, which are both returned to the blast furnace. The remainder of this dross furnace output is sold to copper smelters for recovery of the copper and other precious metals. 

When galena, a lead ore (composed of lead sulfide) is roasted in a well-ventilated, open furnace, part of the lead is oxidized by air oxygen to lead oxide and the sulfur to sulfur dioxide, which is released into the atmosphere (see Textbox 33) ... 

Dieter MP, Matthews HB, Jeffcoat RA, et al. 1993. Comparison of lead bioavailability in F344 rats fed lead acetate, lead oxide, lead sulfide, or lead ore concentrate from Skagway, Alaska. J Toxicol Environ Health 39 79-93. 

The sulphidization process, which was first successfully applied on a commercial scale on lead carbonate ores, is currently the most popular method used during treatment of oxide copper ores that contain malachite and carbonaceous gangue. The commonly used sulphi-dizers are Na2S 9H20 and NaHS, with xanthate or xanthate ester. 

Flotation of Mixed Lead Zinc Sulphide Oxide and Oxide Lead and Zinc Ores... 

SULPHIDE OXIDE AND OXIDE LEAD ZINC ORES... 

There are a variety of mixed sulphide oxide ores and oxide lead zinc ores, and these ores cannot be classified into any specific group due to the vast differences in geology and mineral compositions. Only limited literature is available on the geological and miner-alogical characteristics of these ores. From a processing point of view, these ores can be classified into the following groups ... 

Mixed sulphide and oxide lead zinc ores... 

Oxide zinc ore with little or no lead present. 

Flotation of the lead oxide minerals is a difficult problem not least because there are no known direct acting collectors. Normally, during oxide lead flotation, a sulphidization method is used with xanthate as a collector. In the majority of cases, the ore is pretreated using a desliming process, especially if the ore contains clay and Fe-hydroxides. Another method includes the preconcentration using heavy liquid. 

During oxide lead flotation, the choice of collector is rather limited to xanthates, which are used in operating plants. Dithiophosphates and mercaptans are used as secondary collectors. This is due to the fact that natural ores contain a variety of floatable gangues, for which the anionic flotation process is not applicable. The use of chelating agents as flotation collectors for oxide lead flotation have been extensively examined [5,6], Oximes/fuel oil... 

Wulfenite and minetizit are mainly associated with oxide lead silver ores. Very little to no research data are available on these two minerals. Most recently, research work was carried out on these minerals using natural ore. It has been demonstrated that wulfenite and minetizit can be recovered using sulphidization and modified xanthate. 

Most recently, a new line of collectors [9] have been studied. These collectors are based on xanthated fatty acid (collectors from the DS series (Xanthate = 60%, Fatty Acid = 20% and Fuel Oil = 20%)) and xanthated mixtures of fatty acid and amine (DAS series (Xanthate = 50%, Fatty Acid = 20%, Amine Oxide = 20% and Fuel Oil = 10%)). These collectors were examined on a number of oxide lead zinc ores from Egypt, South America and Canada. Typical results obtained with the new collectors are presented in Figure 20.3. 

There are only a few operating plants that treat mixed and oxide lead zinc ores. Most of these plants are located in Sicily, Ireland, Morocco, Egypt and Canada, but there are operating plants found in the USA, Mexico and Argentina. In the past 20 years, extensive research has been conducted on a variety of oxide lead zinc ores with the objective of developing a commercial treatment process. Some of these processes are commercially applied in several operations. 

Practices in the Beneficiation of Mixed and Oxide Lead Zinc Ores... 

These ore types are abundant in Northern Canada and Mexico. Extensive research work was carried out on these ores with the objective of developing a treatment process for commercial application. One of the major tasks in the development testwork was to use a non-cyanide flotation method in the sulphide flotation. Typical reagent schemes used in beneficiation of the mixed lead zinc oxide sulphide ores are shown in Table 20.5. 

---