GB2150549A

GB2150549A - Process for the separate recovery of metal chlorides from complex ores etc

Info

Publication number: GB2150549A
Application number: GB08429902A
Authority: GB
Inventors: Pavel Hurt
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-12-01
Filing date: 1984-11-27
Publication date: 1985-07-03
Also published as: DE3343541C2; DE3343541A1; GB2150549B; GB8429902D0

Abstract

The recovery of chlorides of metals and semimetals from oxidic and/or sulfidic ores, or ore concentrates, coals, petroleum, oil shale or sand, sand and inorganic residues thereof by decomposing them with hydrochloric acid, filtering the non-dissolved residue and heating the filtrate to first evaporate the water and then sequentially recover, in accordance with the respective boiling points, the pure chlorides by fractional distillation or sublimation. <IMAGE>

Description

SPECIFICATION Process for the separate recovery of metal chlorides from complex ores etc.

The invention concerns a process for the separate recovery of metal chlorides from complex ores, ore concentrates, coals, petroleum, oil shales or sands and the inorganic residues thereof.

The decomposition of oxidic ores or ore concentrates obtained after enriching by mechanical concentration e.g. in settling machines or by flotation is effected, in general, depending on the type of ore, in accordance with melt-metallurgical or wet metallurigcal processes. Sulfidic ores, in particular copper ores are frequently roasted first in order to reduce the sulphur content which in many cases interferes with the subsequent process measures for reducing the ore to metal.

The smelting of various ores, especially after separation and recovery of the main metal, entails residue ores and concentrates that contain further valuable metals which are further processed to recover said valuable metals. Said residues however are dumped as waste at present if the content of valuable metals is a minor one or said metals are present only in such compounds that would make their recovery unprofitable.

Coals, in particular slag and ash, i.e. fly ash and non-fused inorganic residues from the firing of coal and of oil products, contain valuable metals in small amounts, such as Be, V, Ga, Ge, U and the like, the recovery of which can be of economic interest.

The present invention affords the possibility to process such complex ores or ore concentrates and inorganic residues of the firing of coal, coal products, petroleum, oil shales and sands and the like still in a profitable manner.

The invention relates to a process for the treatment of the above mentioned raw materials to recover their respective metal chlorides. According to the process of the invention, it is possible to process raw material that otherwise, due to the contents of e.g. arsenic, antimony, mercury of bismuth, and beryllium, vanadium, uranium, gallium or germanium, is regarded as not worthwhile to be smelted. The starting materials may be oxidic, silicatic or sulfidic.

According to the process of the invention the optionally roasted or partly roasted ore or ore concentrate is decomposed by hydrochloric acid. For the decomposition of the raw material it is not absolutely necessary to use concentrated hydrochloric acid. It can be worked also with a relatively diluted hydrochloric acid. The acid concentration depends on the particular hydrochloric acid being available, the decomposability of the ores, or the materials of which the plant for the acid decomposition consists.

After a reaction period with the hydrochloric acid that can readily be determined for the material to be decomposed, optionally under agitation at elevated temperatures, the hydrochloric acid solution of the metal chlorides is separated by filtering from the insoluble, essentially silicate residue. If the starting material contained silver, the silver content is present in the residue separated by filtration as insoluble silver chloride. From said residue it can be recovered in the usual manner, e.g. by separation with the aid of complex forming agents for silver, such as a solution of ammonia, thiosulfate of alkali cyanide.

If the starting material contains in addition sulphur, e.g. when a sulfidic ore or ore concentrate having not been roasted or having been partly roasted only, is concerned, hydrogen sulfide is formed from the metal sulfides during the acid decomposition and hence it is necessary to work in a closed decomposition plant in keeping with the safety regulations prescribed for hydrogen sulfide because of its toxicity. The hydrogen sulfide can then be separated from exhaust air in the usual manner, e.g. by oxidizing it. to SO2, or by washing the gas with iron salt solutions or the like.

The filtrate containing the chlorides of the metals and semimetals is according to the process of the invention then supplied to a fractioning plant, in which the chloride solution is heated to first evaporate the water contained and to then recover from the melt of the metal chlorides the individual chlorides by fractionated distillation or sublimation.

The desired chloride with high purity is obtained by repeated fractionations. Said chloride may be used as such or the respective metal or semimetal may be recovered therefrom.

The advantages of the process according to the invention reside in that it is possible in a simple manner with said process to process also lean ores or ores that are so complex that they previously could not be processed in a profitable manner, or in which, because of the formation of toxic vapors or the like, specific safety regulations had to be observed. Besides, the individual chlorides are obtained in the desired purity without it being necessary to have therefor complex plants.

The process of the invention is explained in more detail with the aid of the following example.

EXAMPLE As starting material a fine ore concentrate is used whose analysis provided the following contents: 24% Cu, 15% Sb, 25% Fe, 23% S, 0.9% Hg, 1% As, 0.3% Ag, 2ppm Au. The remainder consisted of silicates and (earth) alkalis.

1,000 kg of the above ore concentrate were decomposed in a closed vessel lined with lead, under agitation, with 500 1. of a 10% hydrochloric acid, at a temperature of from 70"C for a period of about 2 h. After completion of the decomposition, the decomposition mass was filtered and the filtrate was supplied into a fractioning column of titanium in which the stepwise distillation was carried out.

After evaporating the water, sequentially distilled off are arsenic chloride at about 130"C, antimony chloride at about 223"C, mercury chloride at about 302"C, iron chloride at about 316"C and finally bismuth chloride at about 447 C. At about 500"C the fractional distillation is interrupted and pure copper chloride is obtained as fractionation residue.

If the purity of the one of the other fraction is not yet fully satisfactory due to an entraining of a volatile, higher-boiling chloride, it is possible to repeat said portion of the fractioning as often as necessary.

From the chlorides recovered in such purity it is easy - unless these chlorides are to be used directly - to recover the metals or semimetals in a manner known per se.

Claims

1. A process for the separate recovery of chlorides of the metals and semimetals from a raw material selected from complex ores or ore concentrates, coal, petroleum, oil shale or sand, sand and residues thereof wherein the raw material is decomposed by hydrochloric acid, optionally at an elevated temperature, the decomposed mass is filtered, the water of the filtrate is evaporated, the chlorides of the metals and semimetals are fractionally distilled up to a temperature of about 5002C, and, in the case of copper-containing raw materials, copper chloride is then recovered from the distillation residue.

2. The process as defined in claim 1 wherein, in the case of a silver-containing raw material, the silver chloride contained in the acid decomposition residue is dissolved by means of a solution of a complex forming agent for silver and the silver is recovered from the solution in a manner known per se.

3. The process as defined in claim 1 or claim 2 wherein a concentrate of a copper iron ore is used as raw material.

4. The process as defined in any of claims 1 to 3 wherein at least partly roasted ore or concentrates is used.

5. A process according to claim 1 and substantially as hereinbefore described in the Example.