The method of processing of alloys containing precious and non-ferrous metals

 

(57) Abstract:

The invention relates to the metallurgy of noble metals, in particular to the pyrometallurgical processing of raw materials and concentrates gold and silver. The method of processing of alloys containing precious and non-ferrous metals, is that the original alloy is mixed with a flux containing sodium carbonate, calcium oxide, glass, the mixture is melted, the melt is blown oxygen-containing gas obtained refined noble metal alloy and the slag is then cooled and separated. What's new is that the composition of the slag-forming flux add borax, and as glass is used silicate glass. The method allows to increase the efficiency of the process by reducing the residual content of gold and silver in the slag and improve the content of oxides of non-ferrous metals. 3 table.

The invention relates to the field of metallurgy of noble metals (BM), in particular to the pyrometallurgical processing of raw materials and concentrates gold and silver.

A large group of gold-silver raw materials and concentrates - zinc cementation precipitation, cathodic precipitation of secondary raw materials and industrial products refining processed with use the cerned largely depends on the composition of the source material. The total content of gold and silver alloys are an average of 30-70%, the rest - non-ferrous metals. To improve the content of precious metals alloys before hydrometallurgical processing purge oxidizing gas in the melt.

A method of refining gold-silver alloys by melt processing of gaseous chlorine /1/. Non-ferrous metals by chlorination become horidomecho and partly in chloride slag. The disadvantages are the counterpart of the high cost associated with the use of chlorine and subsequent rework chloride slag and chloridebased containing silver.

A method of refining gold-silver alloys, which is taken as a prototype, as the closest to the claimed technical solution /2/.

According to the method, the alloy containing precious and non-ferrous metals, mixed with a flux comprising sodium carbonate, calcium oxide, glass, a mixture of melt and melt blown oxygen-containing gas. The condensed products of the process - enriched target alloy of noble metals and refining slag then share.

The disadvantages of this method are the low step is the first gold-silver alloy and a high content of noble metal in the refining slag. The reason for this drawback is high enough for the conditions of the implementation process, the melting temperature induced refining slag.

The task, which is aimed by the invention, is to increase the efficiency of processing of gold alloys oxidative refining by reducing the residual content of gold and silver refining slag and improve the content in these slags oxides of non-ferrous metals.

The problem is solved at the expense of achieving a technical result, which is to improve the selectivity of noble metals from non-ferrous, by lowering the melting temperature induced refining slag.

This technical result is achieved by the fact that in the known method of processing of alloys containing precious and non-ferrous metals, including mixing the original alloy with a flux containing sodium carbonate, calcium oxide, glass, melting the mixture and melt blowing oxygen-containing gas according to the invention the flux further comprises borax, as a glass - silicate glass in the following ratio, wt.%:

Borax - 50-60

Oxide, calc the m ratio of the original alloy and flux 1:(1-3).

The difference of the proposed technical solutions from the prototype is the composition of the flux and the refinement of its consumption per unit rafinirovannogo alloy BM.

In the present method used flux allows to obtain non-corrosive slag with a melting point not higher than 1000oC under oxidative refining of gold-silver alloys effectively dissolve in the slag oxides of non-ferrous metals and reduce their residual content of noble metals.

The purpose of the flux components the following. Borax (sodium tetraborates Na2B4O710H2O) is used as the fusible formed the basis of neutral slag having a high extracting ability to oxide complexes of non-ferrous metals. Calcium oxide is used as a component of the flux, which increases the interfacial surface tension at the boundary of the slag - metal, contributing to the coalescence of drops of gold-silver alloy and release them from the slag phase. Silica glass is used as the acidic component of the flux with the aim of linking sustainable silicate complexes of the type [nMe'O mSiO2] oxides of zinc, lead, iron, manifesting predominantly alkaline properties. Sodium carbonate as s is Ter with the formation of low-melting compounds of the type NanMe"Om. The specific composition of the flux is taken on the basis of rafinirovannogo alloy based on the formation of neutral slag.

The flow of flux in the present method is determined by the content of non-ferrous metals in the original alloy and the optimum content of these elements in refining slags. Research has shown that the content of these impurities in refining slags above 25-30% there is a marked dissociation of some oxides of non-ferrous metals or their evaporation and the transition into the gas phase. Experiments have shown that when the content of impurities in the original alloys on the level of 30-70% of the necessary and sufficient flux for maximum extraction of their oxides in a stable slag system is 1-3 mass parts per 1 mass part rafinirovannogo alloy.

The optimal duration of the process of oxidative refining depends on many factors - composition and mass rafinirovannogo alloy, the composition and flow rate of oxygen-containing gas, the device unit, in which the process is conducted. Visually, the process flow can be estimated by the color and physical properties of refined alloy. In particular, the acquisition of resistant alloy sollava and completion of the refining process.

Components of the flux is borax, calcium oxide, silica glass (and/or sodium carbonate) are taken in the approximate ratio of 6:1:3, respectively.

According to experimental data the decrease in the content of borax and calcium oxide in the flux leads to an increase in the content of gold and silver refining slag due to its higher melting temperature and to decrease the amount of interfacial surface tension. The excess of the total content of borax and calcium oxide above 70% leads to a decrease in the efficiency of slagging impurities of non-ferrous metals.

Comparative analysis of the proposed method with the prototype shows that the inventive method differs from the known composition of the flux and its consumption per unit rafinirovannogo alloy. Thus, the proposed solution meets the criterion of "novelty".

To prove compliance of the claimed invention, the criterion of "inventive step" was compared with other technical solutions known from the sources included in the prior art.

The inventive method of processing of alloys containing precious and non-ferrous metals, meets the requirement of "inventive step" as obespechivala, what is not obvious from the prior art.

Examples of using the proposed method

For experimental verification of the proposed method used the gold-silver alloys whose composition is given in table 1.

Experiments for the refining of gold-silver alloys was carried out according to the following procedure. A portion of the alloy BM a mass of 100.0 g was loaded into a corundum crucible. Then the crucible was covered a portion of a flux consisting of a mixture of powders of borax, calcium oxide, silicate glass and/or sodium carbonate. The crucible with the material was placed in an electric crucible furnace with silicafume heaters and kept at a temperature of 1150-1200oC for 10 minutes. Then the melt was blown air with a constant flow using introduced into the molten corundum tube connected to the system dry compressed air. The purge was carried out for 30 minutes. After purging the melt defended for 10 minutes and poured into the cast iron mold. Chilled foods - refined gold-silver alloy and slag were separated, weighed and analyzed for the constituents of the assay and chemical analysis method.

Data on the composition of mixtures of ropinirol is ESA are shown in table 2, examples 1-5. The data and calculations show that using the proposed method, examples 1-3, allows to enrich the alloys according to the content of gold and silver, on average, 1.4-2.7 times with extraction into refined alloy 99,917-99,985% gold and 99,793-99,951% silver. In refining slag goes 68,3-85,6% copper and up to 97,6% electronegative non-ferrous metals.

The use of a flux above or below the proposed limit on the composition and flow rate (examples 4, 5) reduce the degree of selection of gold and silver from base metals, reduces the extraction of BM in the target alloy or accompanied by excess flux for refining.

An example of using the prototype method

To compare the performance of the proposed method and the method of the prototype spent experience oxidative refining of the alloy "B" in accordance with the prototype method. As a flux used a mixture of powders of calcium oxide, silicate glass, and sodium carbonate. The number of components of the flux was taken from the calculation that smelting get about the same amount of refining slag, as in the example No. 2.

The results of the experiment - out products, content and distribution of the elements presented in table 2, p is osobov presented in table 3.

The data of table 3 show that using the proposed method of processing of alloys containing precious and non-ferrous metals, allows in General to increase the selection of gold and silver from base metals by increasing the content of precious metals in the target gold-silver alloy and increase the degree of slagging impurities and reduce the content of noble metals refining slags.

For the proof of the criterion of "industrial application" should indicate that the inventive method will be tested on a number of gold mining companies in Russia in 2000-2001.

Sources of information

1. Malinetskii I. N., Chugaev L. C., Borbat C. F. and other metals precious metals. - M.: Metallurgy, 1987. - S. 312 - 315.

2. Plaksin, I. N. Metallurgy of noble metals.- M: Metallurgizdat, 1958. - S. 330 prototype.

The method of processing of alloys containing precious and non-ferrous metals, including mixing the original alloy with a flux containing sodium carbonate, calcium oxide, glass, melting the mixture, the melt blowing oxygen-containing gas, wherein the flux further comprises borax, as a glass - silicate glass is eat sodium - Else

moreover, the mixing is carried out at a mass ratio of the original alloy and flux 1 : (1 - 3).

 

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FIELD: noble metal metallurgy, in particular method for gold content determination in natural solid organic materials such as divot, state coal, brown coal, and black coal.

SUBSTANCE: claimed method includes sampling the probe of starting material, grinding, mixing with massicot, smelting to form bullion, parting of gold-silver globule, weighting of gold sinterskin. Probe is sampled from starting natural solid organic material. Before smelting mixture is packaged in lead foil, established in full-hot scorifying dish, and padded with borax and table salt.

EFFECT: precise method for gold content determination in natural solid organic materials.

1 tbl, 1 ex

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