Research on Experimental and Application for the High Efficient Enrichment of the Low-grade Precious Metal Materials

On the basis of reviewing the progress in the high efficient enrichment from secondary resources of low grade precious metals at home and abroad, a process route of the high efficient enrichment precious metals from secondary resources of low-grade metals by adding iron oxide as the trapping agent, reducing agent, additive, mixing uniformly and grinding, pelletizing, reduction, grinding and separation, and selectively acid leaching iron has been put forward in this paper. The experiments of reduction, grinding and separation, and selectively acid leaching iron were carried out mainly. Under the decided experiment parameters and conditions, iron generated during the reduction can trap precious metals during reduction, high active alloy powders were obtained from the reduced products by grinding and separation, the concentration of precious metals was obtained by acid leaching high active alloy powders. The better enrichment effect was obtained by adopting the technical route of processing. Other low grade noble metal materials and enrichment ratio of precious metals from the materials to acid products was high through acid leaching. This process has the advantages of simple process, environmental-friendly, strong adaptability of raw materials, high concentration ratio, which was regarded as a kind of the general efficient enrichment technology of low grade precious metal materials.

Precious Metals Identification in Computer Motherboards

Elements can be classified into metals,nonmetals,or metalloids based on their chemical and physical properties.Precious metals are rare and expensive.There are ten known precious metals,three of which are of interest to investors,silver,gold,and platinum.The goal is to find physical methods to identify the presence of precious metals,silver,and gold in the metal components of the computer motherboard,and to confirm its presence by chemical methods for its use and its selling to the jewelry industry after it is physically separated from the computer motherboards.Physical and chemical tests were identified.Physical tests include inscription test,magnet test and specific gravity test for both silver and gold metal pieces and chemical tests include bleach test,nitric acid test,test karat solution kit,and jewelry test kits.

General approach for atomically dispersed precious metal catalysts toward hydrogen reaction

As a carbon-free energy carrier,hydrogen has become the pivot for future clean energy,while efficient hydrogen production and combustion still require precious metal-based catalysts.Single-atom catalysts(SACs)with high atomic utilization open up a desirable perspective for the scale applications of precious metals,but the general and facile preparation of various precious metal-based SACs remains challenging.Herein,a general movable printing method has been developed to synthesize various precious metal-based SACs,such as Pd,Pt,Rh,Ir,and Ru,and the features of highly dispersed single atoms with nitrogen coordination have been identified by comprehensive characterizations.More importantly,the synthesized Pt-and Ru-based SACs exhibit much higher activities than their corresponding nanoparticle counterparts for hydrogen oxidation reaction and hydrogen evolution reaction(HER).In addition,the Pd-based SAC delivers an excellent activity for photocatalytic hydrogen evolution.Especially for the superior mass activity of Ru-based SACs toward HER,density functional theory calculations confirmed that the adsorption of the hydrogen atom has a significant effect on the spin state and electronic structure of the catalysts.

Overview of Precious Metal Content Analysis Methods in Automotive Catalytic Converter

With the increasing awareness of environmental protection, people’s concern of pollution issues arising. Vehicles, as the most important means of transportation, its exhaust emission has received considerable attention. The catalytic converter is able to purify harmful substances in exhaust gas. The absolute content of precious metals in the catalytic converter dominates the exhaust gas purification effect. Accurate detection of precious metal content is of great significance for controlling the cost of catalysts, ensuring catalytic performance and recovering precious metals from spent catalysts. We herein summarized several instruments for precious metals content exploration, such as X-ray fluorescence spectrometer (XRF), atomic absorption spectrometer (AAS), inductively coupled plasma emission spectrometer (ICP) and spectrophotometer. In this thesis, the feasibility of using various devices for characterizing precious metal content in catalytic converters is analyzed and their strengths or weaknesses are elaborated.

Progress in Microwave Technology Applied to the Recovery of Precious Metals from the Secondary Resources

The recovery of precious metals from the secondary resources by microwave technology has emerged in recent years. Microwave technology as a new method for the recovery of precious metals has shown significant advantages against the conventional recovery procedures. This paper presents a review of the advances in microwave technology applied to the recovery of precious metals from the secondary resources. Many different applications are considered, including microwave-assisted leaching, microwave augmented ashing and microwave pyrolysis. In general, microwave enhanced recovery of precious metals from secondary resources.

New Technology for High Efficient Recovery of Precious Metals Six-component Alloy Wastes

Aimed at high content of valuable metals, complicated composition, difficult to separation of precious metals six component alloy wastes, the present paper proposed a new technology of high efficient separation and purification. Using fragmentation technology realizes fast dissolution of palladium, silver, copper and zinc in the wastes, and high efficient and complete separation of them from gold and platinum; using evaporation thermal decomposition technology of mixed solution produced by nitric acid dissolving palladium, silver, copper and zinc, complete and high efficient separation of silver from palladium was realized; by control of solution acidity, using hydrazine reduction method, high efficient and complete separation of gold from platinum was realized. Using this new technology, the recovery rates of palladium and silver are above 99%, and gold and platinum above 98%, the grade of pure metals are above 99.95%.

Kunming Institute of Precious Metals

Situated in Kunming,Yunnan Province,the institute is a scientific research organiza-tion with a history of fifty years.It is nowaffiliated with the China National NonferrousMetals Industry Corporation.At the beginning of the nineteen sixties,the institute commenced research workin the field of precious metals.It has sincethen developed and extended greatly,andits activities now cover various fields ofprecious metals science and technology,including the comprehensive utilization

Russia's Precious Metals Market: Condition and Prospects

The region of existence of phases in equilibrium with the solid solution based on palladium. Presented to analyze the current situation in the market of precious metals in Russia. Provides information about the production and processing of precious metals. Prospects for the most likely path of development of the Russian market of precious metals.

A Two-step Sequential Extraction for Analyzing Hardly Accessible Precious Metals in Sulfide Ore-bearing Sedimentary Rocks

The work concentrates on extraction of precious metals (Au, Ag, Pd, Pt) and As, Sb, Cu, Pb, Zn, and Fe which are bound to sulfide-ore minerals in sedimentary rocks, using a two-step sequential extraction experiment with two chemical reagents (hydrogen peroxide and aqua regia) on three rock specimens from the black shale formation in Bakyrchik gold-sulfide deposit in North-East Kazakhstan. The experiment allows to determine the speciation of hardly accessible precious metals and to identify the most productive ore-forming stage from the three identified ones. Analytical methods are used for determining polysulfide mineral textures (optical microscopy), mineralogical (XRPD) and chemical compositions (XRF), and for measuring extracted metals concentrations (ICP-OES) in experimental procedures. The analytical results show that the first stage is more productive in gold (total extraction 2.8 ppm) than others and the second stage is more productive in Ag (total 1.6 ppm) and Pd (total 0.01 ppm), while the last stage is more productive in Pt (0.019 ppm) in the deposit.

On the Dynamics of Informatization of the Russian Market of Precious Metals

In June 2012,the UN conference on sustainable development "Rio+20" summarized the work of the world community in this direction for last 20 years and outlined the tasks for the future.The UN website contains enough information to estimate the importance of global problems and "green economy," taking into account a very complicated state of the global and Russian markets which are balancing on the verge of crisis.Unfortunately,the website does not contain the materials of the 6th civilization forum "Long-Term Strategy for Sustainable Development on the Basis of Partnership of Civilizations:Concepts,Strategy,Programs and Projects" within the bounds of "Rio+20" which has considered the problems of a dialogue and partnership in conditions of extensive globalization.These problems are covered in the Partnership of Civilizations Journal which is issued in the Russian,English and Arabian languages,including its Internet version.The International Informatization Academy (it has the general consultative status at the Economic and Social Council of the UN) and its 20-year activity in the sphere of informatization of the world and Russia on the way to the partnership of civilizations,are presented there[1].

Discussion of an Enrichment Mechanism of Precious Metals by Base Metals and Mattes in Pyro-metallurgical Processes

The enrichment mechanisms of precious metals by base metals or their mattes in pyro-metallurgical processes are discussed at the atomic level in this paper.The reasons brought forward for a trace amount of precious metals to be trapped into base metals or mattes are that the melted slag phases possess different chemical structures and properties from that of the melted base metal or matte phases.As for the melted slag phase,its formation is thought to depend on the covalent bonds and the ionic bonds between Si,O atoms and Ca2+,Mg2+,Fe2+ ions to tie up each other.Because the bridging electrons in the slag phase are all thought as the localized electrons,the precious metal atoms are not stable among them.However,as for the metal phase,its formation is thought depend on the metal bonds to bind up the metal atoms.Because the electrons in the metal phases can move freely among the atoms,the precious metal atoms that enter the metal phase can cause the system's free energy to decrease.For the melted mattes phase,because it has high electrical conductivities(between 103～104 s·cm-1) at higher temperatures,and its temperature coefficients presents the negative values,its conductance mechanism belongs with the electronic conduction.The property of the mattes is in fact similar to that of the metal at their melted state,so the precious metal atoms will enter the matte phase instead of the slag phase in a matte-smelting process.

Deselenization and detellurization of precious-metal ore concentrates by swelling oxidizing roasting and successive alkaline leaching

A new technique of swelling oxidizing roasting and alkaline leaching was proposed for deselenization and detellurization of pre- cious-metal ore concentrates. Alkali-metal and alkaline-earth-metal chlorides and carbonates were preliminarily selected as swelling agents. The roasting removal rate and alkaline leaching rate of selenium and tellurium were investigated, and NaCl was selected as an appropriate swelling agent. Furthermore, the effects of various factors on the selenium gasification rate and leaching rate of selenium and tellurium were investigated. The results show that the selenium gasification rate reaches 88.41% after swelling oxidizing roasting for 2 h at 510~C using an NaC1 dosage coefficient of 100 and a sulfuric acid dosage coefficient of 1.3; the amorphous elemental tellurium is completely transformed into TeO2. The roasted product is subjected to alkaline leaching using a 100 g/L NaOH solution, which results in a selenium leaching rate of 10.51%, a total selenium removal rate of 98.92%, and a tellurium leaching rate of 97.64%. In the alkaline leaching residue, the contents of selenium, tellurium, gold, platinum, and palladium are 0.7825%, 5.492%, 8.333%, 0.2587%, and 1.113%, respectively; the precious metals are enriched approximately sixfold.

Reductive recovery of manganese from low-grade manganese dioxide ore using toxic nitrocellulose acid wastewater as reductant

The hydrometallurgical strategy of extracting Mn from low-grade Mn ores has attracted attention for the production of electrolytic manganese metal(EMM). In this work, the reductive dissolution of low-grade Mn O2 ores using toxic nitrocellulose acidic wastewater(NAW) as a reductant was investigated for the first time. Under the optimized conditions of an Mn O2 ore dosage of 100 g·L-1, an ore particle size of-200 mesh, concentrated H2 SO4-to-NAW volume ratio of 0.12, reaction temperature of 90°C, stirring speed at 160 r·min-1, and a contact time of 120 min, the reductive leaching efficiency of Mn and the total organic carbon(TOC) removal efficiency of NAW reached 97.4% and 98.5%, respectively. The residual TOC of 31.6 mg·L-1 did not adversely affect the preparation of EMM. The current process offers a feasible route for the concurrent realization of the reductive leaching of Mn and the treatment of toxic wastewater via a simple one-step process.

Technology Development and Production of Certain Chemical Platinum Metals Compounds at JSC ＂Krastsvetmet＂

In recent years JSC "Krastsvetmet" has successfully developed the production of chemically pure compounds of precious metals.Currently methods have been developed and facilities have been provided for industrial production of the following platinum metals compounds:Rhodium(Ⅲ) chloride hydrate,rhodium(Ⅲ) chloride solution,rhodium(Ⅲ) nitrate solution,rhodium(Ⅲ) iodide,rhodium(Ⅲ) sulfate,hydrated rhodium(Ⅲ) oxide,ammonium hexachlororodiate,rhodium(Ⅲ) phosphate solution,rhodium electrolytes;Iridium(Ⅳ) chloride hydrate,iridium(Ⅲ) chloride hydrate,ammonium hexachloroiridate(Ⅳ),hexa chloriridium acid solution,hexachloriridium crystalline acid;Ruthenium(Ⅲ) chloride hydrate,ruthenium(Ⅳ) hydroxide chloride,ruthenium(Ⅳ) hydroxide chloride solution,ammonium hexachlororuthenate,ruthenium(Ⅲ) chloride solution,potassium,diaquaoctachloronitrido diruthenate.The quality of the production meets the requirements of Russian and foreign consumers.

Simultaneous Removal of Soot and NO_x over Precious Metal Catalysts O_2-Rich Atmospheres and in the Presence of H_2O and SO_2

The activities of ZrO_2-supported precious metal catalysts for simultaneous removal of soot and NO_x in the presence of rich O_2and H_2O as well as SO_2 have been studied by keeping loose contact between catalyst and soot.The results show that only Ru,Ir and Rh have catalytic activity for simultaneous removal of soot and NO_x and the order of catalytic activity is Ru > Ir > Rh.Pt has the catalytic activity only for the removal of soot,and Ag,Pd,and Au have hardly any catalytic activities for the removal of soot and NO_x.The relationships between catalytic activity of precious metal catalysts and various reaction conditions were discussed.

Can news-based economic sentiment predict bubbles in precious metal markets?

This study examines the role of market sentiment in predicting the price bubbles of four strategic metal commodities(gold,silver,palladium,and platinum)from January 1985 to August 2020.It is the first to investigate this topic using sentiment indices,including news-based economic and consumer-based sentiments developed using different methods.We observed the role of sentiment as a reliable indicator of future bubbles for some metal commodities and found that bubbles were regularly concomi-tant with bearish sentiments for gold and platinum.Moreover,gold and palladium were the only commodities that experienced a bubble during the COVID-19 pandemic.Overall,our findings suggest inclusion of sentiment to the model that predicts the price bubbles of precious metals.

Manufacture of Precious Metal Products： Advancement and Prospect

A survey about OJSC "SIC Supermetal'" as a processor of secondary precious metal raw materials and a manufacturer of precious metal products for technical purposes,has been presented.Brief information has been given about the basic technologies and materials used in production,including dispersion strengthened materials on the basis of platinum alloys and laminar composites.

Optimization of Precious Metal Recovery from Waste Electrical and Electronic Equipment Boards

Recovering noble metals from Waste Electrical Electronic Equipment (WEEE) will provide an additional income within the disposal process of end-of-life electronic devices. Generally, the recycling process starts with the manual disman-tling of different devices and with sorting of the subdivided products into useful and hazardous materials. A sample of about 21 tonnes of WEEE was dismantled in 14 days to remove Printed Circuit Boards (PCBs) that were about 5% weight of the whole sample. Computer PCBs proved to contain the 96% of all the gold present in all types of PCBs of the sample. Computer PCBs were manually dismantled to obtain the easy-to-remove components of the board, namely, the integrated circuits and the processors, which were about 13% weight of the board and 0.1% weight of the whole WEEE sample and contained about 91% of the gold present in the whole board with an average concentration of 2400

Magnetic Iron Oxide Nanoparticles Modified with Moringa Seed Proteins for Recovery of Precious Metal Ions

Precious metals are highly demanded economic value metals that require to be recovered from industrial wastes and electronic used products (e-waste). They are such as gold (Au) as well as Platinum Group Metals (PGMs) for instance palladium (Pd) and platinum (Pt). The study was conducted to test the magnetic iron oxide nanoparticles modified with Moringa oleifera seed proteins as adsorbent for recovery of Au(III), Pd(II) and Pt(IV) from aqueous solutions. Different functional groups responsible for adsorption, morphology, thermal stability, and surface charges of the nanoparticles were characterized with FTIR, SEM, TGA and Zeta potential respectively. Batch adsorption method was used, and precious metal ions percentage recovery was measured using ICP-OES. The effects of pH, initial adsorbate concentration, adsorption agitation time and adsorbent dosage were studied at room temperature of 25°C. Au(III) yielded a maximal recovery of 99.8%, followed by Pt(IV) with 87.7%, then Pd(II) with 72.7% at a pH 2.5, 10 mg/L initial adsorbate concentration, 120 minutes agitation time and 0.065 g adsorbent dosage. These results suggested that modified iron oxide nanoparticles were effective in selective recovery of the precious metal ions.

Comparative Study of Gold Concentration by Elutriation from Different Precious Metal Bearing Ores

Conventional methods for precious metals gravimetric concentration involve equipment such as shaking tables, centrifuging concentrators, jigs, trommels, or a combination of those. A less commonly used technique is elutriation, which represents an efficient, safe and low-cost method of separation. The goal of the present investigation was to make a comparative study of gold concentration by elutriation from different precious metal bearing ores: an oxide ore, a mineral consisting of a sulfide matrix, a mineral in which the precious metals are free and disseminated and a slimy and clayey black sand material. The best recoveries of precious metals by elutriation were attained for the free disseminated ore and for the black sands, obtaining gold recoveries of 70% and 96% respectively, with appreciable ratios of concentration as well.