However, the conventional gold recovery process is cyanidation, due to the recent environmental laws; researchers are looking for alternative methods for the recovery of gold. Furthermore, the copper anode slime is one of the most important secondary sources of gold (about 1200 ppm). So, the main objective of the current work is gold separation from copper anode slime as a rich secondary source of gold by determining the mechanism of the reaction between thiourea (TU) and Hydrogen peroxide (H2O2) in the thiourea leaching of gold. Thiourea can form cationic complex with gold in gold extraction process from copper anode slime. Thiourea consumption levels were also examined during the leaching operations for different leaching parameters, i.e. solution volume, concentration ratio of thiourea/H2O2, pH, leaching time and Agitation rate. Ammonia was added to the gold containing solution, and consequently, gold was precipitated in the metallic form. X-Ray pattern confirms formation of metallic gold.

Is gold a hedge or diversifier, defined as an asset that is related with stocks on average, or is it a safe haven, defined as an asset that has a special relationship with stock market in the times of market crash? We study the relationship between Tehran Stock Exchange returns and gold returns to investigate the gold role as a hedge, diversifier and a safe haven for Tehran Stock Exchange. We conduct our study through Threshold Regime Switching model to thoroughly determine the different regimes in the gold coin-stock market relations. Due to the high liquidity of Bahar Azadi gold coins market, we use their market price to represent the gold price in Iran. We also consider the effect of global gold price and USD-IRR exchange rate on gold coin-stock market relation. We find that gold coin-stock market relationship doesn’t depend on specific different regimes and gold coins act as a weak hedge for stock market.

Ardashir the first, founder of the Sassanid Empire, established a new administrative system. The Sassanid kings, as the Achaemenids, did mint the gold and silver coins. During this period, the gold, whenever it would be needed, was used beside the silver at the cast of second currency. Based on the narrations, a vast amount of gold was arrived to the center. The gold was used as the expenditure of war, wage, tribute, cultural memorial or jewelry. By the testimony of resources, most of the gold of the world was mined and used in this era and almost all of gold rade routes were toward Sasanian realm. The title Zarbod is an evidence to make doubt on idea of ceremonial Sasanian gold. Thus the role of Sasanian gold and its function in society and culture must be studied with a new approach. This article aims to analyze the social and economic function of gold and review its proficenicy and currency in Sasanian society. Also it is about to reject this old hypothesis on inefficiency of Sasanid gold on governmental economy and religious society.

The paper aims to examine the price discovery process and the performance of Gold Exchange Traded Funds (ETF) in Iran Mercantile Exchange (IME) for the period 2017/06/10 – 2019/09/18. The study has employed Johansen cointegration and Johansen’s Vector Error Correction Model (VECM) for the price discovery analysis. The results show that the spot prices lead the Gold ETF price during the study period and ETF is only following the spot prices. Also Tracking Error analysis shows that, Gold ETF have neither outperformed nor underperformed the spot price. Price Deviation analysis indicates that Gold ETF is trading lower than the spot price of gold. The entire analysis reveals that although the price discovery takes place in the spot market, Gold ETF have performed as well as physical gold and the slight difference in price with that of Gold is only because of certain fees, which are applicable in the management of Gold ETF. Therefore, the expected price discovery for gold ETF in IME has not been realized.

Gold has always been considered as a strategic commodity in crises. When markets are down, gold acts as a safe haven. Because the price of gold usually does not move with the market prices. The purpose of this research is to investigate the gold market bubble and the possibility of its contagion to the stock exchange. For this purpose, in order to check the existence of a price bubble in the gold market, using (RADF), (SADF) and (GSADF) tests, the price bubble of the gold market was tested and the date of their creation and collapse was determined. To investigate the contagion of the gold market bubble to the stock exchange, a time variable regression model was used. The results indicate the existence of 4 periods of explosive behavior and the existence of multiple price bubbles in the price of gold. Based on this, the bubble periods in the Iranian gold market are related to the periods 1395:07:13-1395:04:13, 1397:09:25-1396:10:17, 1398:06:04-1397:10 09:09 and 1399:12:30–1398:09:19 and the contagion of the price bubble from the gold market to the stock market has also occurred.

Several physical and chemical methods have been studied for synthesis of metal nanoparticles at commercial scale for use in biological and non-biological purposes. Nowadays, the green synthesis or biosynthesis method by plants is the most efficient way for synthesis of nanoparticles. In this study, biosynthesis of gold nanoparticles has done by adding gold nitrate in extract of aerial organs biomass of cumin. The highest conversion of gold ions into nanoparticles of gold was achieved under optimal conditions of 40 °C, pH=10 and 20 minutes. Synthesis of gold nanoparticles surveyed by UV-visible spectroscopy, transmission electron microscope (TEM) and X-Ray diffraction (XRD). Spectrophotometric analysis showing absorbance in 550 nm approved synthesis of gold nanoparticles using extract of aerial organs biomass of cumin . TEM analysis showed spherical shape of gold nanoparticles in range of 2-10 nm. Moreover, XRD analysis showed nano crystals synthesis by extract of aerial organs biomass of cumin.Using nyquist plot, electric conduction comparison between simple carbon dough electrode with its modified counterpart with gold nanoparticles verified the presence of gold nanoparticles in Cumin extract.

The purpose of this study is to apply the system dynamics approach to predict the price of gold in Iran, identify factors affecting the price of gold and simulate the impact of monetary policy on the price of gold in the period 1389-1405. The simulation was performed with Vensim software. The present study simulates the change in liquidity volume, consumer price index and bank interest rates on the gold market in different scenarios. The results show that the price of gold is not only affected by the gold world price and the value of the dollar, but also the control of liquidity and curbing inflation will play a significant role in stabilizing the gold market. The results confirm that the volume of liquidity and the consumer price index have a direct impact and a significant role in increasing the price of gold. The findings also show that changes in bank interest rates have no effect on changes in gold prices.

This article lists a number of geological data on the conditions of formation of some major gold deposits in the conglomerates of the Earth\'s crust. We analyze the metallogenic, tectonic, stratigraphic and other factors controlling the formation of gold-bearing conglomerates in certain fields, such as the Witwatersrand (S. Africa) and Darwaz (Tajikistan). The following tectonic factors play the leading role in controlling the formation of deposits of gold-bearing conglomerates in the Earth\'s crust:  Epochs of mountain building of different ages in folded belts;  Epochs of mountain building in activation of consolidated gold ore provinces in the domed uplifts of ancient shields, median areas and in areas with complete folding;  The role of lithogenesis of the molasse cycle, transgressions and angular unconformity in the formation of gold-bearing conglomerates in a large area;  Synchroneity with mountain building in gold ore provinces of different, intermountain molasse and marginal basins of various ages; and imposed volcanic and terrigenic conglomeratic molasse basins in activated gold ore provinces  Volcanic belts and deep faults. There are three industrial types of gold-bearing conglomerates: ancient Precambrian (indurated) sedimentary-metamorphosed placer, Phanerozoic cemented placer, and younger, weak, friable Pliocene-Pleistocene placers. We give some details about the methods for their exploration and financial costs for the development of selected industrial types of gold-bearing conglomerates. In this article, it is noted that during the Sassanian and the Mongolian Empire a certain amount of native gold was extracted from the Late Alpine molasse conglomerates which formed during the activation of gold ore area of the major Iranian middle massif. By analogy with the geological conditions of formation of deposits of gold-bearing conglomerates in the Earth\'s crust, the geological search criteria for deposits of gold-bearing conglomerates in some orogenic and widespread activated imposed conglomeratic molasse basins of Iran are given. A number of promising molasse conglomeratic basins are indicated: Mashhad intermountain deflection, as well as a number of superimposed molasse basins in the active superimposed volcano- plutonic belt of Iran, in particular Lut Block, middle massif, Tabriz, Ahar, and other superimposed molasse basins in the large Sabalan ring structure. In conclusion, we propose the development of selected areas and the establishment of new major resources of the gold - placer industry of Iran.

In this study, the biosynthesis of gold nanoparticles by Penicillium chrysogenum, isolated from Ahar copper mine, was investigated. The gold nanoparticles were synthesized by reducing the aqueous gold ions using the culture supernatant of the filamentous fungi. The UV–vis spectrum displayed a characteristic peak at 532 nm that is very specific for gold nanoparticles. The XRD spectrum confirmed the presence of crystalline gold nanoparticles. Transmission electron microscopy exhibited the intracellular formation of gold nanoparticles in spherical, triangle and rod shapes with the size range of 5 to 100 nm.

According to the unique properties and many applications of nano gold powder, it was prepared from an acid leaching tail solution. The low value residual gold ions existed in acid leaching tail solution in Mouteh gold mine in Iran with fellow heavy metals as pollutants (Fe2+, Cu2+, and Zn2+). Preparation of nano gold particles is achieved by two steps: First, by addition of ammonia as separation step and second by using the suitable reagents for precipitation and extraction step. Control conditions include pH, residence time, temperature, agitation, molar ratio of reducing agents to reagents. The optimum results show that nano gold powder was prepared by temperature of 250 °C, urea to gold molar ratio of 3:1, and reduction time of 20 min. Also, heat treatment improves dispersion of nano sized gold particles. The properties of gold nano powders were evaluated by SEM, A.A and UV-Vis spectroscopy methods and the size of particles were about 80 to 90 nm.