How to determine the volume excess of HCl, HNO3 for HAuCl4.3H2O production ?

protocol Protocol: Various Modes of Spinal Cord Injury to Study Regeneration in Adult Zebrafish

Dear Sir,


We couldn't figure out the excess weight or volume of HCl and HNO3 for the production of 1 Kg HAuCl4.3H2O, we have used all the equations.


Thanks in advance

Best regards,

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BP-Exchange Assistant Answered Nov 22, 2022

Bio-protocol

The authors have supplied a detailed preprint protocol on Bio-protocol Preprint. We have found the following information from "Protocol Acid chloroauric.docx". Hope it will be helpful for you.



This protocol allows to calculate the life cycle inventory data to produce 1 kg of acid chloroauric trihydrate (HAuCl4.3H2O) based on the assumptions established by the Ecoinvent framework and the data collected from literature.


Input material is calculated based on stoichiometric reactions

1.The reactions that were involved are:


Au + 3HNO3 + 4HCl → HAuCl4 + 3NO2 + 3H2O

3HCl + HNO3 → Cl2 + 2H2O + NOCl


2.The mass balance was obtained from the protocol described in the Handbook of preparative inorganic chemistry (S. Gross, 2008), as follows:


  • Preparation of aqua regia: Aqua regia is produced by mixing 75% HCl and 25% HNO3. Density of HNO3 is 1.42 g/mL (16 M) and the density of HCl is 1.18 g/mL (12 M). Therefore, aqua regia composition is 20 wt.% HNO3, 26.5 wt.% HCl, and 53.2 wt.% H2O.


  • Production of HAuCl4: 70 mL of aqua regia is mixed with 0.7 g of metallic gold. This mixture is stirred at 50 °C. When metallic gold is completely dissolved, HCl is slowly added until HNO3 is completely removed. This reaction produces a gas stream with the following composition: 1.4 wt.% NO2, 51.0 wt.% Cl2, 47.1 wt.% of NOCl, and 0.5 wt.% of HCl. The flow rate of the gas stream is 35.59 g


  • Decomposition of NOCl in the atmosphere results in the production of Cl2 and NO. Therefore, 16.76 g of NOCl produces 9.09 g Cl2 and 7.68 g NO.


  • The composition of the liquor obtained after the reaction is: 0.4 wt.% HNO3, 26.1 wt.% HCl, 73.0 wt.% H2O, and 0.5 wt.% HAuCl4.


  • Purification of HAuCl4: To purify HAuCl4, the aforecited solution is heated to concentrate the solution. Distilled water is added to control the temperature between 70 and 80 °C. During evaporation HCl, HNO3, and water is removed and a solution of HAuCl4 is discarded.


3.Based on the above the following quantities were included in the life cycle inventory to produce 1 kg of HAuCl4.3H2O:


  • 0.54 kg metallic gold


  • 13.57 kg HNO3


  • 68.07 kg HCl


4.We employed the Ecoinvent V 3.4 to calculate the providers. According to Ecoinvent the following providers were included.


  • Gold production |gold| APOS, S – Row: This data set described the beneficiation, concentration, and refinement of gold. It includes energy and water consumption, land use, transportation, transports, waste disposal as well as emissions to air and water.


  • Nitric acid production, product in 50% solution state |Nitric acid, without water, in 50% solution| APOS, S – RER:


  • Market for Hydrochloric acid, without water, in 30% solid state, APOS – S, RER:


Detailed information of the laboratory protocol is found:

Detailed information of the mass balance performed to calculate the production of chloroauric acid trihydrate is found:

  • Sanchez, N., Ruiz, R., Rödl, A., & Cobo, M. (2021). Life cycle inventory data for power production from sugarcane press-mud. Data in Brief, 37, 107194.


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