Vacuum Distillation of Gold-Silver Alloys with Directed Vapor Flow

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Solution Overview

Problem

Current vacuum distillation methods for separating gold and silver from gold-silver alloys suffer from low condensation intensity and accuracy due to inefficient vapor-gas flow management and heat loss, leading to reduced crystal nucleation and metal separation efficiency.

Innovation Solution

The method involves heating the gold-silver alloy in a high vacuum with a graphite crucible and using a graphite cone head and ceramic heat-protection screen to direct and increase the vapor-gas flow pressure, combined with a system of hemispherical condensers and a restricting titanium screen to enhance condensation efficiency and reduce heat loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a partition without additional devices is used to separate the evaporation chamber from the condensation chamber, then the device complexity is reduced, but the vapor-gas flow is not directed properly causing pressure equalization and decreased condensation intensity

Engineering Contradiction:
Improvechamber separation structureVSAvoidcondensation intensity
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The partition is segmented into multiple functional zones: a first partition section with a first orifice for controlled vapor flow, a second partition section with a second orifice positioned at a lower level, and a collecting chamber. This segmentation enables directional vapor-gas flow control while maintaining structural simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The partition with multiple orifices acts as an intermediary device between the evaporation chamber and condensation chamber. It mediates the vapor-gas flow by controlling its direction and pressure, preventing backflow while maintaining the separation function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If no additional flow direction devices are installed, then the device complexity is reduced, but the vapor-gas flow moves out of the condensation chamber back into the evaporation chamber causing pressure equalization

Engineering Contradiction:
Improveflow control structureVSAvoidpressure control accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The partition is divided into multiple sections with orifices at different heights and positions. The first orifice is positioned higher to control initial vapor flow, while the second orifice is positioned lower to control pressure and prevent backflow, achieving precise pressure control through segmented flow control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flow control is extended into the vertical dimension by positioning orifices at different heights. The first orifice is located in the upper region while the second orifice is in the lower region, creating a vertical flow path that prevents horizontal backflow and maintains pressure differential.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If a water-cooled condenser is used without protective screens, then the device complexity is reduced, but heat loss from the crucible is significant causing low condensate formation rate

Engineering Contradiction:
Improveheat protection structureVSAvoidcondensate formation rate
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

Protective screens made of heat-resistant material are introduced as intermediary elements between the crucible and the condenser. These screens mediate the heat transfer, reducing direct heat loss from the crucible while maintaining the temperature gradient necessary for condensation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The heat that would otherwise be lost to the environment is redirected through the protective screens to preheat the vapor-gas mixture before it reaches the condenser, converting harmful heat loss into beneficial preheating that enhances condensation efficiency.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Device complexity

If the condenser is arranged at a significant distance from the molten metal surface, then the device complexity is reduced, but thermal effect on the condenser surface is insufficient causing no crystal nucleation

Engineering Contradiction:
Improvecondenser positioningVSAvoidcrystal nucleation rate
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The condensation zone is segmented into multiple regions with different temperature characteristics. The condenser is positioned to receive vapor-gas flow that has been preheated by the protective screens, creating localized high-temperature zones that promote crystal nucleation while maintaining overall system simplicity.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly increases the intensity and effectiveness of silver condensation, resulting in high-purity metal separation with reduced metal loss and energy consumption, achieving a usable production yield of 99.93% with minimal environmental impact.

Implementation Method 1

heating the initial raw material in a high vacuum to metal evaporation temperature, evaporating and condensing the metals from the vapour-gas mixture

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

the vapour phase is transformed into a solid or liquid state and condenses

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

vacuum distillation method for producing metals of high purity

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP3029165B1Method for separating gold-silver alloys by vacuum distillation and device for realization thereof
Publication Date: 2019.04.03 IKOI SPA
  • EP3029165B1 patent drawingFigure 1

AI summary

The invention relates to non-ferrous metallurgy and to the metallurgy of precious metals, in particular, to the separation technology for gold-silver alloys and mixtures using the vacuum distillation method, for producing high-purity metals. Separating gold-silver alloys is performed using an apparatus comprising a high vacuum chamber with a melting crucible arranged therein; a heating element in the form of an induction coil is arranged around the crucible, which induction coil is configured in association with a tilting device capable of tipping over; at least one condenser with a number of entrainment separators; and an ingot mould. The apparatus is further provided with a cone head mounted above the melting crucible, which creates a directed motion of a vapour-gas mixture flow from the crucible into the condensation zone, thus increasing the pressure of the vapour-gas mixture; the apparatus is further provided with a restricting screen arranged in the vapour-gas mixture condensation zone, a heat-protection screen located between the winding of the induction coil and the crucible. The apparatus is provided with three hemispherically shaped condensers. The use of the claimed inventions makes it possible to considerably increase the apparatus performance, the purity of he separated metals, and to decrease the process cycle time.