Eosilix - Swiss Solar Silicon

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method for purifying metallurgical grade silicon, up to obtaining solar grade silicon suitable for the production of solar cells IntroductionThe following project idea concerns a method and an equipment for silicon purification. In particular, it is a method for metallurgical-grade silicon purification until solar-grade silicon suitable for the production of solar cells is obtained.The increasing requirements of energy production in an environmentally sustainable way and the needs to diversify energy production methods have acted as a springboard for investments in renewable energy sources.Many countries around the world are investing more and more in solar energy production through photovoltaic panels.World production of 'clean' energy is forecast to grow by 2,400 gigawatts in the next 4 years.In the last year, the demand for photovoltaic resources almost doubled compared to the previous year and was also the most demanded of all renewable sources.To this day, a large part of the starting material for the production of solar-grade silicon is waste material from the processing of silicon used by the electronics industry for the manufacture of semiconductors (Electronic Grade), which, requiring a purity in the order of 98-99%, even at scrap level meets the specifications of silicon suitable for solar cell production.The process of producing silicon suitable for solar cell production is complicated, time-consuming and energy-intensive, as it requires a purity level of at least 99.999%Although the cost of metallurgical-grade silicon is relatively low (just over 1CHF/kg with peaks of 2.2CHF/kg recently) even partially purified, the impurity content of phosphorus and boron remains too high to produce solar cells and even though modern purification techniques have made great technological advances, these processes for producing solar-grade silicon still involve a fairly high cost, currently around 20-30 CHF/kg.The aim of many research projects has therefore been to produce silicon with a low level of impurities and at low cost. The main focus has been on reducing the cost of the silicon purification process and making it more efficient through chemical methods.IdeaThis idea involves the problem of purifying metallurgical grade silicon without using chemical methods and minimising the costs of the purification process and the equipment that performs it. This is achieved by a new purification method involving localised heating on metallurgical grade silicon ingots in a protective atmosphere.This project idea can be further developed, integrated and explored to improve the purification stage, so as to further reduce the concentration of boron and phosphorus, which, due to their segregation constant, are the most difficult impurities to remove.AdvantagesThe method requires extremely limited energy and gas consumption since it does not involve the melting of metallurgical grade silicon ingots.The equipment, on the other hand, consists of simple components that are readily available on the market and can be amortised within a few years of operation.Moreover, it allows a reduction in production costs by using power only when necessary.A further advantage is that it significantly reduces the time required to produce solar-grade silicon from metallurgical-grade silicon ingots.Expected outcome:Potentially this project idea, only in relation to Switzerland, could lead to energy savings of 100 GWh per year and CO2eq savings more than 100kt per year.

Project Idea Metadata

• Project Idea Name: Eosilix - Swiss Solar Silicon
• Date: 2/3/2023 2:39:44 PM
• Administrators:
  • Andrea Tonini

Project Idea Description

Introduction

The following project idea concerns a method and an equipment for silicon purification. In particular, it is a method for metallurgical-grade silicon purification until solar-grade silicon suitable for the production of solar cells is obtained.

The increasing requirements of energy production in an environmentally sustainable way and the needs to diversify energy production methods have acted as a springboard for investments in renewable energy sources.

Many countries around the world are investing more and more in solar energy production through photovoltaic panels.

World production of 'clean' energy is forecast to grow by 2,400 gigawatts in the next 4 years.

In the last year, the demand for photovoltaic resources almost doubled compared to the previous year and was also the most demanded of all renewable sources.

To this day, a large part of the starting material for the production of solar-grade silicon is waste material from the processing of silicon used by the electronics industry for the manufacture of semiconductors (Electronic Grade), which, requiring a purity in the order of 98-99%, even at scrap level meets the specifications of silicon suitable for solar cell production.

The process of producing silicon suitable for solar cell production is complicated, time-consuming and energy-intensive, as it requires a purity level of at least 99.999%

Although the cost of metallurgical-grade silicon is relatively low (just over 1CHF/kg with peaks of 2.2CHF/kg recently) even partially purified, the impurity content of phosphorus and boron remains too high to produce solar cells and even though modern purification techniques have made great technological advances, these processes for producing solar-grade silicon still involve a fairly high cost, currently around 20-30 CHF/kg.

The aim of many research projects has therefore been to produce silicon with a low level of impurities and at low cost. The main focus has been on reducing the cost of the silicon purification process and making it more efficient through chemical methods.

Idea

This idea involves the problem of purifying metallurgical grade silicon without using chemical methods and minimising the costs of the purification process and the equipment that performs it. This is achieved by a new purification method involving localised heating on metallurgical grade silicon ingots in a protective atmosphere.

This project idea can be further developed, integrated and explored to improve the purification stage, so as to further reduce the concentration of boron and phosphorus, which, due to their segregation constant, are the most difficult impurities to remove.

Advantages

The method requires extremely limited energy and gas consumption since it does not involve the melting of metallurgical grade silicon ingots.

The equipment, on the other hand, consists of simple components that are readily available on the market and can be amortised within a few years of operation.

Moreover, it allows a reduction in production costs by using power only when necessary.

A further advantage is that it significantly reduces the time required to produce solar-grade silicon from metallurgical-grade silicon ingots.

Expected outcome:

Potentially this project idea, only in relation to Switzerland, could lead to energy savings of 100 GWh per year and CO2eq savings more than 100kt per year.

method for purifying metallurgical grade silicon, up to obtaining solar grade silicon suitable for the production of solar cells