Precipitated Silica Production Using Concentrated Acid
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Solution Overview
Problem
Existing processes for preparing precipitated silica using dilute acids are inefficient in terms of productivity and energy consumption, and require excessive water usage.
Innovation Solution
A new process involving the reaction of silicate with a concentrated acid, such as sulfuric acid, to achieve a suspension of silica, followed by specific pH adjustments and additions of alkali metal silicate, which enhances productivity and reduces energy and water consumption while maintaining comparable physicochemical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dilute acid is used for precipitation reaction, then the process is easier to operate, but productivity is low and energy consumption is high
Solution Approach 1:
The patent changes the concentration parameter of the acid from dilute to concentrated (at least 30% by mass), which fundamentally alters the reaction kinetics and precipitation efficiency, thereby resolving the contradiction between ease of operation and productivity
Solution Approach 2:
The patent prepares an initial aqueous starter culture with specific silicate concentration (less than 20 g/L) before adding acid, which pre-conditions the reaction medium to optimize subsequent precipitation when concentrated acid is added, improving productivity while maintaining operational control
2Device complexity
If dilute acid is used for precipitation reaction, then the process is simpler, but energy consumption and water usage are excessive
Solution Approach 1:
The patent changes the acid concentration parameter from dilute to concentrated (at least 30% by mass), which reduces the total volume of acid solution required and consequently reduces energy consumption for heating and water usage for dilution and washing, while maintaining process simplicity
Solution Approach 2:
The patent adds acid until at least 50% of the amount of M2O present in the initial starter culture is neutralized, which is a controlled excessive action that ensures complete precipitation efficiency while minimizing unnecessary reagent use and associated energy consumption
3Productivity
If concentrated acid is used for precipitation reaction, then productivity is improved, but the process becomes more complex
Solution Approach 1:
The patent prepares an initial aqueous starter culture with controlled silicate concentration before adding concentrated acid, which pre-conditions the system to handle the concentrated acid safely and efficiently, thereby maintaining process simplicity while achieving high productivity
Solution Approach 2:
The patent monitors and controls the pH of the reaction medium during the precipitation process, using feedback control to add acid and silicate in appropriate amounts to maintain pH between 2.5 and 5.3, which simplifies operation despite using concentrated acid
4Use of energy by moving object
If concentrated acid is used for precipitation reaction, then energy consumption is reduced, but manufacturing precision may be affected
Solution Approach 1:
The patent uses pH feedback control to maintain the reaction medium pH between 2.5 and 5.3 during concentrated acid precipitation, which ensures consistent physicochemical characteristics of the precipitated silica while benefiting from the energy efficiency of concentrated acid
Solution Approach 2:
The patent carefully controls multiple parameters including silicate concentration in starter culture (less than 20 g/L), acid concentration (at least 30% by mass), and pH range (2.5-5.3), which collectively ensure manufacturing precision while reducing energy consumption compared to dilute acid methods
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
The process achieves improved productivity and energy efficiency, with a potential 10-40% gain in precipitated silica production and reduced water usage, while maintaining the properties of silica comparable to those produced by traditional methods.
Implementation Method 1
preparing precipitated silica comprising the reaction of a silicate with at least one acid, thereby obtaining a silica suspension
Implementation Method 2
acid is added to said initial starter culture until at least 50% of the amount of M2O present in said initial starter culture is neutralized
Data Source
AI summary
The invention relates to a method for producing precipitated silicas, comprising: (i) forming a starter having an alkali metal silicate M concentration of less than 20 g/L; (ii) adding acid thereto until at least 50% of the quantity of M2O is neutralised; (iii) adding silicate and acid simultaneously, such that the consolidation rate is greater than 4 and at most 100; (iv) adding acid until the pH measures between 2.5 and 5.3; (v) bringing the reaction medium into contact with the acid and the silicate, such that the pH measures between 2.5 and 5.3. According to the invention, the acid used in at least one of the steps is a concentrated acid, preferably selected from the group containing sulphuric acid having a concentration of at least 80 wt.-%, in particular at least 90 wt.-%, acetic acid or formic acid having a concentration of at least 90 wt.-%, nitric acid having a concentration of at least 60 wt.-%, phosphoric acid having a concentration of at least 75 wt.-%, hydrochloric acid having a concentration of at least 30 wt.-%.