Waste Aggregate Production via Wet Maturing
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Solution Overview
Problem
The production of aggregates for road foundations is costly due to the need for additional raw materials and bonding agents like slaked lime or hydraulic lime, despite the use of waste materials, which increases the overall expense.
Innovation Solution
A process that selects and mixes waste materials containing quicklime and silicates, with the inclusion of heavy metals, and undergoes a maturing step involving wet storage to convert these materials into chemically stable, insoluble products, eliminating the need for additional materials and reducing pollution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If slaked lime or hydraulic lime is added to the mixture of waste materials, then the aggregates achieve better bonding and structural properties, but the production cost increases due to the need for additional raw materials
Solution Approach 1:
The waste materials themselves contain the bonding agents needed for aggregate production. The quicklime and silicates present in the waste materials react with each other and with water to form binding compounds, eliminating the need to add external bonding agents like slaked lime or hydraulic lime. The waste materials serve dual purposes: as the aggregate matrix and as the bonding agent.
Solution Approach 2:
The patent changes the chemical parameters of the waste materials by controlling their moisture content and allowing them to mature. By adjusting the water content and storage time, the quicklime and silicates undergo chemical reactions that transform them into effective bonding agents. This parameter control enables the waste materials to develop the necessary binding properties without adding external materials.
2Quantity of substance
If waste materials containing heavy metals are used, then production costs are reduced by utilizing only waste materials, but pollution concerns arise from the presence of heavy metals
Solution Approach 1:
The patent converts the harmful heavy metals present in waste materials into beneficial, stable compounds. Through the maturing process where waste materials are stored wet, chemical reactions occur that transform the heavy metals into insoluble, stable forms. This process turns the harmful aspect (presence of heavy metals) into a benefit (creation of stable, non-polluting compounds) while maintaining the economic advantage of using only waste materials.
Solution Approach 2:
The patent employs a temporary wet storage phase during which the waste materials undergo chemical transformation. This temporary wet state allows the quicklime and silicates to react and stabilize the heavy metals, after which the materials can be dried and used as aggregate. The temporary wet storage is a cost-effective method to achieve stabilization without requiring expensive additional treatment processes.
3Stability of the object's composition
If the waste materials are stored wet for maturing, then the chemical stability and insolubility of the products improve, but the process duration and storage requirements increase
Solution Approach 1:
The patent performs preliminary crushing and sorting of the waste materials before the maturing storage phase. By preparing the waste materials in advance (crushing to appropriate size, removing large contaminants), the subsequent maturing process requires less time and effort. This preliminary action reduces the overall process duration while still achieving the necessary chemical stability through the wet storage maturing phase.
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 process lowers production costs by utilizing only waste materials, effectively recycles pollutants, and produces inert, non-polluting aggregates suitable for road foundations, while maintaining a lower implementation cost.
Implementation Method 1
the combined action of water and of the substances carried in solution (Me n+, Ca++, etc.) chemically attacks (definitively breaking them) the calcium - oxygen electrostatic secondary bonds
Implementation Method 2
CaO + H2O → Ca(OH)2
Implementation Method 3
CaO + CO2 → CaCO3
Implementation Method 4
the combined action of water and of the substances carried in solution (Me n+, Ca++, etc.)
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A process for producing aggregates for making road foundations and the like comprises the following operating steps: a step (100) of selecting a plurality of types of waste materials (10) containing, amongst other components, quicklime, silicates and heavy metals; a step (110) of mixing the materials in predetermined proportions to obtain a mixture of the waste materials (10); a step of wetting the mixture with water; and a step (120) of storing the mixture for a predetermined period of time, repeatedly wetting it with water during the entire period, so that during the storage period, chemical reactions take place converting the various waste materials (10) into products which are chemically inert and nonpolluting.