Cement Additive Reducing Hexavalent Chromium
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Solution Overview
Problem
Existing cement manufacturing processes using industrial wastes result in the presence of carcinogenic heavy metals like hexavalent chromium, leading to health issues and requiring methods that maintain cement strength and physical properties while reducing these contaminants.
Innovation Solution
A cement additive comprising charcoal, silicate, ferrous sulfate heptahydrate, and ferrous chloride tetrahydrate, with optional additives like diatomite, tin sulfide, or antimony, is used to reduce hexavalent chromium to trivalent chromium, effectively adsorbing and stabilizing heavy metals, thereby preventing oxidation back to hexavalent form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If industrial wastes are used as raw materials in cement manufacturing, then production cost is reduced and industrial waste disposal is achieved, but carcinogenic heavy metals such as hexavalent chromium are generated
Solution Approach 1:
The patent applies this principle by using ferrous sulfate and ferrous chloride as reducing agents to convert harmful hexavalent chromium (Cr6+) into less toxic trivalent chromium (Cr3+). The harmful heavy metals generated from industrial waste utilization are transformed into a safer form through chemical reduction, allowing the cement to maintain both cost-effectiveness and reduced toxicity.
Solution Approach 2:
The patent introduces ferrous sulfate and ferrous chloride as intermediary substances that mediate between the harmful hexavalent chromium and the desired safe cement product. These intermediaries act as reducing agents that facilitate the conversion of Cr6+ to Cr3+, serving as a bridge to eliminate the harmful effect while preserving the benefits of industrial waste utilization.
2Object-generated harmful factors
If reducing agents are added to reduce hexavalent chromium, then hexavalent chromium levels are lowered, but cement strength and intrinsic physical properties may deteriorate
Solution Approach 1:
The patent applies this principle by carefully controlling the dosage parameters of ferrous sulfate and ferrous chloride within specific ranges (ferrous sulfate: 0.1-5 wt%, ferrous chloride: 0.1-5 wt%). By optimizing these concentration parameters, the reduction of hexavalent chromium is achieved while minimizing the negative impact on cement strength and physical properties.
Solution Approach 2:
The patent uses a composite approach by combining ferrous sulfate and ferrous chloride together rather than using a single reducing agent. This composite formulation enhances the reduction efficiency of hexavalent chromium while the synergistic effect helps maintain cement strength, as each component contributes differently to the overall performance.
3Object-generated harmful factors
If ferrous sulfate or ferrous chloride alone is used to reduce hexavalent chromium, then the reducing effect is limited, but using both increases cost and complexity
Solution Approach 1:
The patent merges ferrous sulfate and ferrous chloride into a single cement additive composition. By combining these two reducing agents, the patent achieves synergistic effects that enhance hexavalent chromium reduction efficiency beyond what either agent could achieve alone, while managing the complexity through a unified formulation approach.
Solution Approach 2:
The combined ferrous sulfate and ferrous chloride formulation serves multiple functions: it acts as a reducing agent for hexavalent chromium, provides sulfur and chlorine elements that can contribute to cement chemistry, and maintains cement workability. This multi-functionality justifies the slightly increased complexity by delivering comprehensive benefits.
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 cement additive significantly reduces detectable levels of hexavalent chromium and other heavy metals, maintains cement strength and physical properties, and is applicable in wastewater disposal processes without increasing production costs.
Implementation Method 1
ferrous sulfate heptahydrate and ferrous chloride tetrahydrate, with optional additives like diatomite, tin sulfide, or antimony, is used to reduce hexavalent chromium to trivalent chromium
Implementation Method 2
effectively adsorbing and stabilizing heavy metals, thereby preventing oxidation back to hexavalent form
Data Source
AI summary
The present invention relates to a cement additive and a method for producing same, wherein carcinogens, including heavy metals such as hexavalent chromium and the like, generated from cement are removed while maintaining the strength and characteristic physical properties of cement. Moreover, the cement additive according to the present invention can provide cement that does not become oxidized by heat into hexavalent chromium.