Amount Of CaCO3 Research Articles

Synergistic Effects of Ternary Microbial Self-Healing Agent Comprising Bacillus pasteurii, Saccharomyces cerevisiae, and Bacillus mucilaginosus on Self-Healing Performance in Mortar

In order to prevent structural damage or high repair costs caused by concrete crack propagation, the use of microbial-induced CaCO3 precipitation to repair concrete cracks has been a hot topic in recent years. However, due to environmental constraints such as oxygen concentration, the width and depth of repaired cracks are seriously insufficient, which affects the further development of microbial self-healing agents. In this paper, a ternary microbial self-healing agent composed of different proportions of Bacillus pasteurii, Saccharomyces cerevisiae, and Bacillus mucilaginosus was designed, and its crack repair ability was evaluated. When the mixing ratio was 7:1:2, the cell concentration was the highest, the precipitation amount of CaCO3 was the highest, and the crystallinity of calcite crystal was the highest. Compared to the single microorganism, the mortar specimens with ternary microorganisms had the largest repair area (up to 100%) and the deepest repair depth (CaCO3 presents at 9–12 mm from the crack surface). This is because when the concrete breaks, all three microorganisms are activated by water, O2, and CO2. Saccharomyces cerevisiae and Bacillus mucilaginosus accelerated the growth of Bacillus pasteurii and more mineralized products; CaCO3 was rapidly formed and quickly filled on the crack surface. When CaCO3 seals the surface of the crack, the internal Saccharomyces cerevisiae and Bacillus mucilaginosus continue to play a role. Bacillus mucilaginosus can accelerate the dissolution of CO2 produced by the anaerobic fermentation of Saccharomyces cerevisiae and the hydrolysis of CO32−, thereby improving the repair of the crack depth direction.

A Study of the EH36 Surface Sediment Layer under Joint Protection from Seawater Electrolysis Antifouling and Impressed Current Cathode Protection (ICCP) in a Marine Environment

A joint protection device for seawater electrolysis antifouling and ICCP was constructed, and comparative experiments were conducted to study the composition of the EH36 surface deposition layer under joint protection in a marine environment. Surface morphology analysis, energy-dispersive spectroscopy (EDS) imaging analysis, and X-ray diffraction (XRD) composition analysis were performed on the surface deposition layers of the experimental samples. The experimental results showed that under joint protection, a sedimentary layer was rapidly formed on the surface of EH36 to isolate the seawater medium, and this layer was mainly composed of Mg(OH)2 and a small amount of CaCO3. There was no corrosion on the surface of the EH36 substrate. When only ICCP was used, a relatively thin layer of calcium magnesium was deposited on the surface of EH36. Marine fouling organisms adhere to the surface of calcium and magnesium sedimentary layers and the EH36 substrate, and their attachment affects the formation of calcium and magnesium sedimentary layers. Moreover, marine fouling organisms cause corrosion on the surface of the EH36 substrate. The joint protection of seawater electrolysis antifouling and ICCP can simultaneously prevent electrochemical corrosion and marine biological fouling corrosion on the surface of EH36.

Effect of white mud on carbonation resistance of alkali activated slag

White mud (WM) is a solid waste produced in the process of papermaking and it remains to be effectively utilized. It contains a large amount of CaCO3 and residual alkali metal ions. This paper aims to explore the effect of WM on carbonation resistance of alkali activated slag. The changes in mechanical properties and microstructure of alkali activated white mud/slag (AAWS) after natural carbonation and accelerated carbonation were analyzed. The results indicate that the mechanisms of natural carbonation and accelerated carbonation are different. The carbonation depth achieved in 90 days of natural carbonation can be reached in just 14 days of accelerated carbonation. Samples with 15 wt% WM blended possesses the smallest carbonation depth and the highest compressive strength. WM can effectively mitigate the natural carbonation of AAWS by dissolving Mg2+ and Ca2+. Mg2+ can migrate to increase the solubility of calcite, promote the generation of hydrotalcite to absorb carbon dioxide, and reduce the carbonation degree. Ca2+ will migrate after the carbonation and decalcification of the gel product and reduce the decalcification sensitivity. This study offers a sustainable approach for improving the carbonation resistance of AAWS.

A superhydrophobic coating prepared by carbonated fly ash: Properties and mechanism

In this paper, carbonated fly ash (CFA) was prepared by aqueous carbonation of fly ash (FA) and carbide slag (CS) with CO2. It was bonded with room-temperature vulcanized rubber (RTV) to fabricate a superhydrophobic coating. The wettability, self-cleaning property, surface lyophobicity and water absorption of cement mortar coated with CFA/RTV coating were investigated. Then, the morphology and roughness of CFA, and quantity of nano CaCO3 product were characterized. Meanwhile, the effects of carbonation conditions (CS content, temperature, pH) on the performance of CFA/RTV coating were evaluated. The results showed that CaCO3 produced on CFA surface increased with CS content increasing. Although hydrophobicity was increased as CS content was up to 10 %, it decreased when CS content was more than 10 %. Temperature increased from 20 °C to 60 °C barely affected CaCO3 amount, surface roughness, wettability and water absorption of CFA/RTV coating. CFA/RTV coating carbonated at pH 7 formed the most CaCO3, and had the highest surface roughness, hydrophobicity and resistance to water absorption of coating. The carbonation condition of 10 % CS content, 20 °C carbonization temperature and pH 7 was optimal to obtain the largest contact angle (CA) of 161.2° and surface roughness of 478 nm. The mechanism of hydrophobicity (contact angle and sliding angle) for CFA/RTV coating was strongly associated with surface roughness in an exponential relationship. Moreover, the trend of resistance to water absorption was consistent with hydrophobicity of the coating. The developed superhydrophobic CFA/RTV coating had remarkable properties of self-cleaning, surface lyophobicity and resistance to water absorption.

Evaluation of plastic injection molding for PA6/ABS/CaCO3 nanocomposites using Taguchi method and Moldflow simulation approach

Nowadays, nanocomposites are widely used in the industry. Polymer nanocomposites are widely used in the automotive industry because they have very favorable properties. These properties, including mechanical, electrical, and thermal characteristics, change depending on the combination of materials used in composite synthesis. In this paper, the injection molding of an automobile part called a control arm protector is investigated. Since warpage and shrinkage are general and important challenges in injection molded parts, Taguchi test design and Autodesk Moldflow® simulation approach are used to find the best injection condition for the mentioned part. To perform this, PA6/ABS polymer composite combined with nano CaCO3 is used. Three main injection molding process parameters, including melt temperature, mold temperature, and injection pressure, as well as nano CaCO3 amount, are evaluated. Moreover, analysis of the gate location is investigated. In the following, an analysis of variance is conducted to identify the significant parameters. Regression correlations were also established. Finally, optimization of the process is carried out by the desirability method.

Natural Light Rechargeable Night Peal-like Coatings for Expressway

Traditional roadway lighting is intended to provide safe guidance for drivers and pedestrians, but the large-scale application of roadway lighting has resulted in significant energy consumption and light pollution. However, road markings prepared by luminous coating are a kind of multi-functional road marking that can meet the needs of highway lighting at night and save energy. Here, CaAl2O4:Eu2+,Nd3+,Gd3+ blue long-afterglow phosphor is obtained by the high-temperature solid-state method, and the blue luminescent coating is synthesized by the blending method. The phase composition, microscopic morphology, luminescence properties and water resistance of the phosphor and luminescent coatings are characterized. The best components and processes of the luminescent coating are explored to meet the application of an expressway. Considering the afterglow’s performance, the optimal calcination temperature of the phosphor is determined to be 1300 °C. The afterglow of the phosphor can be over 8 h after 2 h of daylight excitation. The addition of 1.25% SiO2 to the luminescent coating improves the uniformity of the components, and the incorporation of 3.5% CaCO3 improves the denseness of the coating. When the coating thickness is 0.8mm, the luminescent coating can achieve the best luminous effect. After 120 h of immersion in water, the afterglow intensity of the luminescent coating reduced to 70% of the original, which has excellent water resistance. The blue luminescent coating with the addition of appropriate amounts of CaCO3 and SiO2 improves the dispersion as well as the densification of the components in the coating to achieve the best luminescent effect. In the Shenyang area, different weather conditions (cloudy, sunny, rainy) have no significant effect on the afterglow performance of the luminescent coatings, all of which can achieve over 5 h of afterglow and are suitable for expressways.

Characterization of CDW types by NIR spectroscopy: Towards an automatic selection of recycled aggregates

The petrographic and mechanical heterogeneity of construction and demolition waste (CDW) strongly affects the physic-mechanical performance of new concrete and mortar mixes (RAC: recycled aggregate concrete and RAM: recycled aggregate mortar) made with these recycled aggregates (RA). It is thus extremely important to quickly discriminate and sort them in groups of materials with homogeneous petrography, similarly to primary natural raw materials. Eighteen CDW samples, divided in six groups (natural stones, concrete, bricks, perforated bricks, roof tiles and tiles), from the Abruzzo region (central Italy) are analysed by both micro-X-ray fluorescence energy-dispersive spectroscopy (XRF-EDS) and hyperspectral imaging (HSI), in particular in the short wavelength infrared range (SWIR). Every SWIR spectrum is characterized by three regions of absorption at the following wavelength ranges: 1330–1680 (I), 1830–2140 (II) and 2140–2400 nm (III), displaying the lowest, highest and intermediate intensities, respectively. The first and second wavelength regions are linked to O–H and H–O–H motions, whereas the highest wavelength range is linked to atoms bonded to the O–H environment and/or to the carbonate group. According to previous analysis and to the micro-XRF-EDS surface chemistry, the amount of CaCO3 is rich to very rich for concrete and natural stones, intermediate to absent for masonries and absent for tiles. The intensity or area (%) of the absorption component vibrating at about 2345 nm is directly proportional to the amount of CaO (CaCO3 and CO2), and inversely to SiO2 and Al2O3. Therefore, SWIR can rapidly detect and separate CDW as a function of their carbonate to aluminosilicate contents, i.e. concrete and natural stones made with limestone vs masonries and tiles. The attained outcomes are of paramount importance either for routinely screening or in post-disaster circumstances.

A new method for improving the resistance of cement-based materials to carbonic acid water corrosion: Carbonation curing and further water curing

Accelerated carbonation curing has several advantages compared with traditional moisture curing in terms of decreasing the duration time of early curing and improving the mechanical properties, dimensional stability and durability of concrete. This study investigated the effect of accelerated carbonation curing and further water curing on corrosion behavior, corrosion products, and pore structure of cement mortar and paste samples exposed to carbonic acid water corrosion. The results indicate the accelerated carbonation curing reduces corrosion depth and mitigates the decline in compressive strength caused by carbonic acid water corrosion. The accelerated carbonation curing can lead to the decalcification of C-S-H gel, and the formation of a large amount of CaCO3 and silica gel (SiO2·γH2O) on the surface of the C-S-H gel, which play a crucial role in the corrosion resistance of carbonic acid water. CaCO3, firstly, fills pores and optimizes the pore structure, slowing down the diffusion rate of carbonic acid water. Meanwhile, an essential "protective layer" forms on the surface due to abundant CaCO3, effectively preventing further corrosion of internal C-S-H gel, CH, C2S, and C3S. At the later age of corrosion, the carbonic acid water can lead to the decalcification shrinkage of CaCO3, and the deterioration of pore structure, which adversely affects the mechanical properties of cement-based materials.

Marine domestication of Sporosarcina pasteurii induces the precipitation of CaCO3 to solidify calcareous sand

The construction of island reef projects using natural seawater, tailored to local conditions, holds significant importance for the advancement of environmentally-friendly geotechnical engineering practices. Previous studies on the application of MICP technology in a seawater environment have been scarce. In this study, Sporosarcina pasteurii were acclimatized to a seawater environment and employed for MICP mineralization reinforcement of calcareous sand, resulting in an enhanced mineralization effect compared to previous attempts under similar conditions. Both direct domestication and gradient domestication methods proved successful in enabling Sporosarcina pasteurii to adapt effectively within a seawater environment. Following domestication, the amount of CaCO3 generated through MICP solidification increased from 2.30% to 4.47%, resulting in a corresponding increase in the Ca2+ conversion rate from 5.19% to 10.02%. Additionally, after domestication, the unconfined compressive strength (UCS) reached up to 309kPa – representing an impressive improvement of 35.53% compared to pre-domestication levels, however, it should be noted that its reinforcement effect still falls short when compared with pure water conditions. The CaCO3 minerals formed after MICP reinforcement using seawater nutrient solution in domesticated Sporosarcina pasteurii predominantly consist of needle-shaped aragonite and granular anorthite minerals, as opposed to the previously observed calcite-type CaCO3 minerals.

Assessment of the Opacity of Titanium Dioxide Free Film Coating Formulations

Titanium dioxide (TiO2) iswidely used as an excipient in pharmaceutical film coating formulations. InAugust 2022, the European commission (EC)adopted a ban on the use of TiO2 (E171) as a food additive.There is uncertainty around the implications of this decisionon pharmaceutical products, and a potential need to find suitable alternativesto TiO2. Inthis study, we evaluated the opacity of the different TF film coating systemsby assessing the ability of TF film coatings tomask coloured tablet cores at varying weight gains.HPMC-based film coatings containing CaCO3 demonstratedthe best covering potential and were positively correlated to the amount ofCaCO3 present, while PVA-based film coatings containing CaCO3showed poor coverage, even at 9% weight gain. 

Research on hydration characteristics of OSR-GGBFS-FA alkali-activated materials

Based on the characteristics of alkali-activated materials (AAMs) in energy saving and emission reduction, as well as giving full play to the complementary advantages of multi-component solid waste. In this study, a new type of AAMs was prepared from oil shale residue (OSR), ground granulated blast furnace slag (GGBFS), and fly ash (FA). Compressive and flexural strength tests, fluidity experiments, setting time, heat of hydration, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and Thermo-gravimetric analysis (DTG-TG) were used to analyse the mechanical properties, workability, mineral composition, microstructure, and hydration products of the AAMs. The results showed that the microstructure of AAMs was dense, with high early strength, good mechanical and working properties, and no tendency for retrogressive strength with an increase in the age of maintenance. Under the action of NaOH/Na2SiO3, there is a synergistic hydration of the water-hard and volcanic ash materials, and the three raw materials have synergistic hydration properties and indispensable coupling mechanisms. Meanwhile, the effect of the activator content on AAMs is bidirectional. The OSR, GGBFS, and FA in the AAMs exhibited faster hydration reactions under the action of NaOH/Na2SiO3 and abundant hydration products, which mainly included C-S-H, C-A-S-H, N-A-S-H, and small amounts of CaCO3, hydrotalcite (HT), and Ettringite (AFt). The specimens all met the requirements of the 42.5-grade composite silicate cement, and some specimens reached the strength requirements of the 62.5-grade silicate cement or above. OSR has great potential as a silicate-aluminate material, and this study provides a solid foundation for its further development and utilisation.

Calcined and Hydrated Shell Powder with Layered Porous Structures for Food Sterilization and Pesticide Residue Removal

Shell powder, a natural source product with excellent adsorption and antibacterial properties, has exhibited a broad application prospect in daily life. Herein, low-temperature calcined shell powder (LCSP) and high-temperature calcined and hydrated shell powder (HCSP) were prepared using shells as raw materials in different calcination processes. The surface structures and the chemical compositions were analyzed and the specific surface areas and pore size distributions were measured. The LCSP and HCSP reserved the unique layered porous structures of the shell. The main composition of LCSP is CaCO3, which also contains a small number of organisms. The main composition of HCSP is Ca (OH)2, which also contains CaO and a small amount of CaCO3. According to the better adsorption characteristic of the HCSP, the antibacterial activities and the removal abilities of pesticide residues of HCSP were systematically studied. The results indicated that HCSP exhibited excellent antibacterial activity (> 99.99%) and high efficiency in removing common pesticide residues (> 90%).

Study on the Antibacterial Rule in Fermented Feed with Different Amounts of CaCO3 by Quantitative Real-Time Polymerase Chain Reaction

Fermented feed is needed to maintain the vitality of probiotics and cannot be sterilized. Fermented feeds, especially those with added CaCO3, have a high risk of contamination with pathogens. Escherichia coli, Staphylococcus aureus, and Shigella flexneri are the main pathogenic bacteria threatening animal breeding. This study developed a new microbial quantitative real-time PCR analysis method to investigate the antibacterial rule in fermented feed with different amounts of CaCO3. Moreover, using the qPCR method, we found that the feed pH decreased slowly with the increase of CaCO3 addition. In the early stage of fermentation, CaCO3 addition promoted three pathogenic bacteria growth. In the middle and late fermentation, CaCO3 addition inhibited the growth of Escherichia coli and Shigella flexneri, and the greater the CaCO3 addition, the stronger the inhibitory effect. The CaCO3 addition reduced the growth inhibition of Staphylococcus aureus, and the inhibition effect was weaker with the increase of CaCO3 addition. From the inhibitory effect on intestinal pathogenic bacteria such as Escherichia coli and Shigella flexneri, the optimal addition amount of CaCO3 was 12%. At this level of addition, the number of Lactiplantibacillus plantarum subsp. plantarum, Lacticaseibacillus rhamnosus, and Bacillus subtilis were also the highest, and the content of organic acids with antibacterial effects was also the highest. The addition of CaCO3 had an inhibitory effect on the growth of pathogenic bacteria, mainly attributed to the promotion of the growth of Lactiplantibacillus plantarum subsp. plantarum and Lacticaseibacillus rhamnosus, and the organic acid of its fermentation product had an inhibitory effect on pathogenic bacteria. This study provides theoretical guidance for the antibacterial rule of high-pH fermented feed with different amounts of CaCO3.

Young’s modulus of illitic clay and CaCO3 mixtures during thermal treatment up to 1100 °C

The dynamic Young’s modulus of samples, made from a mixture of illitic clay and laboratory grade CaCO3 with 6% addition of 3% solution of polyvinyl alcohol in anorthite stoichiometry is studied. The samples with different CaCO3 contents, namely 17.6%, 21.6%, and 25.6% are made by dry pressing. The measurements of the dimensions, mass, and resonance frequency of the samples are performed for the determination of the dynamic Young’s modulus in the temperature interval from 25 °C to 1100 °C. The influence of the amount of CaCO3 on the Young’s modulus of the samples is investigated. During the firing of the studied samples, the values of Young’s modulus increase due to the liberation of physically bound water (up to 250 °C) and sintering (above 850 °C). The values of Young’s modulus after a firing reach 16.7 – 18.4 GPa, which is about 6 – 9 times higher as the values for the raw samples.

An electrokinetic-biocementation study for clay stabilisation using carbonic anhydrase-producing bacteria

This study investigates the feasibility of biocementing clay soil underneath a railway embankment of the UK rail network via carbonic anhydrase (CA) biocementation, implementing the treatments electrokinetically. Compared to previous biocementation studies using the ureolytic route, the CA pathway is attractive as CA-producing bacteria can sequester CO2 to produce biocement. Clay soil samples were treated electrokinetically using biostimulation and bioaugmentation conditions to induce biocementation. The effects of the treatment were assessed in terms of undrained shear strength using the cone penetration test, moisture content, and calcium carbonate content measurements. Scanning electron microscopy (SEM) analyses were also conducted on soil samples before and after treatment to evaluate the reaction products. The results showed that upon biostimulation, the undrained shear strength of the soil increased uniformly throughout the soil, from 17.6 kPa (in the natural untreated state) to 106.6 kPa. SEM micrographs also showed a clear change in the soil structure upon biostimulation. Unlike biostimulation, bioaugmentation did not have the same performance, although a high amount of CaCO3 precipitates was detected, and bacteria were observed to have entered the soil. The prospects are exciting, as it was shown that it is possible to achieve a considerable strength increase by the biostimulation of native bacteria capturing CO2 while improving the soil strength, thus having the potential to contribute both to the resilience of existing railway infrastructure and to climate change mitigation.

Newly deceased Caribbean reef-building corals experience rapid carbonate loss and colonization by endolithic organisms

Coral mortality triggers the loss of carbonates fixed within coral skeletons, compromising the reef matrix. Here, we estimate rates of carbonate loss in newly deceased colonies of four Caribbean reef-building corals. We use samples from living and recently deceased colonies following a stony coral tissue loss disease (SCTLD) outbreak. Optical densitometry and porosity analyses reveal a loss of up to 40% of the calcium carbonate (CaCO3) content in dead colonies. The metabolic activity of the endolithic organisms colonizing the dead skeletons is likely partially responsible for the observed dissolution. To test for the consequences of mass mortality events over larger spatial scales, we integrate our estimates of carbonate loss with field data of the composition and size structure of coral communities. The dissolution rate depends on the relative abundance of coral species and the structural properties of their skeletons, yet we estimate an average reduction of 1.33 kg CaCO3 m−2, nearly 7% of the total amount of CaCO3 sequestered in the entire system. Our findings highlight the importance of including biological and chemical processes of CaCO3 dissolution in reef carbonate budgets, particularly as the impacts of global warming, ocean acidification, and disease likely enhance dissolution processes.

Investigation of Physicochemical Properties of Qalay Abdul Ali Soil, Kabul, Afghanistan

The article presents the physicochemical properties of soil from six different areas in Qalay Abdul Ali, Kabul, Afghanistan. The authors collected dissimilar samples from six diverse areas, each with a unique profile identifier, and transported them to the research laboratory. The key objectives of this study are to recognize and profile such areas in terms of their physical and chemical characteristics and correlate them with the earlier geological periods of the Qalay Abdul Ali Region. Due to regional conflicts in the region, such quantifications are necessary as very limited data for this region existed. From the analysis, the authors assess that the soil type is gravely soil, and silt with gravels with mostly neutral pH of the soil, although, in specific regions, it was near-acidic. The amounts of CaCO3, EC (electroconductivity), and pH are dissimilar according to the locations, the values of EC, and pH within a normal range at whole locations, and the remnants of plants in various quantities. These observations recommend that the soil limitations can be used accordingly for the utilization of soil factors in the regions of the study sites and extra washbasins in the country. As the population continues to grow, such data will be critical to the future sustainability of this region.

Impact of dissolved CO2 on calcification in two large, benthic foraminiferal species.

Rising atmospheric CO2 shifts the marine inorganic carbonate system and decreases seawater pH, a process often abbreviated to 'ocean acidification'. Since acidification decreases the saturation state for crystalline calcium carbonate (e.g., calcite and aragonite), rising dissolved CO2 levels will either increase the energy demand for calcification or reduce the total amount of CaCO3 precipitated. Here we report growth of two large benthic photosymbiont-bearing foraminifera, Heterostegina depressa and Amphistegina lessonii, cultured at four different ocean acidification scenarios (400, 700, 1000 and 2200 ppm atmospheric pCO2). Using the alkalinity anomaly technique, we calculated the amount of calcium carbonate precipitated during the incubation and found that both species produced the most carbonate at intermediate CO2 levels. The chamber addition rates for each of the conditions were also determined and matched the changes in alkalinity. These results were complemented by micro-CT scanning of selected specimens to visualize the effect of CO2 on growth. The increased chamber addition rates at elevated CO2 concentrations suggest that both foraminifera species can take advantage of the increased availability of the inorganic carbon, despite a lower saturation state. This adds to the growing number of reports showing the variable response of foraminifera to elevated CO2 concentrations, which is likely a consequence of differences in calcification mechanisms.

Spatiotemporal evolution of biomineralization in heterogeneous pore structure

A fundamental understanding of the CaCO3 precipitation process in the pore network of geomaterials is important to uncover the mechanism behind the evolution of the engineering properties of geomaterials during the microbially induced carbonate precipitation (MICP) treatment. However, the details about the CaCO3 precipitation process and its interaction with the flow field at the pore scale are not well understood. In the current work, the CaCO3 precipitation process and flow field in a heterogeneous chip composed of two pore bodies, four pore throats of different sizes, and two dead-end pores are presented. The test results show that solutions can percolate through all four pore throats and diffuse into the dead-end pores at the beginning of the tests. As a result, CaCO3 can be precipitated across the chip with some difference in the number, shape, and size of crystals. Fine pore throats are more likely to be clogged, leading to solution percolating through coarse channels, thereby increasing the amount of CaCO3 in coarse channels. Precipitation in coarse channels is also ceased after a certain duration despite the continued injection of the solution. Our work provides insight into the CaCO3 precipitation process in a representative pore element, which can help to understand the mechanism behind the evolution of engineering properties and establish simulation models to predict the engineering properties of geomaterials treated by the MICP method.

The Effect of Temperature and Calcium Cloride Extract on Zinc Desorption in Changed Calcareous Soils

Zinc desorption studied for ten soils was variance in calcium carbonate, clay percent, and organic matter from Duhok province in the north of Iraq involved (Bamarny, Zawita Assih, Semeel, Kanimasi-1& 2, Khanke, Zakho, Batofa, and Faydi, locations). Soil testers after air dried up ground and filtered through a 2-mm sieve was taken to know the properties of the soils, zinc forms and desorption. Results showed the soluble, available, exchangeable and zinc total alternated among (0.29 - 0.94), (0.88 - 1.64), (1.71 - 2.05), and (12.25 - 56.15) mg.kg−1 one-to-one, Zn desorption raise with the raising of Zn added to research soils, extraction concentration CaCl2 from 0.1 to 1 molarity and temperature. Higher quantity of Zn release at 298K, was found in the soil of Kanimassi-1 (31.40 - 264.81) μg. g−1 at 0.1M, 1M CaCl2 extraction respectively, it may be owing to the high value of available phosphorus, CEC and organic matter and lower quantity of available-Zn and CaCO3. But the lowest amount observed in Faydi soil (14.10-118.69) μg. g−1. The high desorption of Zn at 321K, noted in Faydi soil between (50.50 - 421.00) μg. g−1 and low amount in Semeel soil between (26.35 - 222.10) μg.g−1 at 0.1 to 1M CaCl2 extraction respectively, designated Zn released more with increasing temperature. In general low quantity of Zn releases as of all researched soils causes to the great amount of CaCO3, quality and amount of clay minerals dominant that cause raise Zn bonding also low desorption from all studied soils. The effect of CaCl2 extraction concentration to increase Zn desorption was more than the effect of temperature in all soils.