Commercial Aluminum Sulfate Research Articles

Green industry work: production of FeCl3 from iron and steel industry waste (mill scale) and its use in wastewater treatment

Mill scale (MS) is considered to be a significant metallurgical waste, but there is no economical method yet to utilize its metal content. In this study, which covers various processes in several stages, the solution of iron in MS, which is the Iron and Steel Industry (I&SI) waste, as FeCl3 (MS-FeCl3) in the thermoreactor in the presence of HCl, was investigated. In the next step, the conditions for using this solution as a coagulant in the treatment of I&SI wastewater were investigated using the jar test. The results of the treated water sample were compared by chemical oxygen demand (COD), total suspended solids (TSS), color, and turbidity analyses using commercial aluminum sulfate (Al2(SO4)3) and FeCl3 (C-FeCl3). Additionally, heavy metal analyses were conducted, and the treatment performance of three coagulants was presented. Accordingly, while 2.0 mg/L anionic polyelectrolyte was consumed at a dosage of 4.05 mg/L Al2(SO4)3 at pH 7.0, 0.25 mg/L anionic polyelectrolyte was consumed at a dosage of 1.29 mg/L at pH 5.0 in the C-FeCl3 and MS-FeCl3 studies. Also, Fe, Cr, Mn, Ni, Zn, Cd, Hg, and Pb removal efficiencies were over 93.56% for all three coagulant usage cases. The results showed that the wastewater treatment performance of MS-FeCl3 by the recycling of MS, which is an I&SI waste, was at the same level as C-FeCl3. Thus, thanks to recycling, waste scale can be used as an alternative to commercial products for green production.Graphical abstract

Preparation of aluminium sulphate from kaolin and its performance in combination tanning

Leather making commonly use chromium salts to produce high quality products. However, the use of chromium salts is compromised by environmental safety concerns. Combination tanning using vegetable tanning coupled with aluminium sulphate can sustainably replace chrome tanning system. Adversely, the use of commercial aluminium sulphate poses economic burden that entails for cost effective sources. Abundance of kaolin on earth’s crust with scarce utilization is an opportunity towards cost effective aluminium sulphate for tanning. Therefore, in the present work aluminium sulphate was prepared from kaolin and its performance for combination tanning was studied. Diffraction and vibrational spectroscopic studies were carried out to confirm the prepared aluminium sulphate. Combination tanning was carried out with mimosa vegetable tannins. Leathers tanned with the combination of aluminium sulphate from kaolin and mimosa vegetable tannin exhibited hydrothermal stability of up to 118 °C as compared to mimosa alone that showed the average of 80 °C. Physical strength characteristics met the standard norms. Fibers separation was good as confirmed through microscopic studies. The study provides a new insight on accomplishing self-sustenance through available resources and eco-friendly manufacturing system.

Contamination Precautions for Chemicals Which May Be Used in Drinking Water Treatment

The present study aims to treat some aspects of environmental contamination under the focus of the principle of precaution, which is based on ideas and discussion about the concerns of society regarding ethics, the environment, water resources, the risk of contamination, and the uncertainties of technological applications in all areas of human knowledge. In the assessment of these scenarios it was decided to evaluate, under a critical view, the chemicals used in the treatment of drinking water, which could cause health problems, directly or indirectly, in the population. Some samples of commercial aluminium sulphate were analysed, concluding that there was a need for physical and chemical assessments to identify the origins of the raw materials used in its manufacturing process.

Enhanced performance of calcium-enriched coal ash for the removal of humic acids from aqueous solution

This study is designed to follow-up our previous work, in which we demonstrated synergistic and in-situ desulfurization effects during co-disposing shell wastes and an aqueous condensate (AQ) derived from biomass carbonization in combination with coal combustion. The potential use of Ca-enriched coal ash as a coagulant for removing humic acid (HA) from aqueous solution is explored in this study. The HA removal performance of raw and shell-added Datong (DT) coal ashes from aqueous solution is examined and compared with that of commercial aluminum sulfate (alum) and powdered activated carbons (PACs). It is found that shell-added DT ash (DTs) is markedly superior to both PACs and raw DT ash (DTr) and is even comparable to alum in terms of HA removal. The excellent HA removal performance of DTs was mainly attributable to the formation of anhydrite and lime during coal combustion. The removal efficiency of HA strongly depends on temperature, initial pH, and DTs dosage. From the results obtained in this study, it is revealed that the calcium-enriched coal ash can be used as an efficient and cost-effective coagulant to treat surface and/or waste waters that are polluted with humic substances.

MINIMIZATION OF CHEMICAL RISK BY USING RECOVERED ALUMINIUM FROM METALLURGICAL SLAG AS COAGULANT IN WASTEWATER TREATMENT

Secondary aluminium production inherently generates significant amounts of slag of variate composition and including dangerous compounds. Consequently, a care treatment of the resulted slag is imperatively necessary for preventing the environment pollution and for recovering valuable materials even if present in low amounts. The aluminium recovering procedure is based on a chemical and hydrometallurgical slag treatment, leading to the technical grade aluminium sulphate (AS), possible to be used for the chemical treatment of wastewaters, or for processing the resulted primary and secondary sludge from treatment plants. To check such a possibility, lab-scale tests have been performed by using the recovered AS from different sorts of slag coming from small or large metallurgical units of Romania. A municipal wastewater was separately treated with commercial AS and with recovered AS, the optimal dose and pH being established by mean of the standard Jar-test. The short time well mixing of wastewater allow a good dispersion of the added AS and micro-flocculation. The subsequent slow and longer mixing allows formation of large flocks easy to be separated by a gravitational method (sedimentation). The experimental results indicate no major differences in the removal efficiency of chemical oxygen demand (COD), phosphorous, and total suspended solids (TSS) between the used recovered vs. commercial AS. The recovered AS from metallurgical slag is proved as being a valuable coagulant, contributing to agglomeration of suspended solids and colloids, and to the adsorption of various dissolved chemicals or dyes from wastewaters.

Characteristics and aluminum reuse of textile sludge incineration residues after acidification

The chemical composition and aluminum speciation of sludge incineration residue (SIR) were determined. Cementation of aluminum from sulfuric acid solution using SIR was studied. The results showed that acid-soluble inorganic aluminum was the predominant component in the sludge, and the total leached aluminum increased from 62.2% to 92.9% after incineration. Sulfuric acid dosage and reaction time were found to affect aluminum recovery positively. Conversely, the increase in temperature significantly inhibited recovery reactions. The optimized leaching condition was 1.66 g sulfuric acid per gram of SIR with a reaction time of 3 hr at 20°C, resulting in the highest aluminum leaching rate of 96.7%. Compared to commercial aluminum sulfate solution coagulants, the leaching solution demonstrated higher COD Cr, turbidity and color removal efficiency for textile wastewater.

Synthesis of three commercial products from Bayer electrofilter powders

Electrofilter powders, a by-product of the Bayer process for the production of alumina from bauxite, were leached with sulphuric acid to dissolve gibbsite and transition aluminas, thus obtaining a commercial aluminium sulphate solution and a solid residue. This residue is treated again under more drastic conditions with sulphuric acidic in a furnace at a higher temperature, is then leached with water and filtered, a small amount of solid remaining (α-alumina). The liquid is a highly acidic aluminium sulphate solution which does not fulfil commercial grade specifications; the liquor is accordingly treated with potassium hydroxide or ammonium hydroxide to obtain potassium or ammonium alum. Experimental tests were conducted to investigate the synthesis of alum by crystallization. The effects on alum formation of various operating conditions, including the amount of potassium or ammonium hydroxide, temperature and seed alum dosage, were examined. The crystallization process was found to be quite effective in obtaining alum.

Recovery of coagulant from water supply plant sludge and its effect on clarification

Spent coagulant in water supply plant sludge was extracted with H2SO4 and the efficiency of the reused coagulant was studied. The optimum pH values for coagulant extraction and clarification with the reused coagulant were 3.0–4.0 and about 6, respectively. In treating raw influent obtained from a sewage treatment plant and wastewater from a coastal landfill site, the removal of chemical oxygen demand (COD), total nitrogen, and total phosphorous with the recovered coagulant was higher than that with commercial aluminum sulfate or polyaluminum chloride. In addition, the sludge settling properties, the extra sludge mass formation, the supernatant quality, and the cost of reagents were also studied. The coagulant recovered from water supply plant sludge by H2SO4 extraction could be successfully reused for the clarification of domestic and food industry wastewaters.

Results of surveys at United States pulp and paper mills for the presence of scales and precipitates containing naturally occurring radioactive material (NORM).

Field surveys were carried out at sixteen pulp and paper mills in the United States--seven kraft process, two sulfite process, and seven recycling process mills--for the presence of naturally occurring radioactive material (NORM) in precipitates and scales. NORM was detected at three of the kraft mills, one sulfite mill, and none of the recycling mills. At one of the kraft mills, the NORM was associated with a commercial aluminum sulfate ("alum") slurry used on the paper machines and in intake water treatment. The maximum activity level of this alum scale was 252,000 Bq kg(-1) (6,800 pCi g(-1)) 228Ra. At two kraft mills, NORM was associated with precipitates in the bleach plant. The measured NORM activity in samples of these scales was approximately 44,400 Bq kg(-1) (1,200 pCi g(-1)) 226Ra. Where NORM was detected at a sulfite mill, the NORM deposits were found adhering tightly to the surfaces of brownstock washers. Although samples were not removed for radionuclide analysis, survey readings at the drum surface were 26 nC kg(-1) h(-1) (100 microR h(-1)) with a scintillation counter and 2,200 cpm with a Geiger-Muller counter. At all mills, exposure rate measurements and risk assessment calculations indicated that it would be highly unlikely for any worker's annual exposure to exceed 1 mSv (100 mrem) (the Nuclear Regulatory Commission limit for untrained workers) due to exposure to these materials.

Physical and Chemical Properties of a Highly Viscous Aluminum Sulfate Melt

The physical and chemical properties of the commercial aluminum sulfate melt that do not exist in the literature were measured in this study. The aluminum content of commercial aluminum sulfate hydrate varies between 16 and 17% Al2O3. The viscosity of this product is in the range 160−260 cP, density is in the range 1.705−1.735 g/cm3, and the surface tension is predicted to be 105 dyn/cm. These properties change sharply with temperature and concentration.

4-(3,5-dichloro-2-pyridylazo)-1,3-diaminobenzene as a metallochromic indicator for the complexometric determination of Cu(II) with EDTA

In slightly acid solutions Cu(II) and 4-(3,5-dichloro-2-pyridylazo)-1,3-diaminobenzene (3,5-C12PADAB) form a red-purple complex(ϵ = 5.0 × 10 41.mole −. cm −1 at 547 nm). The complex is readily broken by EDTA, with a sharp change of colour to the yellow of the free reagent (Δλ max = 110 nm at pH 3.5). This colour contrast and the reversibility of the formation reaction, together with the solubility of the complex in water, make the pyridylazo reagent useful as a metallochromic indicator for copper titration, at pH 2.7–5.5. The Cu(II)-3,5-C12PADAB indicator system has been satisfactorily applied to the determination of sulphur in cast iron, “useful oxides” (Al 2O 3 + Fe 2O 3) in samples of commercial aluminium sulphate, and total phosphorus in a synthetic mixed fertilizer.

The use of Oxine in the analysis of commercial aluminium sulphate - a statistical approach

The analysis of commercial aluminium sulphate by precipitation of the aluminium and iron with 8-hydroxyquinoline (oxine) has been investigated. Factorial experiments were used to determine what control of experimental conditions was required for accurate results. The oxine method way compared with other methods and found to be considerably more accurate and precise, provided that correct conditions of precipitation were rigidly adhered to.

Effect of Iron on Aging of GR-S

Abstract Soluble iron decreases the resistance of the GR-S polymer to aging. The effect of iron is greater than that of copper or manganese. The aging of an aluminum sulfate—coagulated polymer can be improved by the use of low-iron aluminum sulfate instead of the commercial grade of this material. The use of commercial aluminum sulfate as a coagulant gives a polymer somewhat superior in aging to one coagulated with salt and acid. The aging of GR-S vulcanizates is accelerated slightly by polymer-soluble iron. Relatively high iron concentrations are required to produce much effect. The effect of iron on vulcanizate aging is much less than in the case of polymer aging. The presence of iron increases the rate of oxygen absorption of GR-S polymer and vulcanizates, the effect being less in the latter case. The rate of oxygen absorption of aluminum sulfate—coagulated GR-S polymer is decreased by employing low-iron aluminum sulfate instead of the commercial grade. A polymer coagulated by commercial aluminum sulfate absorbs oxygen at a slower rate than one coagulated by salt and acid.

Effect of Iron on Aging of GR-S

Abstract Soluble iron decreases the resistance of the GR-S polymer to aging. The effect of iron is greater than that of copper or manganese. The aging of an aluminum sulfate—coagulated polymer can be improved by the use of low-iron aluminum sulfate instead of the commercial grade of this material. The use of commercial aluminum sulfate as a coagulant gives a polymer somewhat superior in aging to one coagulated with salt and acid. The aging of GR-S vulcanizates is accelerated slightly by polymer-soluble iron. Relatively high iron concentrations are required to produce much effect. The effect of iron on vulcanizate aging is much less than in the case of polymer aging. The presence of iron increases the rate of oxygen absorption of GR-S polymer and vulcanizates, the effect being less in the latter case. The rate of oxygen absorption of aluminum sulfate—coagulated GR-S polymer is decreased by employing low-iron aluminum sulfate instead of the commercial grade. A polymer coagulated by commercial aluminum sulfa...