gypsum slurry leaching dosage of sodium dithionite

Notes on the Gypsum Requirement (GR) of Soil

Calcium (Ca 2+) solubilized from gypsum replaces sodium (Na +) leaving soluble sodium sulphate (Na 2 SO 4) in the water, which is then leached out Gypsum requirement (GR) is expressed as me of Ca 2+ per 100 gm soil The gypsum requirement (GR) is the calculated amount of gypsum necessary to add to reclaim the soil For calculating the dosage of gypsum needed to reclaim a particular alkali

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Sodium dithionite | Na2S2O4 PubChem

Sodium hydrosulfite is manufactured in the US by several process routes: the reaction of sodium formate (HCOONa) with caustic soda and sulfur dioxide, in an aqueous methanol solution; by reducing sodium bisulfite (NaHSO3) with electrolytically produced sodium amalgam (NaxHgx); or by reacting sulfur dioxide solution with an aqueous slurry of zinc dust and then converting the zinc salt to sodium

Leaching behaviour of impurities in waste gypsum board

Fluorides such as sodium fluoride (NaF), calcium fluoride (CaF2) and sodium hexafluorosilicate The leaching behaviour of gypsum in water was investigated 10 g of chemical gypsum samples were added to 30 cm3 of ultrapurified water and shaken for 1 hr After shaking, solid phase was separated from mixture and added to water again Figure 4 shows the microstructure of the chemical gypsum

How Much Gypsum Can You Add To Soil? Grower Today

Applying gypsum in the soil enhances the water permeation of the soil due to swelling clay and increased amounts of sodium, thus allowing water to have access and move in the soil making our crops go well This also improves the chance of the crops to survive drought as it improves the structural properties of the soil that allows the positive soilwater relations to take place Read more

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How Does Gypsum Remediate Saline And Sodic Soils?

· One of the most popular and bestknown uses of gypsum is in reclaiming saline and sodic soils and remediating irrigation waters high in sodium salts In the southwestern US (California and Arizona), Rio Grande valley and other parts of the world, soils and irrigation water can be high in salts and sodium and displacing and removing salt and sodium is a bestmanagement practice Gypsum

Effective Extraction of Cr(VI) from Hazardous Gypsum

Through controlling the phase transformation and chromium species under hydrothermal condition, the Cr(VI) was extracted fully from hazardous Cr(VI)containing gypsum sludge, with a very high efficiency of more than 995% Scanning transmission electron microscopy, Xray absorption fine structure, and density functional theory calculation results revealed that the dissolutionrecrystallization

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Orthogonal Experiments for Kaolin Bleaching by Using

Orthogonal experiments were carried out and the optimum processing conditions of the reductive bleaching were obtained as the dosage of sodium dithionite 3%, pH 2, solidtoliquid ratio 1:3 and reaction time 45min After bleaching process described above, we obtained a great improvement in the whiteness from 6993% to 8131% and a decrease of Fe2O3 content from 052% to 040% of the kaolin

Author: Jin Tang Li, Xue Zeng, Chuan Hai Gan, Shi Qiu, Rong Yi Chen, Xue Tao Luo

Process for the bleaching of pigments Kemira Chemicals Oy

First an oxidative bleaching using peracetic acid (dose 2 kg/t) and thereafter a reducing bleaching using sodium dithionite (Na 2 S 2 O 4, dose 2 kg/t) were carried out on various gypsum and kaolin grades and on one talc grade In the bleaching of talc grade 1, an ePAA solution was used, in the others, a dPAA solution was used The results of the experiments showed that a reducing further

Advanced Materials Research Vol 968 | p 3 |

The dosage of sodium dithionite, pH value, solidtoliquid ratio and reaction time were chose as factors based on monofactor experimental results Orthogonal experiments were carried out and the optimum processing conditions of the reductive bleaching were obtained as the dosage of sodium dithionite 3%, pH 2, solidtoliquid ratio 1:3 and reaction time 45min After bleaching process described

Los Angeles Regional Water Quality Control Board

Calcium Sulfate (gypsum) Sodium Dithionite • ZeroValent Iron water to create a slurry that can beapplied using a variety of techniques Minimum degradation of water quality Neither the activated carbon nor the impregnated iron has an impact on water quality such that attainment of WQOs would be affected No risk to human health as it is derived from natural virgin carbon Since

Reduction of Titanoferrous Impurities from Kaolin by

sodium dithionite bleaching, possibilities of bacterial leaching to remove high iron content present in kaolin Different strains were used to leach iron from kaolin The feed kaolin clay is highly contaminated with iron of 11% and 42% iron reduction is observed Chandrasekhar S and Ramaswamy S [3, 14] carried out detailed characterization of impurities by chemical, mineralogical and EPRS

Los Angeles Regional Water Quality Control Board

water and sodium persulfate and magnesium peroxide The chemicals will be mixed with potable water to achieve the desired slurry concentration (15%) The expected injection rate will be approximately 1 gallon per minute (gpm) During the injection, approximately 2,150 gallons of slurry

PURIFICATION OF KAOLIN BY SELECTIVE FLOCCULATION

separation, bleaching with sodium dithionite, filtering and drying In some kaolin clays from that region, titanium oxide mineral occurs in fine fraction, lower than 2 µm, and so making the industrial process more difficult The conventional method of classification and bleaching with sodium dithionite, markedly improves kaolin brightness, but has little effect on anatase removal In fact

Common whitening technology for inorganic mineral

At present, the reducing agent commonly used in the industry is sodium dithionite, commonly known as insurance powder, and its molecular formula is Na2S2O4 It is a strong reducing agent, iron oxide is soluble in acid but requires a large amount of acid, and in the presence of the insurance powder, the ferric iron in the iron oxide can be reduced to divalent iron ions

What Is Bleach and How Does It Work? ThoughtCo

· For example, sodium dithionite is a powerful reducing agent that you can use as a bleach How Bleach Chemicals Work An oxidizing bleach works by breaking the chemical bonds of a chromophore (part of a molecule that has color) This changes the molecule so that it either has no color or reflects color outside the visible spectrum A reducing bleach works by changing the double bonds

Recommended Methods of Reduction, Neutralization,

Sodium bifluoride is available in 100 Ib multiwall bags and 125, 375 and 400 Ib fiber drums The salt hydrolyzes readily, and can cause hydrofluoric acid burns to the skin Major uses of sodium bifluoride are: (1) as a laundry sour and stain remover, (2) in bleaching leather and treating hides (3) in plating tin, (4) etching and frosting

Caustic Soda Handbook Cheresources

Caustic soda (sodium hydroxide or NaOH) is most commonly manufactured by the electrolysis of a sodium chloride (NaCl) solution OxyChem manufactures caustic soda using either membrane or diaphragm electrolytic cells OxyChem does not use mercury based electrolytic cells to produce caustic soda The coproducts formed from the electrolytic production of caustic soda are chlorine and

PURIFICATION OF KAOLIN BY SELECTIVE FLOCCULATION

separation, bleaching with sodium dithionite, filtering and drying In some kaolin clays from that region, titanium oxide mineral occurs in fine fraction, lower than 2 µm, and so making the industrial process more difficult The conventional method of classification and bleaching with sodium dithionite, markedly improves kaolin brightness, but has little effect on anatase removal In fact

Enhancing Microbial Sulfate Reduction of Hydrocarbons

Concurrently, nine high pressure injections (HPIs) of gypsum slurry were conducted in other site locations (312 pounds of gypsum total) PFBs were expected to release sulfate for up to 20 years, whereas HPIs were expected to produce a shortlived plume of sulfate Concentrations of benzene and sulfate in groundwater were monitored over a 3year period in six monitoring wells In two wells near

Leaching of Valuable Elements from the Waste Chromite

Using an optimal dosage in the twostep procedure (Na2S2O4 at a dosage of 12× the stoichiometric requirement for 15 days, and then Na3PO4 in a molar ratio (ie Na3PO4: initial Cr(VI)) of 4:1 for another 15 days), the total dissolved Cr in the leachate detd via Toxicity Characteristic Leaching Procedure (TCLP Cr) testing of our samples was reduced to 38 mg/L (from an initial TCLP Cr of 112

Los Angeles Regional Water Quality Control Board

water and sodium persulfate and magnesium peroxide The chemicals will be mixed with potable water to achieve the desired slurry concentration (15%) The expected injection rate will be approximately 1 gallon per minute (gpm) During the injection, approximately 2,150 gallons of slurry

Common whitening technology for inorganic mineral

At present, the reducing agent commonly used in the industry is sodium dithionite, commonly known as insurance powder, and its molecular formula is Na2S2O4 It is a strong reducing agent, iron oxide is soluble in acid but requires a large amount of acid, and in the presence of the insurance powder, the ferric iron in the iron oxide can be reduced to divalent iron ions

Sulfating Patents and Patent Applications (Class 423/199

Abstract: In the production of anhydrous sodium dithionite by reacting sodium formate, an alkaline sodium compound and sulfurous acid anhydride in hydrous methanol, a process for treating the mother liquor, which comprises adding an alkali to the mother liquor left after the separation of the resulting anhydrous sodium dithionite to adjust its pH to at least 8, separating the solids

Final Summary Report of Mineral Industry Processing

The only area of potential generation of a vaste of concern is the leaching (brightening, whitening) step which uses acids, ozone or strong reducing agents (hydrosulfite) to remove the ironcompounds that color the clay If the liquid from this step is discharged it could present a potentially hazardous waste Ball and refractory clays are not normally processed to this extent The final

Recommended Methods of Reduction, Neutralization,

Sodium bifluoride is available in 100 Ib multiwall bags and 125, 375 and 400 Ib fiber drums The salt hydrolyzes readily, and can cause hydrofluoric acid burns to the skin Major uses of sodium bifluoride are: (1) as a laundry sour and stain remover, (2) in bleaching leather and treating hides (3) in plating tin, (4) etching and frosting

Caustic Soda Handbook Cheresources

Caustic soda (sodium hydroxide or NaOH) is most commonly manufactured by the electrolysis of a sodium chloride (NaCl) solution OxyChem manufactures caustic soda using either membrane or diaphragm electrolytic cells OxyChem does not use mercury based electrolytic cells to produce caustic soda The coproducts formed from the electrolytic production of caustic soda are chlorine and

Water Technology Articles – Page 2 – Water Technology

· Na 2 S 2 O 4 sodium hydrosulfite Each cleaning procedure is unique depending on the nature of the foulant and the system operation In general, it is best to remove organic foulants first with an alkalinity cleaning (high pH) followed by an acid cleaning (low pH) for inorganic scale and metals removal Begin the alkaline cleaning by filling the CIP (clean in place) tank with permeate