Study on Preparation of Titanium Dioxide from Low Iron and Rich Titanium Slag with Acid Hydrolysis Technical

2012 ◽  
Vol 554-556 ◽  
pp. 682-686
Author(s):  
Zhi Yong Hu
Keyword(s):  
Titanium Dioxide ◽  
Sulfuric Acid ◽  
Acid Hydrolysis ◽  
Process Parameters ◽  
Sulfuric Acid Concentration ◽  
Curing Temperature ◽  
Hydrolysis Rate ◽  
Optimum Process ◽  
Curing Time ◽  
Titanium Slag

Titanium dioxide is an important inorganic chemical product, and low iron and rich titanium slag can be made into titanium dioxide. In this paper, process parameters for preparing titanium dioxide were investigated. The results show that with the increase of sulfuric acid concentration, curing time and curing temperature, the rate of sulfuric acid hydrolysis rate will be improved, as well as charging temperature. According to the orthogonal test, the optimum process parameters condition of sulfuric acid is 95% sulfuric acid, 180°C reaction temperature, and 120min curing time.

Study on the Durability of Fluorinated Water and Oil Repellent Finishing by Contact Angle Method

2012 ◽  
Vol 482-484 ◽  
pp. 1294-1297
Author(s):  
Dian Wei Zhang ◽  
Yong Zhu Cui ◽  
Yan Ling Sui
Keyword(s):  
Contact Angle ◽  
Curing Temperature ◽  
Cross Linking ◽  
Optimum Process ◽  
Curing Time ◽  
Repellent Property ◽  
Finishing Agent ◽  
Oil Repellent ◽  
Angle Method

In this paper, fluorinated water and oil repellent finishing agent was mixed with auxiliary agents and the durability of fabrics treated with the finishing agent was investigated. The water and oil repellent property was discussed and evaluated by contact angle method. The results showed that under the same conditions, adding 0.4% cross-linking agent could make the contact angle of the treated fabric higher than untreated, and the durable-washing property of the fabric was excellent and the durability of fluorinated water and oil repellent finishing agent got improved greatly. The optimum process was that the dosage of water and oil repellent finishing agent was 50g/L, the dosage of cross-linking agent was 4g/L, curing temperature was 160 °C and curing time was 90s.

Moisture Absorption Finishing of Polyester Fabric

2013 ◽  
Vol 275-277 ◽  
pp. 2182-2185
Author(s):  
Jun Zhang
Keyword(s):  
Moisture Absorption ◽  
Process Condition ◽  
Polyester Fabric ◽  
Curing Temperature ◽  
Optimum Process ◽  
Curing Time ◽  
Drying Time ◽  
Moisture Management ◽  
Finishing Agent

Polyester fabric was finished by water-absorbent and quick-dry agent Casofter-252 and moisture management agent Hipom-790 for improving its moisture management property. The quality of moisture absorption finishing of the polyester fabric was detected in terms of wicking height and fast drying time. And the influence of agent concentration, pH, and curing temperature and time on moisture management property was studied in order to obtain the optimum process condition. The best choice for Casofter-252 was agent concentration 20g/L, pH 3, curing temperature 135 oC, curing time 120s, and the optimum finishing condition for Hipom-790 was as follows: agent concentration 30g/L, pH 5, curing at 115 oC for 140 s. The finished polyester fabric under the optimum condition showed much better air permeability. The tensile strength of the fabric increased after moisture finishing with Hipom-790 while it decreased for Casofter-252 used as a finishing agent.

scholarly journals Cleaner Production of Chromium Oxide from Low Fe(II)-Chromite

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 460 ◽  
Author(s):  
Qing Zhao ◽  
Chengjun Liu ◽  
Peiyang Shi ◽  
Lifeng Sun ◽  
Maofa Jiang ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Processing Parameters ◽  
Dissolution Behavior ◽  
Optimum Process ◽  
Process Conditions ◽  
Box Behnken Design ◽  
Functional Relationships ◽  
Leaching Process

Sulfuric acid-based leaching is a promising cleaner method to produce chromium salts, but its feasibility for treating low Fe(II)-chromite still remains to be proven. A Box–Behnken design (BBD)-based set of experiments for sulfuric acid leaching of low Fe(II)-chromite was utilized in this work for generating an experimental dataset for revealing the functional relationships between the processing parameters and the extraction yields of Cr and Fe. The dependent variables were found to exhibit strong intercorrelations and the models developed on the basis of statistical criteria showed excellent prediction accuracy. The optimum process conditions of leaching treatment were found to be a temperature of 176 °C, a dichromic acid/chromite mass ratio of 0.12, and a sulfuric acid concentration of 81%. Furthermore, the dissolution behavior of chromite in the leaching process and the effect of dichromic acid were experimentally investigated. It was found that the decomposition efficiency was highly dependent on the Fe(II) content of chromite, and that the dichromic acid acted both as an oxidant and a catalyst in the leaching process. On the basis of the results of this study, a novel process for treating low-Fe(II) chromite was proposed.

The hydrolyses of some sterically crowded benzoate esters in sulfuric acid. The excess acidity method at different temperatures

1979 ◽  
Vol 57 (22) ◽  
pp. 2960-2966 ◽  
Author(s):  
Robin A. Cox ◽  
Malcolm F. Goldman ◽  
Keith Yates
Keyword(s):  
Sulfuric Acid ◽  
Activation Enthalpy ◽  
Sulfuric Acid Concentration ◽  
Hydrolysis Rate ◽  
Water Molecules ◽  
Steric Strain ◽  
Methyl Substitution ◽  
Different Temperatures ◽  
Acid Catalyzed ◽  
Aqueous Standard

The excess acidity method has been used to analyze the observed acid-catalyzed hydrolysis rate constants for methyl benzoate, methyl para-toluate, methyl ortho-toluate, and methyl 2,6-dimethylbenzoate, over a wide sulfuric acid concentration range, at several different temperatures. Enthalpies and entropies of activation in the aqueous standard state are reported, with slope parameters m≠ also given are the [Formula: see text] and m* values found for the protonation of these compounds. The mechanistic changeover from AAc-2 to AAc-1 hydrolysis occurs at lower acidity with increasing methyl substitution, mainly due to the decrease in activation enthalpy in the transition state for the AAc-1 process, caused by release of steric strain and increased mesomeric interaction. The AAc-2 hydrolysis involves two water molecules, and is energetically favourable and entropically unfavourable. The AAc-1 reaction is difficult energetically, but this is offset by the large positive activation entropies found.

Bitumen Modification

2014 ◽  
Vol 880 ◽  
pp. 3-6 ◽  
Author(s):  
Olga I. Slavgorodskaya ◽  
Vladimir G. Bondaletov ◽  
Yulia P. Ustimenko
Keyword(s):  
Process Parameters ◽  
Curing Temperature ◽  
Optimum Process ◽  
Properties Of Coatings ◽  
Bitumen Modification

The possibility of using epoxidized petroleum resins for modification of bitumen was shown. The dependence of the properties of coatings based on polymeric-bitumen compositions of the number of modifiers, hardening agent and the curing temperature was investigated. The optimum process parameters for polymeric-bitumen compositions were identified. The resistance of the coatings to different environments was investigated.

scholarly journals Conversion of hemicellulose from kenaf core fiber to xylose through dilute sulfuric acid hydrolysis

2019 ◽  
Vol 21 (1) ◽  
pp. 14-22 ◽  
Author(s):  
William Judiawan ◽  
Yanni Sudiyani ◽  
Elda Nurnasari
Keyword(s):  
Sulfuric Acid ◽  
Acid Hydrolysis ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Heating Time ◽  
Hibiscus Cannabinus ◽  
Kenaf Core ◽  
Dilute Sulfuric Acid ◽  
Acid Ratio ◽  
Xylose Concentration

Kenaf (Hibiscus cannabinus) is a lignocellulosic plant that is usually utilized as a fiber source for sack production. The core from kenaf fiber has not been utilized yet in Indonesia, therefore it is still considered as a waste. Hemicellulose from kenaf core can be hydrolyzed to xylose through dilute sulfuric acid hydrolysis in high temperature. Hydrolysis in this study was done by using autoclave at 121℃ and 10% (m/v) biomass: acid ratio for 15 and 45 minutes with a variation on acid concentration (2%, 4%, and 6% v/v). Xylose concentration in the hydrolyzate tends to increase with higher acid concentration and longer heating time. 6% (v/v) sulfuric acid concentration and 45 minutes of heating time produce the highest xylose concentration (20.53 gr/L) and yield (86.50%)

The hydrolyses of benzamides, methylbenzimidatium ions, and lactams in aqueous sulfuric acid. The excess acidity method in the determination of reaction mechanisms

1981 ◽  
Vol 59 (19) ◽  
pp. 2853-2863 ◽  
Author(s):  
Robin A. Cox ◽  
Keith Yates
Keyword(s):  
Sulfuric Acid ◽  
Water Molecule ◽  
Reaction Pathway ◽  
Sulfuric Acid Concentration ◽  
Strong Acid ◽  
Hydrolysis Rate ◽  
Reaction Conditions ◽  
Acid Media ◽  
Hydrolysis Of

The excess acidity method has been applied to hydrolysis rate data for a number of benzamides, methylbenzimidatium ions, and lactams, obtained as a function of sulfuric acid concentration and temperature. All of the substrates studied except β-propiolactam (8) and methyl-2,6-dimethylbenzimidatium ion (7) were found to follow the AOT2 mechanism at all acidities. The excess acidity method provided considerable mechanistic detail; in dilute acid the transition state contains O-protonated (or methylated) substrate and three water molecules (large negative ΔS≠), but in more concentrated solutions a one-water-molecule mechanism takes over (smaller negative ΔS≠). In strong acid bisulfate ion acts as the nucleophile (positive ΔS≠). N-protonated intermediates are not involved for "normal" substrates, being observed in this work only for 8, which follows the AND1 pathway. Observed differences between benzamide and methylbenzimidatium ion (4) hydrolyses are due to their differing activity coefficient behaviour, the mechanism being the same for both. The hydrolysis of 7 involves a one-water-molecule SN2 displacement at the O-methyl group. Comparison with 7 shows that this displacement is not likely to occur under the reaction conditions for 4; however, for the N-methyl and N,N-dimethyl derivatives studied it is probably an important reaction pathway. A comprehensive mechanistic framework for amide hydrolyses in strong acid media is given.

Study on Sugar Production Conditions of Dilute Sulfuric Acid Hydrolysis of Corn Straw

2014 ◽  
Vol 1008-1009 ◽  
pp. 97-100
Author(s):  
Qing Sun ◽  
Shu He Huang ◽  
Bo Wang ◽  
Xiao Run Deng ◽  
Jia Sheng Yi ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Reaction Time ◽  
Acid Hydrolysis ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Sugar Yield ◽  
Corn Straw ◽  
Experimental Conditions ◽  
Dilute Sulfuric Acid ◽  
Hydrolysis Of

In this paper, through the study of reducing sugar conditions of corn straw hydrolysis under acidic condition, looking for the production of experimental conditions relatively reasonable. Mainly by dilute sulfuric acid hydrolysis of corn straw by single factor test, effects of sulfuric acid concentration, temperature, reaction time, particle size, ratio of solid to liquid five factors, effects on sugar yield of corn straw. The dilute sulfuric acid concentration 5%, ratio of solid to liquid was 1:14, when the reaction time is 140 min, particle fineness of 120 mesh, the reaction temperature is 100 °C, corn stalk sugar yield reached a maximum 20.11%.

Study on the Hydrolysis of Corn Stalk and Photosynthetic Bacteria Group Fermentation Hydrogen Production

2011 ◽  
Vol 194-196 ◽  
pp. 2187-2190
Author(s):  
Bao Chen Cui ◽  
Guo Xin Zhang ◽  
Bo Hou ◽  
Jing Yan Zhao ◽  
Rui Li
Keyword(s):  
Sulfuric Acid ◽  
Hydrogen Production ◽  
Acid Concentration ◽  
Photosynthetic Bacteria ◽  
Sulfuric Acid Concentration ◽  
Optimum Process ◽  
Process Conditions ◽  
Hydrogen Yield ◽  
Corn Stalk ◽  
Hydrolysis Temperature

Hydrogen production of photosynthetic bacteria group (PSBG) was studied using corn stalk hydrolyzate as hydrogen production substrate. The effects of sulfuric acid concentration, hydrolysis pH values and hydrolysis temperature on hydrogen production were investigated. The optimum process conditions were as follows: the sulfuric acid concentration was 1%, hydrolysis pH value was 6.0 and the hydrolysis temperature was 110°C , respectively. Three hydrolyzate detoxification methods were compared. The method of calcium hydroxide obtained the optimal detoxification effect and the maximum hydrogen yield was 472 mL H2/ (L-medium).

Kinetic Study on Sulfuric Acid Dissolution of NaxH2-xTiO3 from Sodium Hydroxide Molten Method

2014 ◽  
Vol 881-883 ◽  
pp. 1545-1548 ◽  
Author(s):  
Wei Jing Wang ◽  
Tian Yan Xue ◽  
Dong Wang ◽  
Tao Qi
Keyword(s):  
Experimental Data ◽  
Sulfuric Acid ◽  
Sulfuric Acid Concentration ◽  
Product Layer ◽  
Dissolution Kinetic ◽  
Shrinking Core Model ◽  
Acid Dissolution ◽  
Titanium Slag ◽  
Slag Treatment ◽  
Shrinking Core

The dissolution kinetic of NaxH2-xTiO3(resulting from high titanium slag treatment by NaOH) by diluted sulfuric acid (38~51 wt. %) was carried out in temperature range of 10 to 50°C with an initial acid/NaxH2-xTiO3(wt.) ratio of 1:1. The effects of the sulfuric acid concentration and temperature on titanium dissolution percent were reported, and both of them significantly affected the dissolution rate. The experimental data indicate that the shrinking core model controlled by diffusion in product layer is most applicable for the titanium dissolution process, and the apparent activation energy has been estimated to be 28.69 kJ/mol.

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