JPH04333686A - Hydroxyaluminum chloride as pitch inhibitor - Google Patents

Abstract

PURPOSE: To provide a method to treat wood pulp with aluminum hydroxide chloride so as to reduce or eliminate the pitch trouble relating to the production and treatment of pulp. CONSTITUTION: Aluminum hydroxide chloride having at least 70% basicity is added by at most 5 wt.% (to the weight of pulp after drying in an oven) to wood pulp in the system of pH about 3 to about 8 in at least one step of the treatment of pulp and/paper. By this method, paper products having excellent whiteness can be obtd. than any pulp treated with a well-known aluminum- contg. compsn.

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION Wood pulp processing and paper making techniques span a variety of principles and chemistries. One of the concerns of pulp processors is pitch control. It is now known that aluminum hydroxychloride, for example in the form of an aluminum hydroxychloride complex, can be used as an effective pitch inhibitor with relatively little reduction in the whiteness of the pulp.

[0002] Pitch has many definitions. The pitch is
It is generally considered to be a mixture of fatty acids, resin acids and unsaponifiable organic deposits of varying composition resulting from the extractable fraction in the wood. Pitch (sometimes referred to as resin or pitch resin) is the term used for an organic substance that can be extracted from wood or wood pulp by an organic solvent such as an ether. These hydrophobic extracts are normally dissolved or dispersed in the aqueous phase of the pulp slurry, but under certain processing conditions these dispersions or solutions can become unstable, resulting in pitch deposits. . However, pitch deposits may actually contain more resin than is naturally present. Pitch deposits are composed of (a) organic compounds (natural or produced by cooking processes) such as fatty acids, rosin acids and their salts, lignin and unsaponifiables; (b) insoluble inorganic salts or soaps (such as calcium carbonate,
calcium salts and fatty acids); and/or (c)
Organic and inorganic substances present in papermaking aids (e.g.
fatty acids or hydrocarbon oils found in many defoamers)
can include mixtures of.

[0003]Whether we are talking about naturally occurring pitch from virgin pulp (pitch) or pitch containing adducts from legacy processes (white pitch) that is present in recycled pulp or paper; Some people roughly divide pitch into two types, depending on how they are played. White pitch is the latex and/or
or can include organic polymers as well as organic retention materials from previous papermaking processes.

Pitch trouble pertains to both paper and pulp. Pitch trouble is particularly evident in sulfite mills and groundwood pulp (mechanical pulp) mills where the solubilizing effects of alkaline kraft processes are not present. Pitch trouble manifests itself in many ways, but the most common are dark, sticky, layered equipment deposits and sticky spheres suspended in the pulp slurry. The pitch is
(1) clumps and occludes other materials, resulting in visible "garbage" in the final paper; (2) pulp and paper processing equipment such as screens, filters, refiners, pulp washers, and paper machines; and (3) reduce the whiteness and whiteness stability of the pulp, which is a serious problem. Once pitch has adhered to mechanical parts, the only way it can be removed is by scrubbing with organic solvents or special cleaning compounds. The downtime associated with this approach reduces plant productivity.

[0005] This material fraction often undergoes many chemical reactions during pulping and bleaching, and the resin fraction is mixed with other wood components and additives during the papermaking process. Moreover, the substance fraction has complex properties and reactivity, which makes research in this field troublesome. Additionally, variations in operating variables such as temperature, electrolyte content (eg, calcium and magnesium content), or pH can cause agglomeration and precipitation of pitch deposits.

A number of approaches have been attempted, singly or in combination, to reduce the presence of pitch and/or the problems associated with processing pulp and paper containing pitch. These approaches include wood drying, wood chipping storage, kraft pulping rather than sulfite processing, adjusting the type and amount of cleaning aids and defoamers used to treat the system, and bleaching processes. and the use of pitch absorbents such as talc and clay. Still other methods that have been tried include surfactants, chelating agents, crystal modifiers (crystal modifiers), etc.
odifiers) or dispersants, addition of dispersants along with immobilizing agents and adjustment of system parameters such as equipment size.

[0007] When solving problems related to the presence of pitch in wood-based pulp during the processing of wood or paper pulp, one approach is to use alum or paper-making alum. It usually has the formula Al2(SO4)3.14H2O, but other types of alum have a different number of added water, e.g. Al2(SO4)3.18H2O.
The use of aluminum sulfate, also known as Alum can be added to the mill system many times and in many places. In papermaking equipment, alum can be added into the headbox in amounts up to 4 percent based on dry transition weight (4 percent equals 80 pounds of alum per ton of dry fiber). In a wood pulp mill, alum can be added anywhere from the pulper, refiner and/or grinder to the paper machine compounding chest. Use in pulp mills can range up to 4 percent (80 pounds per ton) in the final dry fiber.

Although it is unclear how alum actually acts to reduce pitch during pulping, it is believed that alum causes pitch to stick to the fibers of the pulp. However, there are various problems associated with the use of alum, including the fact that pitch particles stick to pulp fibers, the difficulty of handling and disposing of residual sulfate, and the slime and There is a deposition problem. Furthermore, the reduction in pulp whiteness caused by the addition of alum is a serious problem.

Several attempts have been made to replace alum. One such attempt was a cationically charged, 6.0 to 7.5 pH range devised for paper machines operating in the 6.0 to 7.5 pH range.
．． The Ge
n-Ion (registered trademark) (General Chem
ical Corporation).

None of these approaches resulted in a completely satisfactory solution to the alum substitution problem. There remains a need for a replacement for alum as a pitch suppressant, as well as products that reduce or eliminate pitch contaminants with relatively little reduction in whiteness. It also replaces known aluminum-containing materials such as alum as a pitch suppressant, and
There also still exists a need for products that can be used in H. It is therefore an object of the present invention to provide a material which can be used as a replacement for known aluminum-containing agents as pitch inhibitors during pulp processing and which provides a product with relatively little reduction in brightness. Another object of the invention is to provide a material that is effective in pitch suppression and that can be used at acidic pH.

SUMMARY OF THE INVENTION The present invention comprises a method of treating wood-based pulp with aluminum hydroxychloride to reduce or eliminate pitch problems associated with the manufacture and processing of wood-based pulp. Aluminum hydroxychloride having a basicity of at least 70 percent is added (based on the weight of oven-dried pulp) at one or more locations during pulp and/or paper processing and at a system pH within the range of about 3 to about 8. ) up to 5% by weight
is added to the wood-based pulp. Utilization of the present invention produces paper products with superior whiteness (i.e., less whiteness reversion and less whiteness loss) than pulps treated with other known aluminum-containing materials such as alum.

DETAILED DESCRIPTION OF THE INVENTION Aluminum hydroxychloride (Al2 (OH)5 Cl2) is useful when treating wood pulp and/or paper pulp to alleviate the troubles associated with the presence of pitch. It is acknowledged that there is. For the purposes of the present invention, this aluminum hydroxychloride is also referred to as aluminum hydroxychloride complex salt (AHC) (for example in its trihydrate form). The AHC used in this invention must have a basicity of at least 70 percent. Specific values for basicity are about 70 percent to about 90 percent, and more specific values are about 8.
0 percent to about 90 percent, and even more specific values are about 80 percent to about 85 percent. The percent basicity of the AHC used in this invention is the species Al (
OH) corresponds to the percentage of OH groups in 6-3.

[0013] The method of the present invention comprises within the range of about 3 to about 8;
Particularly within the range of about 4 to about 8, more particularly about 4.5
It can be used at a pH within the range of from to about 8. In contrast to other aluminum hydroxychloride materials used as pitch suppressants (e.g., Gen+Ion® materials), the present invention uses
It can be carried out at an acidic pH within the range of .

One example of AHC that is effective in the present invention is Locro
n(registered trademark) hydroxyaluminum chloride complex. Locron® AHC is an inorganic, high molecular weight compound. Locron® AHC, unlike other aluminum compounds, does not contain highly charged species (
It is thought to exist as Al13O6 (OH)24(H2O)12)+7. Locron (registered trademark)
AHC can be supplied as a solid (Locron® S, trihydrate) or liquid (Locron® L, a solution containing about 50 weight percent AHC) for ease of handling and use. . Locron
(registered trademark) L has a specific gravity of approximately 1.35 (20°C) and p
It is a colorless, transparent and odorless substance with an H value of approximately 3.6.

The invention can be used with all types of pulp. Among these pulps are 1) mechanical wood pulp, 2) pulp obtained by alkaline processes, and 3) paper pulp. Mechanical wood pulp is pulp made entirely or partially by mechanical methods and includes stone-ground wood pulp, chemical ground wood pulp, and chip mechanical pulp. Applications include newsprint, specialty papers, tissue, paper towels, paperboard and wallpaper. Mechanical wood pulp may be subdivided into three types.

a) Thermomechanical Pulp (TMP): A high yield pulp made by a thermomechanical process in which the wood particles are softened by preheating under pressure before the main refining stage. (Note: Refining steps are often performed in two or three steps.) TMP typically replaces or reduces chemical pulp components in newsprint or corrugated paper.

b) Refined groundwood pulp: Various papers having a significant portion of mechanical groundwood pulp processed in a refiner.

c) Groundwood pulp: Mechanical wood pulp made by pressing the bark-stripped material against a groundwood grindstone to reduce the wood to relatively short fibrous clumps.

Papermaking pulp is pulp used as a starting material for papermaking. Papermaking pulp can include virgin wood pulp and/or secondary materials. Secondary material is the term for fibers that have already been used in the papermaking process. The term includes paper stock utilized by recycling wet or dry waste as well as used papermaking pulp products (eg newsprint). It seems to be a common case that the paper used by recycling used paper is pulped in a separate mill as recycled papermaking pulp used as a secondary material. The waste paper was not completely dried in the paper making equipment, but it may have been out of specification, etc.
Reprocessed (or recycled from papermaking equipment)
It's paper. The waste paper can be repulped and mixed with virgin pulp and used in the headbox.

For a description of the various types of pulp and methods of their manufacture, see R.
ay A. LeaskEditMechanical
Pulping (3rd edition, 1987, Paper
Industry, Technical Assoc
ation of the Pulp an
d Paper Industry (TAPPI) and Canadian Paper and Pu
lp Association's Joint Te
xtbook Committee), Volume 2 P
ulp and Paper Manufact
Please refer to the section on ure. (See especially Chapter 7).

For the purposes of the present invention, wood-based pulp is defined to mean wood pulp (obtained by mechanical as well as alkaline methods) and paper pulp. For the examples listed herein, thermomechanical pulp made from pine wood was used.

[0022] When carrying out the process of the present invention, aluminum hydroxychloride can be added to either or both of the wood pulp and paper pulp at various stages during pulp processing. Wood pulp and paper pulp are produced and processed in a continuous manner and the AHC can be added at the beginning of the process or at one or more later stages where pitch trouble is observed. In the case of wood pulp, AHC can be added, for example, after the refining step. In the case of groundwood pulp, AHC can be added to the shower water of the grinder, for example. In the case of TMP and wood pulp processed in refiner mills, AHC can be added, for example, to the discharge side of the dormant chest. In a paper machine, for example, AHC can be added to the material in the headbox. In certain processes where pitch trouble is observed, it is preferable to add AHC. Treating the pulp in this manner means exposing the pulp to aluminum hydroxychloride in amounts sufficient to reduce or eliminate the troubles caused by the presence of pitch.

When carrying out the method of the invention, at one or more points during the pulp or paper manufacturing process described above, the aluminum hydroxychloride content in the pulp or paper, relative to the oven dry weight of the pulp or paper, is Aluminum hydroxychloride is added to the pulp in an amount such that the aluminum hydroxychloride is any amount up to 5 weight percent, more preferably any amount up to 2 weight percent. (Note that when pulp is used in papermaking, the terms pulp and paper are essentially the same.) Aluminum hydroxychloride can be added to the pulp slurry as a solid or in liquid form, such as an aqueous solution. can. Dilution of the aluminum hydroxychloride solution, eg, an aqueous solution, before addition to the wood or paper pulp is not necessary, but facilitates the use of small amounts. A specific concentration of AHC suitable for varying the concentration of AHC in the liquid and substantially reducing the degree of pitch trouble observed.
It will be understood by those skilled in the art that the amount of HC will be added. The amounts added in this invention are based on oven dry weight. Oven drying means virtually no moisture. Paper or pulp has a weight of approximately 0
．． When dried in an oven at 105 ± 3°C until it becomes constant within 1%, it is called oven drying. Oven drying seems to be a more accurate term than air drying. This is because air drying can contain as much as 10 percent moisture.

A sample calculation to determine the amount of aluminum hydroxychloride that must be added to a wood pulp slurry or paper pulp slurry to obtain the aluminum hydroxychloride content described above can be performed as follows. For an amount of 250 tons of pulp with a consistency of 4 percent, at least 0.3 tons of aluminum hydroxychloride would be added to obtain an AHC content of about 3 percent. 250 tons (4000 pounds per ton) of pulp stock with a consistency of 4 percent would represent a material containing 10 tons of solids. (Note: The term consistency is generally defined as the weight percent of air-dried or oven-dried fibrous material in a material or material suspension. Sometimes referred to as density or consistency, it is used interchangeably with weight percent. ) To obtain a 3 percent aluminum hydroxychloride additive in an oven-dried product, at least 0.3 tons (10
It would be necessary to add 0.03 tons of aluminum hydroxychloride (mixed with any required amount of water).

For the examples described herein, the wood pulp was preconditioned to simulate conditions found in a thermomechanical pulp mill. This required heating the thermomechanical pulp stock (pinewood) to about 71° C. and adding deionized water to adjust the consistency to about 3 percent. The use of this strongly basic aluminum hydroxychloride (of which Locron® is one example)
In particular, it is believed to be suitable for all pulp and paper stocks (also referred to herein as wood-based pulp), including systems that use significant proportions of recycled material or coating line waste.

Although it is not known exactly how the present invention works, strongly basic aluminum hydroxychloride, such as having a basicity of at least about 70%, can be used in combinations of resins, polymers from binders, pitch and It appears to act as a foreign material binder and sizing agent for organic and inorganic particulates such as white pitch.

It is believed that the precipitate, which has a high level of external cationic charge, neutralizes and/or restrains the anionically charged particles that adhere to the pulp so that they no longer burden the aqueous system. This precipitate has an isoelectric point of about 8. The present invention can be used in a pH range of about 3 to about 8, preferably in the range of about 4 to about 8, more preferably in the range of about 4.5 to about 8. The acidic pH range in which the present invention can be used is about 3 to 6. The pH at which the present invention is used depends on a variety of factors. For example, V-Bri
te® bleach (Hoechst Cela)
A pH in the acidic range of about 5.2 is generally preferred using bleaching agents such as those available from Nese Corporation. A neutral pH is desirable when using calcium carbonate as a filler. Cation degree
nicity) is stable and effective over a long period of time,
Therefore, it is possible to add strongly basic aluminum hydroxychloride at the very beginning of paper processing without causing a decrease in activity over time. In paper processing, highly cationic precipitates are protected from loss by cationically charged organic additives such as retention substances and are discharged, thus retaining their full effectiveness in stabilizing the system. Stabilizes cationic starch. The precipitate surrounds organic polymers such as pitch and cationizes it so that it loses its adhesive properties. Since the external charge of the precipitate is still almost the same, the particles repel each other and do not cause agglomeration.

For the practice of this invention, it is believed that the general and most convenient method of combining or mixing the AHC and pulp is to add the AHC (in dry form as an aqueous solution) to the pulp. Adding AHC and pulp to a processing vessel or system at about the same time or AHC
It is within the spirit and scope of this invention to add the wood-based pulp after the wood-based pulp is present in the container or processing system.

[0029] Also, according to the practice of the present invention, particularly acidic p
Additional benefits in the H range include reduced amounts of fine fibers (particles less than 1 mμ in size) and waste or organic additives in the aqueous system; reduced need for cationic substances; due to rapid dewatering. Improved mechanical capabilities; good retention with a high degree of filler fixation, whether originally anionically or cationically charged; up to approx. 5 (weight)
percent (approximately 10 per ton of oven-dried pulp)
reduction or elimination of pH shifts in the concentration of aluminum hydroxychloride (equivalent to 0 lbs.); avoidance of gypsum formation due to the absence of aluminum sulfate; and reduction or elimination of anomalies resulting from the formation of carbon dioxide present in other systems. It is also allowed to be included.

EXAMPLES For the examples, the pulp used was a thermomechanical pulp of South American pine wood. As mentioned above, mechanical wood pulp is any wood pulp made, in whole or in part, by mechanical methods, i.e. stone-ground wood pulp, chemical ground wood pulp, refiner mechanical pulp, thermomechanical pulp. The pulp used in this experiment was a mechanical pulp made by a thermomechanical method with high yield. The pulp was obtained from a mill and required no other processing other than adding deionized water, diluting to a 3% consistency, and heating to a typical mill temperature of about 71°C. To measure whiteness, use HunterLab D25-PC2
Brightness Meter was used.

Unless otherwise specified, chemical abbreviations and symbols have their ordinary, customary meanings, O for oxygen, H for hydrogen,
ml is milliliter, N is normal, C is degrees Celsius, 1b
indicates pounds.

Examples 1-48 The general experimental procedure used for Examples 1-48 was as follows. The 500 ml Erlenmeyer flask for each example was equipped with a stirrer and a constant temperature water bath initially set at a temperature of 71°C. Pulp samples (15 grams, dry weight of thermomechanical pine wood pulp) in each 500 ml Erlenmeyer flask.
3.25 with deionized water to facilitate mixing.
(by weight) diluted to a percent consistency. The initial pH of the pulp samples in each flask was 4.8. The pH was adjusted to approximately 5.2 using 0.1N sodium carbonate. (A pH of 5.2 was chosen as it appears to be within the optimal range for the bleaching reaction of this pulp, so that the effects of other additives on whiteness can be more easily seen.) Pulp samples were placed in a microwave oven (Whirlpool) equipped with a temperature probe.
Model MW8650XR; 1.3 cubic feet; 700 watts) was first heated to 71°C. The Erlenmeyer flask containing the pulp was then sealed with a rubber stopper and placed in a water bath to maintain a predetermined temperature before bleaching. Additives were prepared to be added to each flask. The additives had their respective solutions as follows: Locron (registered trademark) S
Hydroxy aluminum chloride complex (Hoechst
AG), and reagent grade alum (aluminum sulfate 8
Hydrate Al2 (SO4 )3.18H2 O) (Fi
Sher Certified ACS). AHC
Additives were prepared as 2 percent (w/v) solutions of their respective non-aqueous components. Alum was diluted to a specific gravity of a 2 percent solution. (The dilution was 11 ml of alum sample in 210 ml of deionized water). Next, add the indicated amounts of the additives shown in Table 1 to the specified flask while mixing, seal the flask again, and
Returned to water bath for an hour. After equilibrating for 1 hour at 71°C in a water bath, the pulp samples were alternately reduced in vacuum (to a pressure of approximately 0.9 bar) using a standard laboratory vacuum pump;
Subsequently, nitrogen was added and degassed at a pressure of approximately 1.1 bar. The degassing/nitrogen addition procedure was performed three times for each sample. The degassing/nitrogenation method appears to be necessary (at least in laboratory methods) since the oxygen present in the pulp decomposes the hydrosulfite. Bleach (V-Brite® B, Hoechst
Celanese Corp. (proprietary chemical formulation of hydrosulfite, sequestrants and stabilizers), reseal the flask and place in a water bath.
It was kept at ℃ for 1 hour. After 1 hour in the water bath, a 2.5 gram (dry weight) pulp sample was removed from each flask and
Diluted with deionized water to approximately 0.5 percent consistency. The resulting material (also referred to as furnish) was adjusted with sufficient 0.1N sulfuric acid or 0.1N sodium carbonate to give a pH of approximately 4.5±0.1 for each sample. Technical information included in this specification as reference material
Association of the Pul
p and Paper Industry (T
APPI) Jest Method T218om
- 2.5 grams and 15 cm diameter from the contents of each flask onto a Buchner funnel using the method described in 83.
I made handmade paper. Next, each handmade paper was heated to ambient temperature (approximately 2
2° C.) and 50% relative temperature for about 16 hours.

Table 1 lists the amounts of additives used in each example. Since 15 grams of oven-dried pulp was used in each example, the actual amount of additive can be calculated by multiplying the weight percent value in the table by 15 and dividing by 100. Therefore, Example 2 is 15×0.
Contains 385 ÷ 100 grams of AHC, which is AHC
Equals 0.05775 grams or approximately 0.058 grams.

[0034]

[Table 1] Example 1A-48A Examples 1A to 48A were conducted to evaluate the whiteness of the handmade paper prepared in Example 1-48. In this example, the handmade paper made in Example 1 was evaluated as Example 1A, and the same applies hereafter. Each handmade paper made in Example 1-48 was manufactured by Technic Co., Ltd., which is included herein as reference material.
al Association of the P
ulp and Paper Industry
(TAPPI), Method T452 om-
Whiteness was evaluated using the method described in 87 and the Hunter apparatus described above.

The data for these examples are shown in Table 2.

[0036]

[Table 2] na means not applicable.

This column shows data calculated by subtracting the corresponding untreated sample or blank for each experimental group from the whiteness change column. For example, Loc
Example 22 treated with ron® AHC and Example 46 treated with alum (both bleached with 1.25 percent V-Brite® bleach and the corresponding pitch of equivalent aluminum ion concentration) Locron® A
Example 22 treated with HC lost 3.1 points in brightness (10.9-7.8), whereas Example 22 treated with alum lost 5.6 points in brightness (10.9).
-5.3). In this way, Locron® AH
The samples treated with C had relatively little loss in whiteness. Note: 0.38 based on equivalent aluminum ion
The addition of 5 percent Locron® AHC is equivalent to the addition of approximately 0.5 percent alum and 0.7
The addition of 7 percent Locron® AHC is equivalent to the addition of approximately 1.0 percent alum.

EXAMPLES 49-50 COMPARATIVE EXAMPLES Examples 49-50 are white comparisons of handmade paper made using Gen+Ion® material and handmade paper made according to the present invention using aluminum hydroxychloride. This was done to compare the degree of retention. These materials were added on an equivalent aluminum ion basis.

Oven-dried unbleached pine material (210 grams) prepared according to the method of Example 1 (on a weight basis determined by drying in an oven at 105° C. until weight equilibrium was achieved) was placed in a 10 liter bucket and de-bleached. Diluted with ionized water to approximately 3% consistency. The pH of the resulting material was then adjusted to approximately 5.2 by adding a sufficient amount of dilute (0.1N) sodium carbonate. pH about 5.2
After conditioning, the sample was divided into seven equal parts, each containing approximately 30 grams of oven-dried material. Each sample weighed approximately 1000 grams. Each of the seven samples was placed in a water bath held at approximately 71° C. until the sample temperature reached equilibrium with the bath temperature (approximately 30 minutes). The additives added to the sample were diluted as follows. Additive LL consists of 20 grams of hydroxyaluminum chloride complex (Locron® S) and 5
00ml of deionized water. Additive G3 was made by mixing 20.0 grams of Gen+Ion® 9023C and 500 ml of deionized water. Additive G6 is 20.0 grams of G
Made by mixing en+Ion® 9026C and 500ml deionized water. After the samples reached equilibrium, the additives listed in Table 3 were added as indicated. It is noted that the weight percent of added Al+3 can be calculated for each sample by dividing the value listed in the last column by 20.

[0040]

[Table 3] Next, all samples were returned to a constant temperature bath (holding bath) at 71°C and kept in the bath for about 1 hour. After 1 hour in the holding bath, measure the pH of each sample and add up to 1 ml of 0.1
The pH was adjusted to about 4.5 by adding NH2SO4 or 0.1N sodium carbonate. Technical Association included herein
of the Pulp and Paper
Industry, Method T452
Two sheets of paper were made from the contents of each sample flask using the method described in OM-83. Hunter
D25-PC 2 Brightness M
Technical Association o eter, which is incorporated herein by reference.
f the Pulp and Paper
Industry, Method T452 o
The whiteness of each handmade paper was measured using the method described in M-87. Four measurements were made for each handmade paper. Table 4 shows the average value of the four values. For each sample, paper A
The average values and effect figures for Paper B (see the first sentence of Note 2 at the bottom of Table 2) are listed in Table 5. Blank value (
Note that Example 55) is 62.0. Table 5 shows that the samples treated with AHC retained their whiteness relatively well.

[0041]

[Table 4]

[Table 5]

Claims (24)

[Claims] 1. A method of treating wood-based pulp to reduce pitch-related problems, the method comprising: treating the pulp with aluminum hydroxychloride having a basicity of at least 70 percent, based on the oven dry weight of the pulp or paper. A method comprising mixing in an amount sufficient to make said pulp or said paper containing up to 5 weight percent aluminum hydroxychloride, further said method being conducted at a pH selected from the range of about 3 to about 8. 2. The method of claim 1, wherein said aluminum hydroxychloride is in the form of an aqueous solution. 3. The method of claim 1, wherein said pH is within the range of about 4 to about 8. 4. The method of claim 3, wherein said pH is within the range of about 4.5 to about 8. 5. The method of claim 1, wherein said pH is within the range of about 3 to about 6. 6. The method of claim 1, wherein the wood-based pulp is wood pulp. 7. The method of claim 6, wherein the wood pulp is a thermomechanical wood pulp. 8. The method of claim 6, wherein the wood pulp is refiner groundwood pulp. 9. The method of claim 6, wherein the wood pulp is groundwood pulp. 10. The method of claim 6, wherein said mixing occurs after said pulp refining step. 11. The method of claim 6, wherein said pH is within the range of about 3 to about 6. 12. The method of claim 1, wherein the wood-based pulp is a paper pulp. 13. The method of claim 1 or claim 12, wherein the mixing is performed in a headbox of a paper machine. 14. The method of claim 1, wherein the amount of aluminum hydroxychloride in the pulp or paper is up to 2 percent. 15. The method of claim 12, wherein said pH is within the range of about 3 to about 6. 16. A method of producing paper with reduced whiteness loss, wherein the method comprises adding aluminum hydroxychloride having a basicity of at least 70 percent to the wood pulp or papermaking grade used to make the paper. and at least one of the pulps in an amount sufficient to produce a paper containing up to 5 weight percent aluminum hydroxychloride, based on the oven dry weight of said paper, further comprising: A method carried out at a pH selected within 17. The method of claim 16, wherein the pH is within the range of about 4 to about 8. 18. The method of claim 17, wherein the pH is within the range of about 4.5 to about 8. 19. The method of claim 16, wherein the pH is within the range of about 3 to about 6. 20. Claim 16, wherein the process comprises mixing wood pulp and aluminum hydroxychloride.
the method of. 21. Claim 1, wherein the process comprises mixing paper pulp and aluminum hydroxychloride.
Method 6. 22. The method of claim 20, wherein said amount of aluminum hydroxychloride is up to 2 weight percent. 23. The method of claim 21, wherein said amount of aluminum hydroxychloride is up to 2 weight percent. [Claim 24] Claims 16, 17, 18, 19, 2
Paper made by any method according to any one of the items 0, 21, 22 or 23.